Journal articles on the topic 'Terminal water deficit'
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Behrozi, M., Y. Emam, and K. Maghsoudi. "Responses of Six Wheat Cultivars to Terminal Water Deficit." Journal of Crop production and processing 5, no. 17 (December 1, 2015): 203–15. http://dx.doi.org/10.18869/acadpub.jcpp.5.17.203.
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CONESA, M. A., and J. GALMES. "Photosynthesis response to severe water deficit in terminal stems of Myriolimon ferulaceum." Photosynