Dissertations / Theses: 'Plants Requirements'

1

Naku, Mandilakhe. "Functional role of ammonium and nitrate in regulating transpiration for mass-flow acquisition of nutrients in Phaseolus vulgaris L." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2679.

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Thesis (MTech (Horticulture))--Cape Peninsula University of Technology, 2017
Transpiration serves in leaf cooling, maintaining turgor pressure, promoting xylem transport of nutrient solutes from roots to shoots and delivering mobile soil nutrients to root surfaces. Soil availability of nitrogen can modulate transpiration rates, consequently powering nutrient delivery to the root surfaces (‗mass-flow'). Although such knowledge on N-regulation of transpiration is available, it remains unknown, however, whether it is NO3- or NH4+ that regulates transpiration. Given that both nitrogen forms co-occur in soils, it is not known how they interact at varying ratios in modulating stomatal behaviour. To test the functional role of NO3- and NH4+ in regulating water fluxes for mass-flow nutrient acquisition, P. vulgaris L. plants were grown with NO3- or NH4+ placed at one of four distances behind a nylon mesh, which prevented direct root access to nitrogen, whilst control plants intercepted the nitrogen source (Chapter 3). Day- and night-time stomatal conductance and transpiration, measured using Infra-Red Gas Analyser (IRGA) declined in NO3- fed plants with the increased distance behind a nylon mesh, with maximum water fluxes at the closest distance (ca. 0 mm), demonstrating a regulatory role of NO3- on stomata closure. An opposite trend was displayed by NH4+ -fed plants, which indicated the incapacity of NH4+ to down-regulate water fluxes and ammoniacal syndrome at high concentrations. To test how different [NO3-] and [NH4+] regulate day- and night-time stomatal conductance and transpiration (Chapter 4), P. vulgaris was fed with six concentrations (0, 0.25, 0.5, 1, 2, 4 and 8 mM) of each nitrogen form. A biphasic trend emerged, as postulated in previous studies (Wilkinson et al., 2007; Matimati et al., 2013), characterized by an increase in stomatal conductance and transpiration as [NO3-] increased, attaining a maximum before declining with higher [NO3-]. Plants displayed 2-fold higher photosynthetic rates, 2.2-fold higher stomatal conductance and 2.3-fold higher transpiration rates at 4 mM than at 0.25 mM of [NO3-]. The lowest [NO3-] up-regulated night-time stomatal conductance and transpiration, indicating that NO3- -fed plants opened their stomata at night-time, but reduced night-time water loss at higher [NO3-]. NH4+-fed plants had the incapacity to regulate day- and night-time water fluxes, but rather displayed wilting and stress known as ‗ammoniacal syndrome'. Thus, under NO3- deprived soil conditions P. vulgaris may be opportunistic in their water uptake, transpiring more when water is available in order to draw nutrients through ‗mass-flow'. This thesis explored and confirmed the functional role of NO3- in regulating day- and night-time water fluxes as a mechanism for increasing ‗mass-flow' acquisition of N and possibly other nutrients, signalling a down-regulation of day-time and night-time water fluxes when [NO3-] is replete (Chapter 3 & 4). Where both NO3- and NH4+ are present in soils, it is the [NO3-] and not [NH4+] that regulated stomatal conductance and transpiration. Since organic nitrogen forms such as amino acids also occur in soils, there is a need for further work on their role in stomatal behaviour. Using amino acids laced with 15N isotopes as a nitrogen source can allow their acquisition and role on stomatal behaviour to be discovered. Current trends in research are focussed around developing real-time in-situ sensing of soil nitrogen status to promote enhanced nitrogen and water use efficiency in agricultural systems. This thesis provides the vital literature on stomatal regulation by [NO3-].

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2

Cosby, Dana. "Core Communication Skills Requirements Manufacturing Plants in Kentucky." TopSCHOLAR®, 1994. http://digitalcommons.wku.edu/theses/938.

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The purpose of this reseach project is to answer the question "What are the core communication skills needed for pre-hire training programs in Kentucky." To answer the question the researcher first examined the literature relative to the existing labor pool and then conducted a focus group with unemployed persons. The next phase of the research involved extensive field work, job analysis, and content analysis to determine what core communication skills were common in various Kentucky manufacturing companies. The researcher found strong evidence to establish a core set of competencies that pre-hire programs should address in developing the skills of unemployed persons. Additionally, the study includes a sample curriculum for pre-hire training programs.

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3

Mulyati. "Zinc requirements of transplanted oilseed rape." Thesis, Mulyati, (2004) Zinc requirements of transplanted oilseed rape. PhD thesis, Murdoch University, 2004. https://researchrepository.murdoch.edu.au/id/eprint/213/.

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Transplanting is a common practice for many horticultural crops and some field crops. Recently, transplanted oilseed rape (Brassica napus L.) crops have been reported to be sensitive to zinc (Zn) deficiency. However, Zn nutrition in transplanted field crops has not been investigated in detail. The objectives of this present research were to investigate whether transplanting increases external Zn requirements of transplanted oilseed rape, and the mechanisms of root function, growth and Zn uptake after transplanting including rhizosphere modification capacity by plant roots. The second objective was to examine the relative effects of root pruning and transplanting on Zn responses of oilseed rape, and the third objective was to determine external and internal Zn requirements of transplanted oilseed rape for diagnosing and predicting Zn deficiency. An experiment on a low Zn sand (DTPA extractable Zn 0.14 mg kg-1) was set up to determine whether transplanted oilseed rape had a higher Zn requirement than that of direct-sown plants. Low Zn supply depressed shoot dry weight, however, root growth was relatively more strongly suppressed than shoots. Maximum root dry weight required much higher external Zn for transplanted plants compared to direct-sown plants, whilst shoot dry weight required a similarly low external Zn supply. In addition, transplanted plants were sensitive to zinc deficiency during the early post-transplanting growth, and the response weakened as the plants recovered from root injury or transplanting stress. However, the transplanted plants also experienced root pruning before transplanting and so in this experiment the higher Zn requirement could have been due to root pruning or transplanting or both. A further experiment was undertaken to determine the comparative external Zn requirements of direct-sown and transplanted plants in well-stirred chelate-buffered solution culture where a rhizosphere effect on plant availability of Zn forms is absent and the effects of poor root-soil contact on post-transplanting growth are minimized. In solution culture at the same level of Zn supplied, direct- sown plants produced higher shoot and root dry matter and greater root length than those of transplanted plants. However, since a higher external Zn requirement was found for transplanted plants in buffered solution culture than for direct- sown plants, it was concluded that the higher Zn requirement was not related to decreased rhizosphere modification, to greater demand for Zn or to poor root-solution contact, but rather to the time required for transplanted plants to recover from transplanting and root injury. The recovery of root function in solution culture was more rapid than that in soil culture and expressed as a higher Zn requirement for shoot as well as root growth. It suggested that the delay in root recovery in soil culture was due to slower absorption of Zn from the soil after transplanting than was the case in solution culture. Chelate-buffered nutrient solution culture and harvesting plants successively at 5 day intervals until 25 days after transplanting was used to examine the mechanisms of the recovery of root growth and function. In this experiment, the external Zn requirement of transplanted plants was investigated with unpruned or pruned root systems. Plants with unpruned root system and sufficient Zn supply exhibited faster recovery from transplanting than those with pruned root system plants. The results suggest that root pruning impaired Zn uptake by plant roots and slowed down the root and shoot growth after transplanting. Increased solution Zn partly alleviated the effects of root pruning and presumably this is a major reason why transplanted oilseed rape had a high external Zn requirement. However, root pruning also appeared to impair water uptake, and may have suppressed shoot growth through sequestering carbon for new root growth and through decreased phytohormone production by roots. Since rapid root recovery of transplanted plants is essential for successful of growth in the field, Zn application to the nursery bed was explored as a starter fertilizer to stimulate root growth after transplanting. The objective of this experiment was to determine whether increasing the seedbed Zn would stimulate new root growth of transplanted oilseed rape, and therefore would alleviate the need for increased external Zn for post-transplanting growth. Results showed that adequate Zn concentration in the seedbed promoted the post-transplanting growth by stimulating the new root growth especially increased root length, and also hastened the recovery of root systems. However, high Zn concentration at transplanting still had a more dominant effect in stimulating the new root growth of oilseed rape after transplanting. The final experiment was set up using rhizobags with three rates of Zn supply and unpruned or pruned root systems. The purpose of this study was to investigate the chemical change in the rhizosphere and non-rhizosphere or bulk soil and its relationship to the recovery of root function after transplanting, and also to identify and quantify the organic acids in soil extracts of direct-sown and transplanted plants. The rhizosphere soil pH was lower than that of non-rhizosphere soil, and the decrease of soil pH was suggested as the mechanism of the increase of Zn availability and mobility in the rhizosphere soil. Direct-sown plants were more efficient in utilizing Zn than those of transplanted plants especially compared to those of plants with pruned root system. Zinc deficient plants excreted higher concentration of organic acids particularly citric acid, suggesting this was a mechanism of Zn mobilization and Zn uptake by roots of oilseed rape. The main implications of the present study for the management of Zn nutrition of transplanted crops were: the need to increase the Zn application to crops in the nursery and at transplanting compared to direct-sown plants; the possibility that external requirements of other nutrients will be greater in transplanted crops also requires further consideration; and in cropping systems where transplanting is practised, greater attention should be given to the avoidance of root damage during the transplanting.

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4

Mulyati. "Zinc requirements of transplanted oilseed rape." Murdoch University, 2004. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20060109.135933.

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Transplanting is a common practice for many horticultural crops and some field crops. Recently, transplanted oilseed rape (Brassica napus L.) crops have been reported to be sensitive to zinc (Zn) deficiency. However, Zn nutrition in transplanted field crops has not been investigated in detail. The objectives of this present research were to investigate whether transplanting increases external Zn requirements of transplanted oilseed rape, and the mechanisms of root function, growth and Zn uptake after transplanting including rhizosphere modification capacity by plant roots. The second objective was to examine the relative effects of root pruning and transplanting on Zn responses of oilseed rape, and the third objective was to determine external and internal Zn requirements of transplanted oilseed rape for diagnosing and predicting Zn deficiency. An experiment on a low Zn sand (DTPA extractable Zn 0.14 mg kg-1) was set up to determine whether transplanted oilseed rape had a higher Zn requirement than that of direct-sown plants. Low Zn supply depressed shoot dry weight, however, root growth was relatively more strongly suppressed than shoots. Maximum root dry weight required much higher external Zn for transplanted plants compared to direct-sown plants, whilst shoot dry weight required a similarly low external Zn supply. In addition, transplanted plants were sensitive to zinc deficiency during the early post-transplanting growth, and the response weakened as the plants recovered from root injury or transplanting stress. However, the transplanted plants also experienced root pruning before transplanting and so in this experiment the higher Zn requirement could have been due to root pruning or transplanting or both. A further experiment was undertaken to determine the comparative external Zn requirements of direct-sown and transplanted plants in well-stirred chelate-buffered solution culture where a rhizosphere effect on plant availability of Zn forms is absent and the effects of poor root-soil contact on post-transplanting growth are minimized. In solution culture at the same level of Zn supplied, direct- sown plants produced higher shoot and root dry matter and greater root length than those of transplanted plants. However, since a higher external Zn requirement was found for transplanted plants in buffered solution culture than for direct- sown plants, it was concluded that the higher Zn requirement was not related to decreased rhizosphere modification, to greater demand for Zn or to poor root-solution contact, but rather to the time required for transplanted plants to recover from transplanting and root injury. The recovery of root function in solution culture was more rapid than that in soil culture and expressed as a higher Zn requirement for shoot as well as root growth. It suggested that the delay in root recovery in soil culture was due to slower absorption of Zn from the soil after transplanting than was the case in solution culture. Chelate-buffered nutrient solution culture and harvesting plants successively at 5 day intervals until 25 days after transplanting was used to examine the mechanisms of the recovery of root growth and function. In this experiment, the external Zn requirement of transplanted plants was investigated with unpruned or pruned root systems. Plants with unpruned root system and sufficient Zn supply exhibited faster recovery from transplanting than those with pruned root system plants. The results suggest that root pruning impaired Zn uptake by plant roots and slowed down the root and shoot growth after transplanting. Increased solution Zn partly alleviated the effects of root pruning and presumably this is a major reason why transplanted oilseed rape had a high external Zn requirement. However, root pruning also appeared to impair water uptake, and may have suppressed shoot growth through sequestering carbon for new root growth and through decreased phytohormone production by roots. Since rapid root recovery of transplanted plants is essential for successful of growth in the field, Zn application to the nursery bed was explored as a starter fertilizer to stimulate root growth after transplanting. The objective of this experiment was to determine whether increasing the seedbed Zn would stimulate new root growth of transplanted oilseed rape, and therefore would alleviate the need for increased external Zn for post-transplanting growth. Results showed that adequate Zn concentration in the seedbed promoted the post-transplanting growth by stimulating the new root growth especially increased root length, and also hastened the recovery of root systems. However, high Zn concentration at transplanting still had a more dominant effect in stimulating the new root growth of oilseed rape after transplanting. The final experiment was set up using rhizobags with three rates of Zn supply and unpruned or pruned root systems. The purpose of this study was to investigate the chemical change in the rhizosphere and non-rhizosphere or bulk soil and its relationship to the recovery of root function after transplanting, and also to identify and quantify the organic acids in soil extracts of direct-sown and transplanted plants. The rhizosphere soil pH was lower than that of non-rhizosphere soil, and the decrease of soil pH was suggested as the mechanism of the increase of Zn availability and mobility in the rhizosphere soil. Direct-sown plants were more efficient in utilizing Zn than those of transplanted plants especially compared to those of plants with pruned root system. Zinc deficient plants excreted higher concentration of organic acids particularly citric acid, suggesting this was a mechanism of Zn mobilization and Zn uptake by roots of oilseed rape. The main implications of the present study for the management of Zn nutrition of transplanted crops were: the need to increase the Zn application to crops in the nursery and at transplanting compared to direct-sown plants; the possibility that external requirements of other nutrients will be greater in transplanted crops also requires further consideration; and in cropping systems where transplanting is practised, greater attention should be given to the avoidance of root damage during the transplanting.

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5

Peter, Craig Ingram. "Water requirements and distribution of Ammophila arenaria and Scaevola plumieri on South African coastal dunes." Thesis, Rhodes University, 2000. http://eprints.ru.ac.za/38/.

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6

Defiani, Made Ria. "Zinc requirements of rice at elevated CO2 /." [Richmond, N.S.W.] : Centre for Horticulture and Plant Sciences, University of Western Sydney, Hawkesbury, 1999. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030519.171711/index.html.

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7

Leda, Carol E. "Iron and manganese requirements of containerized plants growing in pine bark." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/91043.

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Three species of woody plants, Ilex crenata 'Helleri', Juniperus chinensis procumbens 'Nana', and Ligustrum lucidum, were grown in one-liter containers filled with pine bark to determine Fe and Mn requirements with regard to rate and ratio. FeEDTA and MnEDTA were applied at either a 2:1 or 1:2 ratio of Fe:Mn at 5 concentrations each, 3 times per week with each irrigation. Medium solutions were collected every 21 days on one species and analyzed for Fe and Mn levels. Dry weight and tissue Fe and Mn levels were determined for all three species. Neither rate nor ratio of applied Fe and Mn had an effect on shoot dry weights. Control treatments, in general, had the lowest medium solution and tissue levels of Fe and Mn, however, there was no difference in dry weights between control and treatment plants. These results suggest that pine bark supplies adequate levels of Fe and Mn for growth under the conditions of this study. In a second study, three sources of Fe and Mn were applied to Tagetes erecta 'Inca' growing in 500 cc plastic pots containing sieved pine bark at 3 lime rates: 0, 3, and 6 kg m⁻³. Sources of Fe and Mn were pre-plant Micromax, liquid sulfate salts, and liquid chelates applied in the irrigation water. No difference in growth between micronutrient sources was detected, however, growth was greater at the 3 and 6 kg m⁻³ lime rates. Levels of Fe and Mn in medium solution and tissue decreased with increasing lime rate, with availability of Fe and Mn greatest with chelate as the source, regardless of lime rate. A similar study was conducted with a control and liquid sulfate treatment. There was no difference in dry weight between the sulfate treatment and the control, except at 0 kg m⁻³ lime where the control plants were larger. Again, lime additions increased growth, and Fe and Mn availability in medium solution and tissue levels decreased. These results suggest that if Fe and Mn additions are needed, all sources provide adequate Fe and Mn for growth.
M.S.

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8

Asad, Adil. "External and internal boron requirements of plants using boron buffered solution culture." Thesis, Asad, Adil (1998) External and internal boron requirements of plants using boron buffered solution culture. PhD thesis, Murdoch University, 1998. https://researchrepository.murdoch.edu.au/id/eprint/52442/.

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In soils and in conventional nutrient solutions, establishing the internal and external boron (B) requirements of plants is often confounded because the external B concentration changes during plant growth. On the other hand, the major problem of working with low B concentrations in conventional nutrient solutions is that these concentrations are quickly depleted as B is taken up by the plant roots. Hence in most conventional solution cultures, the initial B concentration is often very high to ensure adequate supply of B throughout an experiment. This research was carried out to develop a solution culture system in which the free B concentration would be buffered at constant concentrations, ranging from low to high. This developed B-buffered solution culture system was then tested as a means of determining the internal and external B requirements of different plant species. Further experiments were conducted to study the external and internal B requirements of plants at different growth stages, and to study distribution of B in different plant parts by using the above B-buffered solution culture system. The B specific resin, Amberlite IRA 743, which complexes H3BO3 on its Nmethyl glucamine functional groups, was chosen for this study because the B saturated resin maintained a realistic equilibrium B concentration in solution and there was no evidence that the resin had significant effects on plant growth other than in releasing and equilibrating B in the nutrient solution. The resin released nitrogen (N) into solution but, provided an adequate solution N supply was maintained, there were no indirect effects of the resin on plant growth apart from its control of B solution concentration. The B sorption capacity of the resin varied from 2.2 to 5.0 mg B/g resin. Boron saturated resin maintained an equilibrium solution B concentration of 46 μM when added at the rate of 2 g of resin to 1L of B-free triple deionised water. Plants grown in complete nutrient solution with B-saturated resin added at 1 g per litre of nutrient solution grew as well as plants grown in conventional nutrient solution containing 9.2 μM B and their shoots contained adequate B concentrations for growth. Glasshouse experiments were undertaken to establish buffered B concentrations ranging from deficient to adequate in nutrient solutions. Supplying different amounts of B saturated resin, Amberlite IRA 743, per unit solution volume; and loading the resin with B at 1 to 100 % of full saturation resulted in solution B concentrations (μM) ranging from 0.17 to 2.9 and from 0.05 to 27.0, respectively. The latter method was more effective in producing a wide range of B supply, from deficiency to adequacy. By this method critical external and internal B concentrations at vegetative growth of canola were 0.6 fjM B and 6-8 mg B kg dry weight, respectively. At solution B concentrations from 0.04 to 0.3 μm, canola (Brassica napus L.) plants remained alive but both shoot and root growth were stunted with classical B deficiency symptoms. Increasing solution B concentrations progressively increased B concentrations in shoots and roots. In roots, B concentrations were less than one-third of those in lower shoots and less than those in upper shoots, except in B-deficient plants. At 0.04 μM B, plants absorbed no B from solution. Increasing solution B concentrations from 0.1 to 26.5 μM increased relative B uptake rates from 0.005 to 0.1 μ mole g root fresh weight day . Maximum root efficiency, defined as relative uptake rate divided by the solution B concentration, was achieved at 0.04 to 0.3 μM B in solution. With increasing solution B concentrations, relative uptake rates of calcium decreased from 248 to 10 μ mole g-1 root fresh weight day-1. The results suggest that B specifically inhibited calcium absorption or accelerated calcium efflux. Canola was grown to flowering in a subsequent experiment to study the effect of external B concentration, established with B-loaded resin, on the distribution of B in plants and to investigate the external B concentrations for near maximum vegetative and reproductive growth. Mean B concentrations in B-buffered nutrient solutions ranging from 0.36 to 46.6 μM were achieved by loading B-specific resin at 4 to 100 % of full saturation. At low levels of B, the resin maintained constant B in nutrient solutions from Day 0 to 55. When relative growth rates for the periods 0-10, 10-22 and 22-55 DAT were related to mean external B concentration, the critical external B concentration for the growth period of 0-55 DAT remained unchanged with time and plant growth stage. Boron concentrations in shoots and roots increased strongly with increasing solution B concentrations up to 1-2 μM B and then more weakly with increases in solution B above 2 μM B. At deficient to marginal external B concentrations, stems had higher B concentrations than leaf blades on Days 10 and 22 but not at Day 55. Although the plants at low external B (< 0.45 μM) concentrations had some vegetative growth they did not produce reproductive parts compared to the plants with adequate B. At the flowering stage, maximum B concentration was found in florets and growth of these plant parts was more sensitively depressed by low B than vegetative plant parts. At 0.86 μM B in nutrient solutions, plants achieved maximum vegetative dry matter and flowered normally. Plants supplied with < 0.45 μM B produced no flowers or flowers were abnormal with aborted stamens and pistils. At 0.35 μMB, plants, whilst stunted, continued to produce vegetative dry matter though reproductive growth was completely suppressed. At flowering higher B concentrations occurred in the flowers (50.3 mg/kg dry weight) than in leaf (19.9 mg/kg dry weight), stem (19.0 mg/kg dry weight) or root (14.7 mg/kg dry weight). This study suggested that external B requirements for canola at the reproductive stage is 0.86 μM for maximum or near to maximum growth. External and internal B requirements of three plant species were studied using the B-buffered solution culture technique. In a glasshouse solution culture experiment, B concentrations were buffered with B saturated resin (Amberlite IRA 743); and loading the resin with B at 1 to 100 % of full saturation. Average B concentrations (μM) in nutrient solutions ranged from 0.04-28.3. The external and internal B requirements of a monocot (wheat, Triticum aestivum), a herbaceous dicot (sunflower) and a woody dicot (marri Corymbia calophylla) were examined using the buffered culture system. Plants were harvested after 10 and 20 days (wheat and sunflower) or 20 and 40 days (marri). At low external B (< 0.13 μM), growth of marri and sunflower was severely depressed, whereas the growth of wheat plants was only weakly depressed at 0.04 pM B in solutions. Where maximum dry weight of shoots was obtained, B concentrations (mg/kg) in leaf blades at the first harvest were 17.9, 19.7 and 1.2, for marri, sunflower and wheat, respectively. Results of this experiment suggested that the two dicotyledons marri and sunflower have higher external and internal B requirements than wheat. Increasing solution B from 0.05 to 28.5 μM increased relative B uptake rates from 0.43-1.02, 0.64-0.94 and 0.02-0.07 μ mole g-1 root dry weight day -1 in the case of marri, sunflower and wheat, respectively. Thus, the higher internal and external B requirements of sunflower and marri compared to wheat were supported by higher rates of B absorption. In conclusion, the B-buffered solution culture system developed in this study has considerable potential for B nutrition studies of plants. This system is robust and easy to establish. Whilst B-specific resin supplied B to canola till flowering stage at higher B loadings (> 16% of full B saturation of resin) it did not maintain constant B concentrations for more than 22 days growth. The length of time for which effective buffering of solution B was achieved appeared to vary with rate of biomass accumulation which, in turn, was a function of time of year and plant species. It is suggested that buffered B concentrations in nutrient solutions may be achieved for experiments of long duration either by increasing the amounts of resin per unit nutrient solution or replacing the B-specific resin after every 8-10 days.

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Parks, Sophie Emma, University of Western Sydney, and Faculty of Science and Technology. "Proteaceae nutrition and the phosphorus requirements of Banksia ericifolia L.f." THESIS_FST_xxx_Park_S.xml, 2000. http://handle.uws.edu.au:8081/1959.7/103.

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The basic mineral nutritional requirements of Proteaceae are not well understood.They are generally assumed to require low levels of nutrients and be susceptible to nutrient (especially Phosphorus) toxicity.This project aimed to estimate the general nutritional requirements of Proteaceae for optimum growth, with special emphasis on the Phosphorus requirement. Potted plants were grown in soilless growth media with controlled release fertiliser and were watered according to need in a naturally lit greenhouse. The nutrient requirements of Proteaceae were found to vary among species but were not lower than the reported requirements for the Ericaceae, another heath family. The variables of growth media and plant development were found to be important factors affecting the critical Phosphorus concentration and need consideration in the derivation of the Phosphorus requirement of Banksia ericifolia.
Doctor of Philosophy (PhD)

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Parks, Sophie Emma. "Proteaceae nutrition and the phosphorus requirements of Banksia ericifolia L.f. /." View thesis View thesis, 2000. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030429.105120/index.html.

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Thesis (Ph.D.) -- University of Western Sydney, 2000.
"A thesis submitted in fulfilment of the requirement for the degree of Doctor of Philosophy, Horticulture, University of Western Sydney, Australia, December 2000" Bibliography : leaves 206-230.

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Kazemi, Hossein V. "Estimating crop water requirements in south-central Kansas." Thesis, Kansas State University, 1985. http://hdl.handle.net/2097/9859.

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Farr, Chuck. "Yield Requirements of Non-Premium Durum Wheat." College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/200542.

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Hahne, Kathryn S., and Ursula K. Schuch. "Nitrogen Requirements of Prosopis Velutina during Early Seedling Growth." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/216532.

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The objective of this study was to determine the optimum rate of N to maximize growth of Prosopis velutina seedlings and minimize N leaching when seedlings were grown in different substrates. Mesquite seedlings were grown in sand or soilless media and were fertigated with a solution of67 % NH₄⁺: 33 % NO₃⁻ at a rate of 25, 50, 100, or 200 mg N/L. After 60 days, plants in media produced 41 % more leaves and total biomass compared to those in sand. Leaf number was greatest for plants grown at 200 mg N/L in both substrates. Root biomass of plants in media showed no response to increasing N concentrations while root biomass of seedlings in sand were similar for the three lower N concentrations and nearly doubled for the highest one. Shoot biomass of seedlings receiving 25, 50, or 100 mg N/L was similar, but more than doubled for plants fertigated with 200 mg N/L. N leachate losses were highest from seedlings growing in sand and receiving the two higher N fertigations, those in media had greatest N leachate loss when fertigated at 200 mg N/L.

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Alhajhouj, Al-Gahtany Mohammed Refdan. "An investigation into the optimum chemical and physical requirements of peat-based substrates when used in small volume plugs." Thesis, University of Reading, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391350.

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Tewolde, Haile. "Seasonal gas exchange rates and growth of pearl millet (Pennisetum americanum (L.) Leeke); across a gradient of drought." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184684.

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Seasonal patterns of stomatal activity, plant-temperature-based drought stress indices, growth and grain yield of two pearl millet (Pennisetum americanum (L.) Leeke) parental lines and their F₁ hybrid were studied under a sprinkler irrigation gradient system in 1985 and 1986 in Tucson, Arizona. Physiological and morphological measurements of stressed and nonstressed plants were made periodically starting at the panicle initiation stage. Well-defined trends in stomatal conductance (Cg), transpiration (Tr), and photosynthetic (Pn) rates of nonstressed plants were observed over the seasons. Tr increased from 5ug H₂O cm⁻²s⁻¹ at early panicle development stage to a peak of up to 30 ug cm⁻²s⁻¹ at flowering and declined to 10 ug cm⁻²s⁻¹ at maturity. Pn of well-irrigated plants was highest (26 uMoles CO₂ m⁻²s⁻¹) at early flag leaf appearance stage and declined slowly to 14 uMoles m⁻²s⁻¹ at maturity. In extremely stressed plants, Cg, Tr and Pn were highest early in the seasons, lowest in the middle of the seasons, and slightly increased towards the end of the seasons. The seasonal trends in stomatal response depended on the stage of plant growth and vapor pressure deficit of the air. Transpiration efficiency was highest at partial stomatal closure. Morphologically, the F₁ hybrid was more like its male than its female parent. The female parent produced less dry matter, had thinner leaves and greater ratio of leaf to stem dry matter, and yielded less grain than the other genotypes. The results indicated that leaf:stem ratio can be a useful selection criterion of drought avoiding genotypes. Plants that develop stems and heads rapidly (low leaf:stem ratio) are more desirable under stress than plants that tend to become leafy. Decreases in Tr, Pn, dry matter and grain yield due to stress could be assessed with canopy or leaf temperature, canopy minus air or leaf minus air temperature, and crop (CWSI) or leaf (LWSI) water stress indices. CWSI and LWSI were more desirable in assessing stress than the other indices. CWSI is effective in assessing the magnitude of stress in a crop stand, while LWSI may be useful in situations where use of the infrared thermometer is difficult.

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Janat, Mohamad Mussaddak. "Phosphorus fractions, movement and fertilizer requirements of grapes grown on White House soil." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184754.

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A two-year fertilizer study on a mature vineyard of Vita vinifera, C. V. Cabernet Sauvignon and Sauvignon blanc, has been conducted on White House sandy loam (fine, mixed, thermic Ustollic Haplargid), at Page Ranch, International Agricultural Center. Furthermore, eleven different varieties grown at Page Ranch and treated with different levels of nitrogen fertilizer were tested for total P content in plant tissue and NO₃-N. Moreover, in another site with similar soil, a Cabernet Sauvignon grown at the Vina Sonoita Vineyard was treated with both soil and foliar applications of P fertilizer, and was tested for total P content in plant tissue. Soil phosphorus (P) fractions of the White House soil were determined in order to evaluate the various forms of soil P and determine the most important form which contributes most to the availability index. The objectives of this study were to study the various inorganic P forms of White House soil, compare two methods of extracting available P (Olsen and Bray P.), and examine the relationships between soil pH, extractable Al, Fe, Mn, and Zn with the availability index of soil P. Furthermore, the effect of P rates and placement on the P status of plant tissue, grape yield, wine quality and petiole-P to blade-P ratio had been investigated. Three different placements of surface, 25 and 50 cm depth at rates of 88 g of P and 80 g of N per vine, were in RCB design in 1987. In 1988, three P rates of 0, 88, and 176 g of P and 207.5 g N per vine, and the two mentioned varieties CS and SB were arranged in RCB design with factorial type. The results showed that placements did not have a significant effect of P status in plant tissue and grape yield. Yet grapes showed a significant response to P fertilizer in terms of increasing P content in plant tissues and grape yield. Petiole P to Blade P ratios were calculated for the CS, and SB grown at Page Ranch, as well as for CS grown at Sonoita vineyard. This ratio is a good indicator for diagnosis of P status in a given vineyard. Nitrogen stress had its clear and profound effect on P content of grape petioles.

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17

Sumardi, of Western Sydney Hawkesbury University, of Agriculture Horticulture and Social Ecology Faculty, and School of Horticulture. "The influence of water stress on flowering and fruit production of Capsicum annuum Longum (chilli peppers)." THESIS_FAHSE_HOR_Sumardi_X.xml, 1993. http://handle.uws.edu.au:8081/1959.7/82.

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Severe water stress reduced the number of flowers produced by Capsicum annuum var. annuum L. Longum plants, but the timing of flower production was less affected. The use of different plant establishment techniques modified flower production. Bare rooted transplants slowed the rate of flower production in comparison with direct seeded plants or those established from cell tray transplants. Bare rooted transplants delayed the onset of water stress. The capabilities of male and female gametophytes were reduced by water stress, with the female more affected, and the interaction of male and female gametophytes was affected by moderate water stress. Moderate water stress increased the time to fruit set, but affected neither the number nor percentage of fruit set, whereas severe water stress increased the time and reduced the number and percentage. Severe water stress reduced the number and percentage of mature fruit, fruit quality indices and total fruit yield. Moderate water stress reduced the number of seeds per fruit and fruit dry weight, but total fresh weight yield was not significantly affected. The time to fruit set was negatively correlated with the quality indices of mature fruit, whereas the number of seeds was positively correlated with the same. Fertilisation determined the success of seed set, and the rapidity of fruit set. Successful fertilisation can only occur when the pollen tube arrives at a viable ovule. The processes of pollen tube growth and longevity of the ovule are the factors most critically affected by water stress in determining the yield of C. annuum Longum.
Master of Science (Hons)

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18

Ledezma, Razcon Eugenio A. "MODELING OF THE BIOELECTRIC SYSTEM FORMED BY PALLADIUM AND CARBON ELECTRODES INSERTED IN COTTON (GOSSYPIUM HIRSUTUM) PLANTS." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275289.

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19

Tipton, J. L. "Pregermination Treatments and Temperature Requirements for Germination of Mexican Redbud, Evergreen Sumac, and Mealy Sage Seeds." College of Agriculture, University of Arizona (Tucson, AZ), 1989. http://hdl.handle.net/10150/216060.

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Scarification and stratification requirements of Mexican redbud and evergreen sumac seeds and the effects of temperature on Mexican redbud evergreen sumac, and mealy sage seed germination were investigated. The maximum predicted germination from a quadratic response surface was 94.9% after 62 minutes scarification and 35 days stratification for Mexican redbud and 59.3% after 52 minutes scarification and 73 days stratification for evergreen sumac. Mexican redbud seeds germinated from 23.8 to 30.5 C, evergreen sumac from 20.8 to 30.6 C, and mealy sage from 20.6 to 34.2 C. Maxium predicted final percent germination and the temperature at which it occurred for Mexican redbud, mealy sage, and evergreen sumac was 104.2 at 27.5 C, 89.8 at 29.2 C, and 42.4 at 22.1 C, respectively

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Doerge, T. A., and M. J. Ottman. "Predicting Late Season Nitrogen Fertilizer Requirements of Irrigated Durum Wheat Using Stem Nitrate Analyses." College of Agriculture, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/201347.

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A field experiment was conducted on a Casa Grande sandy loam at the Maricopa Agricultural Center to 1) determine the optimum rates of late season N needed to achieve optimum yield and quality of irrigated dumm wheat in conjunction with varying rates of early season N, and 2) to evaluate the usefulness of stem NO₃⁻N analysis in predicting the late season N rates which optimize grain production but minimize the potential for nitrate pollution of groundwater. The application of 80, 195 and 350 lbs. N/a during vegetative growth resulted in wheat with deficient, sufficient and excessive N status at the boot stage as indicated by stem NO₃⁻N analysis. The application of 60 lbs. N/a at heading to N-deficient wheat and 15 lbs. N/a to N-sufficient wheat resulted in grain protein levels above 14% but had little effect on grain yield. Applications of N at heading to wheat which had previously received excessive N did not affect grain yield or quality. The use of stem NO₃⁻N analysis appears to be a useful tool in predicting the minimum N rate to be applied during the early reproductive period to insure acceptable levels of grain protein at harvest.

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21

Silva, José Mauro Santana da [UNESP]. "Crescimento de mudas de Pinus oocarpa Schiede em diferentes condições hídricas e de adubação." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/103423.

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Made available in DSpace on 2014-06-11T19:32:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-06-21Bitstream added on 2014-06-13T20:43:45Z : No. of bitstreams: 1 silva_jms_dr_botfca.pdf: 435059 bytes, checksum: 94166d93f0c927f7d4158f3aa6ca96ab (MD5)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Universidade Estadual Paulista (UNESP)
The aim of this work was to compare the final development of Pinus oocarpa Schiede seedlings using tree different underwater depth and with or without coverage fertilization. The research was done inside on a glass green house at the UNESP - College of Agronomical Science, Rural Engineering Department (Botucatu - SP - Brazil). Two trials were done to evaluate biomass, seedling height and diameter development. The first trial, using underground water on 17 cm, 31 cm and 45 cm depth, with or without coverage fertilization with N-P-K. The second trial was done with 28 flowerpots (12 liters each) and 3 seedlings per unit. The experimental design, used to evaluate the height and diameter growth and hydric potential and relative plant water content, was: 1- without water deficit and without coverage fertilization; 2- with water deficit and without coverage fertilization; 3- without water deficit and with coverage fertilization; 4- with water deficit and coverage fertilization. The underground water result showed that 31 cm and fertilization was better for seedling growing rather that 17 cm and without fertilization. The fertilized treatments showed higher plant high and diameter comparing to non fertilized samples, using Tukey test at 5%. For dry plant matter, the best results were obtained with 31 and 45 cm underground water level. The seedling root system dry mass was decrement along the soil profile. The treatment with underground water of 31 cm and fertilization was superior according to Tukey test at 5% of probability and the treatment with underground water of 17 cm and without fertilization was inferior for root dry mass (g). All the others treatment didn t have statistical differences. It didn t happen the irrigation effect on the plant high development; however the fertilized treatment had superior development compared to unfertilized samples. The relative water content didn t change... (Complete abstract click electronic access below)

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22

Wongareonwanakij, Sathaporn. "Effects of water stress and partial soil-drying on senescence of sunflower plants." Title page, contents and summary only, 1995. http://web4.library.adelaide.edu.au/theses/09A/09aw872.pdf.

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Bibliography: leaves 98-123. This thesis investigates the symptoms of leaf senescence in response to plant shoot water stress and demonstrates the effect of a non-hydraulic root signal in the senescence response of mature leaves of sunflower. The alleviation of the leaf soluble protein loss rate by excision of the root system in drying soil indicates that this signal originates in roots in dry soil and acts to promote protein loss.

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23

Clark, Lee J., E. Niel Biggs, and Laura Rose. "Wheat Water Requirements and Typical Irrigation Efficiences in the Safford Area." College of Agriculture, University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/200511.

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24

Duckwitz, Daniel [Verfasser]. "Power System Inertia : Derivation of Requirements and Comparison of Inertia Emulation Methods for Converter-based Power Plants / Daniel Duckwitz." Kassel : Universitätsbibliothek Kassel, 2019. http://d-nb.info/1190050145/34.

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25

Mitchell, Patrick John. "From conduits to communities : plant water use strategies and evapotranspiration in a semi-arid ecosystem in south-western Australia." University of Western Australia. School of Plant Biology, 2009. http://theses.library.uwa.edu.au/adt-WU2010.0034.

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[Truncated abstract] Understanding the ecohydrological dynamics of native vegetation can provide a benchmark for future efforts to restore landscape hydrology and allow predictions of potential landscape responses to climate uncertainty and associated changes in vegetation cover. The key drivers of evapotranspiration (Et) involved in maintaining a hydrological balance that minimises deep drainage in semi-arid ecosystems operate at a range of scales, and in this thesis I assessed the water relations of functionally and taxonomically diverse plant communities in south-western Australia from the leaf-level to ecosystem scale. For three key communities; heath shrubland, mallee (small multistemmed eucalypt) -heath, and open eucalypt woodland, populating a typical catenary sequence of soil types along a slope, I addressed the following questions: 1) What are the predominant water use strategies of wheatbelt native plant communities and what underlying trade-offs determine the distribution of plant water use strategies along the topographical gradient? 2) What are the roles of soil water and hydraulic limitation in controlling the spatial and temporal dynamics of transpiration in different functional types? 3) What is the magnitude and partitioning of total Et in the woodland community and what processes determine Et fluxes on a seasonal and annual basis? 4) What are the seasonal differences in Et among contrasting community-types and how do these patterns relate to canopy attributes and transpiration capacity along the topographical gradient? A key philosophical step in working with species-rich communities was to develop the concept of 'hydraulic functional types' (HFTs) to identify groupings of species using associations of physiological and morphological traits that define their hydrological functioning. .... However, as shallow soils dried during spring and summer, Et fluxes were significantly lower at the heath site (0.35 versus 0.66 mm day-1 for the woodland in February), demonstrating that the seasonality of Et fluxes differentiates communityscale contributions to regional water balance. Land-surface exchange of water over native vegetation is by no means uniform, but varies according to the spatial and temporal availability of water along topographical gradients. In general, shallow soils present fewer opportunities for water use partitioning and favour drought hardiness and a transpiration response that tracks recent rainfall patterns, whereas deeper soils promote greater differentiation in water use strategy and support canopies responsive to atmospheric demand. This thesis provides a unique description of ecosystem water balance in a global biodiversity hotspot by viewing complex vegetation mosaics in terms of their relevant hydrological units. This information is fundamental to sustainable agroforestry and revegetation efforts and our ability to gauge possible changes in vegetation structure and function under a changing climate.

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26

Semon, Mande 1957. "Interplot and intraplot border effects on maize genotypes under two levels of moisture availability." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276817.

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The performance of three maize (Zea mays L.) hybrids, grown under two irrigation levels, was used to investigate the effects of soil moisture competition between adjacent plots, the transmission of these effects into multi-row adjacent plots and types of multi-row plots and plot borders most effective in shielding from these interplot competition effects. On the basis of grain yield, competition effects intended to the second rows of five-row plots necessitating more than five-row plots to accurately evaluate the full transmission of interplot competition effects into adjacent plots. Evaluation of genotypes in one-row plots all with the same common border row genotype to make them three-row plots would be more suitable for evaluation of relative competitiveness for soil moisture under soil moisture stress conditions compared to no border rows or border rows of the same genotype being evaluated.

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27

Papadopoulos, Anastasios K. "Nitrogen and moisture distributions under subirrigated soybeans." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55520.

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A field lysimeter experiment was conducted on a sandy loam soil during the 1990 and 1991 growing seasons. The experiment tested the effects of different watertables on soybean yields, and on moisture distribution and nitrogen concentration of the soil profile. The watertable depths were 40, 60, 80, and 100 centimeters (cm).
Yields were measured in terms of number of beans per plant, number of pods per plant, number of beans per pod, and seed protein content at harvest.
Soil samples collected at depths of 30 and 70 cm from the soil surface were analyzed for moisture content and NO$ sb3 sp-$-N and NH$ sb4 sp+$-N concentrations.
The experimental results showed that controlled watertable management increased the yield and decreased soil NO$ sb3 sp-$-N levels. The best results from the watertables tested were found to be at 60 and 80 cm. This is suggested as the range of watertable depths that should be maintained for optimum soybean production.

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Silva, José Mauro Santana da 1967. "Crescimento de mudas de Pinus oocarpa Schiede em diferentes condições hídricas e de adubação /." Botucatu : [s.n.], 2007. http://hdl.handle.net/11449/103423.

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Orientador: Antonio Evaldo Klar
Banca: João Carlos Cury Saad
Banca: Magali Ribeiro da Silva
Banca: Marcio da Silva Araújo
Banca: Geraldo Gonçalves dos Reis
Abstract: The aim of this work was to compare the final development of Pinus oocarpa Schiede seedlings using tree different underwater depth and with or without coverage fertilization. The research was done inside on a glass green house at the UNESP - College of Agronomical Science, Rural Engineering Department (Botucatu - SP - Brazil). Two trials were done to evaluate biomass, seedling height and diameter development. The first trial, using underground water on 17 cm, 31 cm and 45 cm depth, with or without coverage fertilization with N-P-K. The second trial was done with 28 flowerpots (12 liters each) and 3 seedlings per unit. The experimental design, used to evaluate the height and diameter growth and hydric potential and relative plant water content, was: 1- without water deficit and without coverage fertilization; 2- with water deficit and without coverage fertilization; 3- without water deficit and with coverage fertilization; 4- with water deficit and coverage fertilization. The underground water result showed that 31 cm and fertilization was better for seedling growing rather that 17 cm and without fertilization. The fertilized treatments showed higher plant high and diameter comparing to non fertilized samples, using Tukey test at 5%. For dry plant matter, the best results were obtained with 31 and 45 cm underground water level. The seedling root system dry mass was decrement along the soil profile. The treatment with underground water of 31 cm and fertilization was superior according to Tukey test at 5% of probability and the treatment with underground water of 17 cm and without fertilization was inferior for root dry mass (g). All the others treatment didnt have statistical differences. It didnt happen the irrigation effect on the plant high development; however the fertilized treatment had superior development compared to unfertilized samples. The relative water content didnt change... (Complete abstract click electronic access below)
Doutor

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29

Sumardi. "The influence of water stress on flowering and fruit production of Capsicum annuum Longum (chilli peppers)." Thesis, View thesis View thesis, 1993. http://handle.uws.edu.au:8081/1959.7/82.

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Severe water stress reduced the number of flowers produced by Capsicum annuum var. annuum L. Longum plants, but the timing of flower production was less affected. The use of different plant establishment techniques modified flower production. Bare rooted transplants slowed the rate of flower production in comparison with direct seeded plants or those established from cell tray transplants. Bare rooted transplants delayed the onset of water stress. The capabilities of male and female gametophytes were reduced by water stress, with the female more affected, and the interaction of male and female gametophytes was affected by moderate water stress. Moderate water stress increased the time to fruit set, but affected neither the number nor percentage of fruit set, whereas severe water stress increased the time and reduced the number and percentage. Severe water stress reduced the number and percentage of mature fruit, fruit quality indices and total fruit yield. Moderate water stress reduced the number of seeds per fruit and fruit dry weight, but total fresh weight yield was not significantly affected. The time to fruit set was negatively correlated with the quality indices of mature fruit, whereas the number of seeds was positively correlated with the same. Fertilisation determined the success of seed set, and the rapidity of fruit set. Successful fertilisation can only occur when the pollen tube arrives at a viable ovule. The processes of pollen tube growth and longevity of the ovule are the factors most critically affected by water stress in determining the yield of C. annuum Longum.

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30

Doerge, T., T. Knowles, and M. Ottman. "Evaluation of the Accuracy of a Wheat Stem Nitrate Test in Predicting Nitrogen Requirements of Irrigated Durum Wheat." College of Agriculture, University of Arizona (Tucson, AZ), 1988. http://hdl.handle.net/10150/200815.

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The procedure currently recommended by the University of Arizona for predicting the nitrogen (N) requirements of durum wheat has proven to be quite accurate at sites where grain yields exceeded 5,400 lbs/acre. However, the method slightly overestimated N needs when the yield possibility was below that level. Additional information on the relationships between N rates, stem NO₃⁻N levels and grain yields are needed for the wide range of agronomic conditions found in Arizona. Three N fertility trials were conducted at the Maricopa Agricultural Center to: 1) document the accuracy of the currently recommended soil + stem NO₃⁻N testing procedure in predicting the N needs of durum wheat on soils of varying residual N content and grain yield potentials; and 2) to evaluate the use of the current stem testing procedure on two durum varieties 'Aldura' and 'Westbred -881. The University of Arizona procedure was found to accurately predict the minimum amount of N required for optimum production of durum wheat on two sites where yield potentials were 5,400 and 4300 lbs. grain /A, but it slightly overpredicted N rates on two sites with maximum yield levels of 5,400 lbs /a. 'Aldura' consistently out yielded 'Westbred -881' by about 12 % but 'Aldura' also averaged 0.78 %lower in grain protein content. Little statistical or practical differences were observed in the quantities of NO₃⁻N contained in the stem tissue of these two varieties, which should simplify the interpretation of stem NO₃⁻N values for various wheat cultivars. The currently recommended procedure for predicting optimum N rates in durum wheat production has proven to be accurate when yield levels exceed 5,400 lbs. grain /A. A slight modification of the procedure may be needed to more closely predict N requirements on lower yielding sites.

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31

Weideman, Craig Ivan. "Linking satellite and point micrometeorological data to estimate : distributed evapotranspiration modelling based on MODIS LAI, Penman-Monteith and functional convergence theory." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1012078.

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Recent advances in satellite sensor technology and micrometeorological instrumentation for water flux measurement, coupled with the expansion of automatic weather station networks that provide routine measurements of near-surface climate variables, present new opportunities for combining satellite and ground-based instrumentation to obtain distributed estimates of vegetation water use over wide areas in South Africa. In this study, a novel approach is tested, which uses satellite leaf area index (LAI) data retrieved by the Moderate Resolution Imaging Spectroradiometer (MODIS) to inform the FAO-56 Penman-Monteith equation for calculating reference evaporation (ET₀) of vegetation phenological activity. The model (ETMODIS) was validated at four sites in three different ecosystems across the country, including semi-arid savanna near Skukuza, mixed community grassland at Bellevue, near Pietermaritzburg, and Groenkop, a mixed evergreen indigenous forest near George, to determine potential for application over wider areas of the South African land surface towards meeting water resource management objectives. At Skukuza, evaluated against 170 days of flux data measured at a permanent eddy covariance (EC) flux tower in 2007, the model (ETMODIS) predicted 194.8 mm evapotranspiration relative to 148.9 mm measured fluxes, an overestimate of 31.7 %, (r² = 0.67). At an adjacent site, evaluated against flux data measured on two discrete periods of seven and eight days in February and May of 2005 using a large aperture scintillometer (SLS), ETMODIS predicted 27.4 mm and 6.7 mm evapotranspiration respectively, relative to measured fluxes of 32.5 and 8.2 mm, underestimates of 15.7 % and 18.3 % in each case (r² = 0.67 and 0.34, respectively). At Bellevue, evaluated against 235 days of evapotranspiration data measured using a surface layer scintillometer (SLS) in 2003, ETMODIS predicted 266.9 mm evapotranspiration relative to 460.2 mm measured fluxes, an underestimate of 42 % (r² = 0.67). At Groenkop, evaluated against data measured using a SLS over three discrete periods of four, seven and seven days in February, June and September/October respectively, ETMODIS predicted 9.7 mm, 10.3 mm and 17.0 mm evapotranspiration, relative to measured fluxes of 10.9 mm, 14.6 mm and 23. 9 mm, underestimates of 22.4 %, 11.2 % and 24.1 % in each case (r² = 0.98, 0.43 and 0.80, respectively). Total measured evapotranspiration exceeded total modelled evapotranspiration in all cases, with the exception of the flux tower site at Skukuza, where evapotranspiration was overestimated by ETMODIS by 31.7 % relative to measured (EC) values for the 170 days in 2007 where corresponding modelled and measured data were available. The most significant differences in measured versus predicted data were recorded at the Skukuza flux tower site in 2007 (31.7 % overestimate), and the Bellevue SLS flux site in 2003 (42 % underestimate); coefficients of determination, a measure of the extent to which modelled data are able to explain observed data at validation periods, with just two exceptions, were within a range of 0.67 – 0.98. Several sources of error and uncertainty were identified, relating predominantly to uncertainties in measured flux data used to evaluate ETMODIS, uncertainties in MODIS LAI submitted to ETMODIS, and uncertainties in ETMODIS itself, including model assumptions, and specific uncertainties relating to various inputs; further application of the model is required to test these uncertainties however, and establish confidence limits in performance. Nevertheless, the results of this study suggest that the technique is generally able to produce estimates of vegetation water use to within reasonably close approximations of measurements acquired using micrometeorological instruments, with r² values within the range of other peer-reviewed satellite remote sensing-based approaches.

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32

Kosiba, Andrea. "Effects of irradiation and temperature on shoot growth and development in Blue holly (Ilex x meserveae) /." SLU Alnarp : Department of Crop Science, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/200541.pdf.

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33

Doerge, T. A., T. C. Knowles, L. Clark, and E. Carpenter. "Effects of Early Season Nitrogen Rates on Stem Nitrate Levels and Nitrogen Fertilizer Requirements During Grain Filling for Irrigated Durum Wheat." College of Agriculture, University of Arizona (Tucson, AZ), 1989. http://hdl.handle.net/10150/201074.

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A field experiment was conducted on a Pima clay loam at the Safford Agricultural Center to: 1) determine the optimum rates of late season N needed to achieve optimum yield and quality of irrigated durum wheat in conjunction with varying rates of early season N; and 2) evaluate the usefulness of stern NO₃-N analysis in predicting the late season N rates which optimize grain production but minimize the potential for nitrate pollution of groundwater. The application of 75, 175 and 350 lbs. N/a during vegetative growth resulted in wheat with deficient, sufficient and excessive N status at the boot stage, as indicated by stem NO₃-N analysis. The application of 60 lbs. N/a at heading to N- deficient wheat and 15-20 lbs. N/a to N-sufficient wheat resulted in grain protein levels above 14 %, but the applications had little effecton grain yield. Applications of N at heading to wheat which had previously received excessive N did not affect grain yield or quality. The use of stein NO₃-N analysis appears to be a useful tool in predicting the minimum N rate to be applied during the early reproductive period to insure acceptable levels of grain protein at harvest.

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34

DOMINICI, LAURA. "Phytotechnology & Design for Vertical Greening Systems.Light requirements for indoor applications and low-cost solutions for fostering their diffusion." Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2957759.

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35

Doerge, Thomas, Tim Knowles, Mike Ottman, and Lee Clark. "Predicting the Nitrogen Requirements of Irrigated Durum Wheat in Graham County Using Soil and Nitrate Analysis." College of Agriculture, University of Arizona (Tucson, AZ), 1987. http://hdl.handle.net/10150/203767.

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The high yielding spring wheats grown in Arizona usually require applications of fertilizer nitrogen (N) to achieve optimum grain yields and acceptable quality. The University of Arizona's currently recommended procedure (preplant soil plus periodic stem tissue analysis for NO₃-N to predict the N needs of wheat) is not widely used by Graham County growers for various reasons. A nitrogen fertility trial was conducted at the Safford Agricultural Center during the 1986-87 crop year to: 1) examine the relationships between basal stem nitrate-N levels, grain yields of durum wheat, and N fertilizer rates; and 2) to test the accuracy of the recommended procedure for predicting the N needs of durum wheat. Five rates of N from O to 419 lbs N /acre were applied in three split applications. One additional N treatment was made as indicated by the current University of Arizona procedure. Maximum grain yields of 5500 to 6200 lbs /a and protein levels in excess of 14.5% were attained with the application of at least 186 lbs NIA. An untimely early season irrigation induced a temporary N deficiency condition for all plots, which may have kept grain yields below the maximum yield possibility for this site. In spite of this, the amount of N predicted by the University of Arizona procedure (197 lbsN/acre) did attain an adjusted economic return which was not significantly different from the maximum numerical yield that was achieved for any of the other N treatments.

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36

Adkins, Lindsey M. "An alternative solution for water conservation using exotic plant species in the lower Kanawha Valley region and implemented in the design of an arboretum." Virtual Press, 2008. http://liblink.bsu.edu/uhtbin/catkey/1390309.

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Conserving the earth's precious water supply is of increasing importance in light of the growing population and climate dynamics; therefore, this study focuses on identifying those exotic species that are best suited for the changing climate and environment of the Lower Kanawha Valley Region in West Virginia without compromising the water sustainable qualities once exhibited by the indigenous species. This task was accomplished by reviewing, analyzing, and evaluating the plant hydraulics and habitat matching characteristics associated with the identified native and exotic species. These species were limited to those produced or found in the local nurseries and garden centers in the designated region, thereby providing a practical and water sustainable plant list for the local homeowners and design professionals. The final list of species was translated into a master planting design of an arboretum displaying and demonstrating water conservation on the grounds of the Hurricane Valley Park.
Department of Landscape Architecture

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37

Barry, Martin. "Distributed small-scale wind in New Zealand : advantages, barriers and policy support instruments : a thesis submitted to the Victoria University of Wellington in partial fulfilment of the requirements for the degree of Master of Environmental Studies /." ResearchArchive@Victoria e-Thesis, 2007. http://hdl.handle.net/10063/87.

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38

Warren, Daniel Cram. "Transpiration and conductance responses of salt-desert vegetaion in the Owens Valley of California in relation to climate and soil moisture." Diss., The University of Arizona, 1991. http://ezproxy.library.arizona.edu/login?url=.

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39

Kleinert, Aleysia. "The functional responses of phosphate-deficient lupin nodules as mediated by phosphoenolpyruvate carboxylase and altered carbon and nitrogen metabolism." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5184.

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Thesis (PhD (Plant biotechnology))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: In soils, the concentration of available phosphate (P) for plants is normally very low (ca. 1 µM in the soil solution), because most of the P combines with iron, aluminium and calcium to form relatively insoluble compounds. Inorganic P (Pi)-deficiency is thought to be one of the limiting factors of nitrogen fixation due to the high energy requirement for nitrogenase function of plants taking part in nitrogen fixation. Pideficiency has important implications for the metabolic Pi and adenylate pools of plants, which influence respiration and nitrogen fixation. An alternative route of pyruvate supply during Pi stress has been proposed involving the combined activities of phosphoenolpyruvate carboxylase (PEPc), malate dehydrogenase (MDH) and NAD-malic enzyme (ME) supplying pyruvate to the mitochondrion during Pi stress. Previously, three isoforms of PEPc were isolated from lupin nodules and roots, with two forms being nodule specific. The aim of this project was to determine the effect of Pi stress on these PEPc isoforms in Lupinus luteus at transcript and protein expression level with a view to produce genetically modified crops for nutrient-poor soils. Cytosolic P levels were measured over a time course to give an indication of temporal development of P stress in nodules. The changes in enzyme activities of PEPc, MDH and PK (pyruvate kinase) under P stress were measured and the downstream effect on amino and organic acid pools were analysed. Two novel PEPc isoforms, LUP1 (AM235211) and LUP2 (AM237200) were isolated from nodules, followed by transcriptional and protein expression analyses. Nodules under P stress had lower amounts of metabolically available Pi and as P stressed developed, the amount of Pi decreased. This decline in Pi levels was associated with lower growth, but higher biological nitrogen fixation (BNF). A greater proportion of root-nodule respiration was devoted to nutrient acquisition than to new growth. A typical P-stress response is higher anaplerotic carbon fixation via PEPc. However, in this study, no significant differences were found for PEPc, MDH or PK in P-stressed plants compared to P-sufficient plants which would lead to an increase in organic acids. An increase in key amino acids was reported along with unchanged levels of organic acids. These levels of organic and amino acid are in congruence with the increases in BNF under P-starvation. No significant differences were found in expression of PEPC1 or PEPC2 at 12 and 20 days for both P-sufficient and P-stressed plants which further supported the lack of engagement of the PEPc-MDH-ME bypass. PEPc activity appeared not to be regulated by gene expression or phosphorylation indicating that other posttranslational modifications such as a decrease in protein degradation may be of importance.
AFRIKAANSE OPSOMMING: Die konsentrasie van fosfaat (P) beskikbaar vir opname deur plante vanuit die grond is gewoonlik baie laag (in die omgewing van 1 µM) aangesien die P onoplosbare komplekse vorm met katione soos yster, aluminium en kalsium. ‘n Tekort aan anorganiese P (Pi) word gereken as een van die beperkende faktore van stikstofbinding as gevolg van die hoë energie behoefte wat nitrogenase plaas op plante wat van gefikseerde stikstof gebruik maak. Hierdie P-tekort het ook belangrike betrekking op die metaboliese fosfaat- en adenilaatpoele wat weer op hul beurt respirasie en stikstofbinding beÏnvloed. ‘n Alternatiewe roete van pirovaatvoorsiening aan mitochondria tydens fosfaatstres is voorgestel wat bestaan uit die aktiwiteite van fosfoenolpirovaat karboksilase (PEPc), malaat dehidrogenase en NAD-malaat ensiem. Vantevore is drie isovorme van PEPc uit Lupinus luteus wortelknoppies en wortels geïsoleer, met twee van die isovorme wat wortelknoppie-spesifiek was. The doel van hierdie projek was om die invloed van P-tekort op die transkripsie en proteien uitdrukkingsvlak van hierdie PEPc isovorme te bepaal met die doel van gemodifiseerde gewasse vir arm gronde ingedagte. Sitoplasmiese P konsentrasies is gemeet oor tyd om ‘n aanduiding te gee van die ontwikkeling van P-tekort oor tyd. Veranderinge in ensiemaktiwiteite van PEPc, MDH en pirovaatkinase (PK) is gemeet gedurende P-tekort as ook die moontlike effek van hierdie ensiemaktiwiteite op aminosuur en organiese suur poele. Twee nuwe PEPc isovorme, LUP1 (AM235211) en LUP2 (AM237200) is uit wortelknoppies geïsoleer en gekarakteriseer. Transkripsie en proteïenuitdrukking is geanaliseer. Wortelknoppies wat P-tekort behandeling ontvang het, het laer vlakke van metabolise beskikbare Pi gehad en soos die P-tekort ontwikkel het oor tyd, het die Pi vlakke gedaal. Hierdie afname in vlakke van Pi was geassosieer met laer groei, maar met ‘n toename in biologiese stikstofbinding. ‘n Groter proporsie van respirasie is toegestaan aan minerale opname as aan nuwe groei. ‘n Tipiese reaksie op P-tekort is hoër anaplerotiese koolstofbinding via PEPc. Alhoewel, in hierdie studie is geen gevind betekenisvolle verandering gevind in die aktiwiteite van PEPc, MDH en PK nie in plante wat P-tekort ervaar het nie. Verhoogde aktiwiteit van hierdie ensieme sou verhoogde organise suur konsentrasies tot gevolg hê. ‘n Toename in aminosuur konsentrasies is gevind tesame met onveranderde vlakke van organiese sure. Hierdie toename in aminosure word onderskryf deur die verhoogde biologiese stikstofbinding tydens P-tekort. Geen betekenisvolle verskille is gevind in die geenuitdrukking van pepc1 en pepc2 by beide 12 en 20 dae van P-tekort nie, wat verder die afwesigheid van die PEPc- MDH-ME alternatiewe roete beaam het. Dit blyk dat PEPc aktiwiteit nie deur geenuitdrukking of proteïenfosforilering beheer word nie, maar eerder dat ander posttranslasie modifikasies soos ‘n verlaagde afbraak van proteïen ‘n rol speel.

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Gannon, Eleanor. "Botanica the earthly divine : an exegesis submitted to Auckland University of Technology in partial fulfilment of the requirements for the degree of Master of Art and Design, 2009 /." Click here to access this resource online, 2009. http://hdl.handle.net/10292/805.

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Drawing inspiration from Dante Alighieri's Divine Comedy, this project seeks to incorporate the oxymetaphor, digital photography and photo manipulation into considerations of Heaven, Hell and Purgatory. By considering the potential of an earthly site of transition (the cemetery) in relation to Dante's divine spaces, these images consider certain contradictions existing between the cemetery as a manifestation of waiting, permanence, and decay, and its associations with temporality and transition. The cemetery is therefore an oxymoron. It suggests both a beginning and an end; growth and decay; a place of closure and a pace of transition. Although Heaven, Hell and Purgatory have distinct characteristics in these images, there are commonalities between their layered treatments and iconography that unify them as a whole.

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Gindaba, Jiregna. "Water and nutrient relations of selected tree species of Ethiopia." Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/16050.

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Dissertation (PhD (Bosb))--University of Stellenbosch, 2003.
ENGLISH ABSTRACT: This study was conducted to evaluate and compare the water and nutrient relations of three indigenous deciduous tree species, viz., Cordia africana Lam., Croton macrostachyus Del., Millettia ferruginea (Hochst.) Baker and two widely planted eucalypts, viz., Eucalyptus camaldulensis Dehnh and Eucalyptus globulus Labill from Ethiopia. The study was organized as glasshouse and field observations in Ethiopia. Owing to the lack of baseline studies on the water and nutrient relations of the deciduous tree species, the glasshouse experiments involved a wide range of water and nutrient applications. Seedlings were grown with the supply of various levels of water and nutrients during which gas exchange, water potential, relative water content, tissue nutrient content and biomass production were measured. The field observations were limited to the study of surface root distribution and leaf nutrient composition of mature trees and their effects on soil nutrient pool. The observations were made on isolated trees and mixed or pure stands of trees in Badessa area, Eastern Ethiopia. The field site was selected because of the availability of the study species and suitability of the trees for the study. In the glasshouse, increased water deficit significantly reduced predawn leaf water potential, relative water content, stomatal conductance, photosynthetic rate, whole plant water use efficiency, plant height, diameter, leaf area and biomass production. Both of the eucalypts did not grow faster than the deciduous species under well-watered conditions unlike under water stress conditions. C. macrostachyus and C. africana had higher transpiration rates and tissue nutrient accumulations than the other species. They also demonstrated higher biomass allocation to roots than all the other species to support the intensive water and nutrient uptake rate. Due to the ability to re-orient its leaves to avoid direct solar irradiance, M. ferruginea maintained higher tissue water potential and relative water content than all the other species under water stress regimes. The impact of imposed drought was quick and more damaging to the eucalypts compared to the deciduous tree species indicating that the eucalypts may not survive extreme drought conditions unlike the deciduous species that drop their leaves and may remain dormant for weeks. The current study gave new experimental proof that E. globulus was more vulnerable to drought than E. camaldulensis. Soil N stress resulted in an overall reduction of tissue N concentration, N:P ratio, photosynthetic rate, stomatal conductance and photosynthetic water use efficiency in all the species studied. Pants with high foliar nitrogen concentration had higher photosynthetic capacities indicating that N plays a key role in photosynthesis and growth of all the studied species. The current study showed that for all the tree species, more attention has to be given to soil N than to P as soil P had minor effects on the photosynthetic activities of plants of all species compared to N.The investigation on tissue nutrient composition confirmed that N:P ratio could be used to detect Plimitation in plants. However, N:P ratio could not distinguish between N-limitation and combined limitations of N and P. The study of isolated C. africana and C. macrostachyus trees on soils in Badessa, Eastern Ethiopia indicated improved soil N, P and K under tree canopies whereas no effects were observed on the other soil nutrients studied. Similar to glasshouse conditions, C. macrostachyus and C. africana produced extensive surface roots, interfering with crops grown in association. Due to their high nutrient cycling potential the net effect on soil was positive. Comparison of E. camaldulensis woodlot and a mixed stand composed of deciduous species indicated that the fine root biomass in the surface soil under E. camaldulensis was about three times that under the mixed stand. The fine root biomass of E. camaldulensis inside the stand and 10 meters away from the stand were comparable in the surface soils showing the presence of root competition with adjacent crops. Therefore, planting of E. camaldulensis in association or adjacent to croplands should be avoided. Nutrient and carbon pool of soil inside the mixed stand was generally higher than that of E. camaldulensis indicating that trees of the mixed stand recycled more nutrients to the soil.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die verskille tussen water- en voedingstofverhoudings van drie inheemse blaarwisselemde boomsoorte te vergelyk, viz., Cordia africana Lam., Croton macrostachyus Del., Millettia ferruginea (Hochst.) Baker en twee bekende eucalyptus spesies, viz., Eucalyptus camaldulensis Dehnh en Eucalyptus globulus Labil van Etiopië. Die studie het bestaan uit kweekhuis- en veldobservasies in Etiopië. As gevolg van beperkte navorsing ten opsigte van water- en voedingstofverhoudings in bladwisselende boomsoorte, het die kweekhuis-eksperimente bestaan uit 'n wye verkeidenheid water- en voedingstoftoetse. Saailinge is gegroei deur verskillende vlakke van water- en voedingstowwe by te voeg. Gaswisseling, waterpotensiaal, relatiewe hoeveelheid water, hoeveelheid voedingstowwe en produksie van biomassa is gemeet. Die veldobservasies was beperk tot oppervlak-wortelverspreiding en blaarvoedingstof hoeveelhede van volwasse bome, sowel as die effek op grondvoedingstowwe. Observasies was beperk tot geïsoleerde, gemengde en een spesie opstande, in die Badessa area, Oos Etiopië. Die studiearea was gekies op grond van die voorkoms van die gekose boomsoorte, sowel as die toepaslikheid van die bome vir die studie. In die kweekhuis is gevind dat die verhoogte watertekort die pre-sonop blaarwaterpotensiaal, relatiewe hoeveelheid water, stomatiese geleiding, fotosintetiese tempo, heelplant water-gebruikseffektiwiteit, plant hoogte, diameter, blaararea en biomassa produksie beduidend verminder het. Nie een van die eucalyptus spesies het vinniger as die bladwisselende spesies onder voldoende hidrasie gegroei nie. Dit was egter nie die geval onder die waterbeperkte toestande nie. C. macrostachyus en C. africana het ‘n hoër transpirasie tempo sowel as weefselvoedingstof waardes gehad as die ander spesies. Hierdie boomsoorte se wortelbiomassa was ook meer as die ander spesies, om vir die tempo van water- en voedingstofopname te akkomodeer. As gevolg van die vermoë om blare te kan oriënteer om direkte sonlig te vookom, het M. ferruginea ‘n hoër water-weefselpotensiaal en relatiewe waterinname gehad in vergelyking met die ander boomsoorte in beperkte water toestande. Die impak van gëinisieerde droogte het vinnig voorgekom en het meer skade aan die eucalyptus aangerig in vergelyking met die bladwisselende boomsoorte. Dit dui aan dat die eucalyptus-spesie nie ekstreme droogte kan oorleef nie, waar bladwisselende spesies hul blare laat afval en vir weke aan een dormant kan bly. Hierdie studie gee eksperimentele bewyse dat E. globulus minder bestand is teen droogte as E. camaldulensis. Beperkte N in die grond het veroorsaak dat daar ‘n algemene vermindering van weefsel Nkonsentrasie, N:P ratio, fotosintetiese tempo, stomatiese geleiding en fotosintetiese watergebruiks effektiwiteit in al die bestudeerde spesies was. Plante wat oor hoër blaar-stikstofkonsentrasiesbeskik, het hoër fotosintetiese kapasiteite wat aandui dat N ‘n belangrike rol in fotosintese en die groei van al die bestudeerde spesies speel. Die oorhoofse bevindings van die studie was, dat daar meer aandag gegee moet word aan grond-N as P omdat grond-P net ‘n kleiner rol speel in die fotosintetiese aktiwiteite van plante van al die spesies in vergelyking met N. Die ondersoek na weefselvoedingstof hoeveelhede het bewys dat die N:P ratio gebruik kan word om P-tekorte in plante aan te dui. Die N:P ratio kan egter nie die verskil in N-tekorte en gekombineerde tekorte van N en P aandui nie. Die studie van die geïsoleerde C. africana en C. macrostachyus bome op grondtipes in Badessa, Oos Etiopië het verbeterde grond-N, P en K onder kroondak gebiede getoon, daar was egter geen verskille in die ander grondvoedingstowwe wat bestudeer is nie. In toestande gelykstaande aan die van die kweekhuis, het C. macrostachyus en C. africana meer oppervlaksswortels ontwikkel. Die toename aan oppervlakswortels het ingedring op gewasse wat in assosiasie gegroei is, dit het egter ‘n positiewe effek op die grond gehad as gevolg van die hoë voedingstof-siklus-potensiaal. Die E. camaldulensis opstand is gevergelyk met ‘n gemengde opstand van bladwisselende spesies waar daar gevind is dat die fynwortel biomassa in die oppervlak grond onder die E. camaldulensis ongeveer drie keer soveel was as die van onder die gemengde opstand. Kompetisie met aangrensende gewasse is aangeui deurdat die fynwortel biomassa van E. camaldulensis binne die opstand en 10 meter weg van die opstand vergelykbaar was in die oppervlakgronde. Dit dui dus aan dat die plant van E. camaldulensis in assosiasie of aangrensend aan gewasse vermy moet word. Die teenwoordigheid van voedingstowwe en koolstof in die grond van die gemengde opstand was oor die algemeen hoër as die van die E. camaldulensis. Dit is ‘n aanduiding dat die bome van die gemengde opstand meer voedingstowwe aan die grond verskaf.

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Young, Laura May. "Masting and insect pollination in the dioecious alpine herb Aciphylla : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Biological Science in the University of Canterbury /." Thesis, University of Canterbury. Biological Sciences, 2006. http://hdl.handle.net/10092/1345.

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Aciphylla species (wild spaniard/speargrass) are an iconic component of the Australasian high country flora, but their reproductive system is enigmatic. They are insect-pollinated dioecious mast seeders (synchronous highly variable seed production), which seems maladaptive. The resource supply to pollinators is highly variable, yet dioecious plants are dependent on pollinators, and dioecious masting requires male and female plants to flower synchronously. Floral display in Aciphylla is relatively large, with tall inflorescences bearing thousands of flowers, suggesting that plants would not have the resources to produce such large stalks every year. But why do they have such huge inflorescences in the first place? I tested whether pollinator attraction is providing an economy of scale which favours intermittent production of very large inflorescences, by manipulating floral display size during a high-flowering year and measuring insect visitation rates and seed set (female reproductive success). Using space-for-time substitution and selective removal of male inflorescences, I also tested whether female seed set was affected by distance to flowering male plants (i.e. changes in local pollen availability) to see if flowering asynchrony would reduce pollination success. Bags were used to exclude pollination by insects and test for wind pollination, and hand pollination was done to test for pollen limitation. Insect surveys suggest that Aciphylla has a generalist pollination system (to avoid satiating a specialist pollinator during 'mast' years'). Male inflorescences received significantly more visits than females, and some seeds were set inside bags (although only 20-30%), suggesting wind pollination may occur at low levels. Seed set rate was higher for taller inflorescences with greater flowering length in A. aurea but tall inflorescences with excess flowers led to a decrease in seed set rates in A. scott-thomsonii. Hand pollination significantly increased seed set rates although these effects were not as large as expected (e.g. 10% increases from natural to hand-pollinated inflorescences were typical). There was no evidence for resource limitation in any species. Female plants in dense flowering populations had higher seed set rates, and individual floral display size in females was particularly important when females were 'isolated' from males. Insect visitation rates were generally higher on inflorescences with a larger floral display, suggesting that display size is important for pollinator attraction. Overall, these results suggest that the pollinator-attraction benefits of such a large floral display (at both the plant and population level) are possibly providing an economy of scale, although the relative effects are small.

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Ohta, Daisaku. "STUDIES ON THE SODIUM REQUIREMENT OF C[4] PLANTS." Kyoto University, 1988. http://hdl.handle.net/2433/78192.

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Pullan, M. R. "Plant population and sowing date in novel forms of combining peas." Thesis, University of Nottingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383719.

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Bleby, Timothy Michael. "Water use, ecophysiology and hydraulic architecture of Eucalyptus marginata (jarrah) growing on mine rehabilitation sites in the jarrah forest of south-western Australia." University of Western Australia. School of Plant Biology, 2003. http://theses.library.uwa.edu.au/adt-WU2004.0004.

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[Truncated abstract. Please see the pdf format for the complete text. Also, formulae and special characters can only be approximated here. Please see the pdf version for an accurate reproduction.] This thesis examines the water use, ecophysiology and hydraulic architecture of Eucalyptus marginata (jarrah) growing on bauxite mine rehabilitation sites in the jarrah forest of south-western Australia. The principal objective was to characterise the key environment and plant-based influences on tree water use, and to better understand the dynamics of water use over a range of spatial and temporal scales in this drought-prone ecosystem. A novel sap flow measurement system (based on the use of the heat pulse method) was developed so that a large number of trees could be monitored concurrently in the field. A validation experiment using potted jarrah saplings showed that rates of sap flow (transpiration) obtained using this system agreed with those obtained gravimetrically. Notably, diurnal patterns of transpiration were measured accurately and with precision using the newly developed heat ratio method. Field studies showed that water stress and water use by jarrah saplings on rehabilitation sites were strongly seasonal: being greatest in summer when it was warm and dry, and least in winter when it was cool and wet. At different times, water use was influenced by soil water availability, vapour pressure deficit (VPD) and plant hydraulic conductance. In some areas, there was evidence of a rapid decline in transpiration in response to dry soil conditions. At the end of summer, most saplings on rehabilitation sites were not water stressed, whereas water status in the forest was poor for small saplings but improved with increasing size. It has been recognised that mature jarrah trees avoid drought by having deep root systems, however, it appears that saplings on rehabilitation sites may have not yet developed functional deep roots, and as such, they may be heavily reliant on moisture stored in surface soil horizons. Simple predictive models of tree water use revealed that stand water use was 74 % of annual rainfall at a high density (leaf area index, LAI = 3.1), high rainfall (1200 mm yr-1) site, and 12 % of rainfall at a low density (LAI = 0.4), low rainfall (600 mm yr-1) site, and that water use increased with stand growth. A controlled field experiment confirmed that: (1) sapling transpiration was restricted as root-zone water availability declined, irrespective of VPD; (2) transpiration was correlated with VPD when water was abundant; and (3) transpiration was limited by soil-to-leaf hydraulic conductance when water was abundant and VPD was high (> 2 kPa). Specifically, transpiration was regulated by stomatal conductance. Large stomatal apertures could sustain high transpiration rates, but stomata were sensitive to hydraulic perturbations caused by soil water deficits and/or high evaporative demand. No other physiological mechanisms conferred immediate resistance to drought. Empirical observations were agreeably linked with a current theory suggesting that stomata regulate transpiration and plant water potential in order to prevent hydraulic dysfunction following a reduction in soil-to-leaf hydraulic conductance. Moreover, it was clear that plant hydraulic capacity determined the pattern and extent of stomatal regulation. Differences in hydraulic capacity across a gradient in water availability were a reflection of differences in root-to-leaf hydraulic conductance, and were possibly related to differences in xylem structure. Saplings on rehabilitation sites had greater hydraulic conductance (by 50 %) and greater leaf-specific rates of transpiration at the high rainfall site (1.5 kg m-2 day1) than at the low rainfall site (0.8 kg m-2 day1) under near optimal conditions. Also, rehabilitation-grown saplings had significantly greater leaf area, leaf area to sapwood area ratios and hydraulic conductance (by 30-50 %) compared to forest-grown saplings, a strong indication that soils in rehabilitation sites contained more water than soils in the forest. Results suggested that: (1) the hydraulic structure and function of saplings growing under the same climatic conditions was determined by soil water availability; (2) drought reduced stomatal conductance and transpiration by reducing whole-tree hydraulic conductance; and (3) saplings growing on open rehabilitation sites utilised more abundant water, light and nutrients than saplings growing in the forest understorey. These findings support a paradigm that trees evolve hydraulic equipment and physiological characteristics suited to the most efficient use of water from a particular spatial and temporal niche in the soil environment.

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Mahaman, Sabiou 1957. "Nitrogen requirements of grain sorghum (Sorghum bicolor (L.) Moench) under soil moisture stress." Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/277251.

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Water and fertilizers are the two major agricultural inputs limiting yields in the arid and semi-arid regions of the world. Proper knowledge of their influence on crops should be obtained for appreciable returns. Therefore, a field study was conducted to evaluate the effects of four nitrogen (N) treatments (0, 56, 112, and 168 kg N/ha), two water (M) levels (39 and 58 cm), and two varieties (V) (Funks G-522DR and Conlee Rusler) on dry matter production, total N concentration, and yield of grain sorghum (Sorghum bicolor (L.) Moench). Total N concentration, dry matter, and grain yield were increased by N treatments. Generally, the highest N rate gave the most significant effects; the other rates had statistically the same responses. Varieties were different in their dry matter and grain yields, but had the same total nitrogen contents, as was suggested by the ANOVA and means analysis. There were no detectable interactions among the factors. Moisture had minimal effect on dry matter and grain yields, but influenced total N concentration significantly. Nitrogen contents increased with the higher moisture level.

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Banks, Fiona Marjorie. "Genetic modification of photosynthesis to reduce plant requirements for nitrogen fertilisers." Thesis, Open University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301883.

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Boateng, Amma Serwah, and Narine Sargsyan. "Materialization and Management of Emergent Requirements of Key Stakeholders : A Case Study of Umeå Wastewater Treatment Plant Project." Thesis, Umeå universitet, Företagsekonomi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-98646.

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Stakeholder satisfaction has in the modern day, become an imperative criterion to achieve project success. Satisfaction of stakeholders’ requirements however is challenging because these requirements evolve as the project progresses. Previous research indicates that as stakeholders continuously interact with a project, they gain more information and new requirements or request for modifications are likely to emerge as a result of this increased intelligence. Nonetheless, conventional project management elicits requirements from stakeholders at the onset of the project, and uses these pre-defined requests to design the project. This practice hinders the ability of stakeholders to influence the project as it advances, and ill equips managers to handle and implement stakeholder requirements that materialize at subsequent phases. It is therefore important to investigate how emergent requirements of stakeholders come about and how they are managed in practice. The objective of this thesis is to answer the research question, “From the perspective of managers, in the Scandinavian management context, how do emergent requirements of key stakeholders materialize, and how are they managed?” by probing into the ways via which emergent requirement of stakeholders come about, and investigating how managers deal with these emergent requirement upon their occurrence. This qualitative study was conducted in the Scandinavian region using semi-structured interviews. Five respondents in managerial positions of the Umeå wastewater treatment plant project participated in the research and data collected concerned materialization and management of emergent requirements that surfaced during different phases of the project. The resulting data was then analyzed with reference to previously established theoretical frameworks. Results from this study confirm that, new or modified requirements and consequently, requests for changes do emerge at even the execution phase of projects, despite careful planning. These emergent requirements are traced to three different sources and are managed in different ways depending on the type of requirement, whether strategic and critical or minor.

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Silva, Joana Sequeira dos Ramos. "Planos de gestão de rega em projectos de arquitectura paisagista." Master's thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/4148.

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Mestrado em Arquitectura Paisagista - Instituto Superior de Agronomia
Irrigation is an essential factor for the success or failure of the landscape. The adequate design and functionality of an irrigation system is determinant to achieve the quality, economic and environmental targets of the landscape. This report starts with a historical outlook of the relevance of water in the landscape, from Antiquity to the present day, where there is a global crisis of water resources. This fact, along with the aesthetic and economic landscape concerns, is the main reason behind the great present interest on the application of Irrigation Management Plans to Landscape Architecture. In order to correctly manage a dynamical procedure such as irrigation, it is recognized that the best solution is to make use of a structured approach based on irrigation decision and efficiency programs. As a result, in this work an Irrigation Management Plan is considered as composed by four main stages, here described in detail: Planning, Scheduling, Monitoring and Evaluation. From this research we conclude in particular that an appropriate and continuously improved Irrigation Management Plan is the key for the successful achievement of any landscape project.

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Satchwell, Christa Elizabeth. "Investigation of the nutrient requirements of Pinus caribaea Morelet in vitro." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305742.

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Dissertations / Theses on the topic 'Plants Requirements'

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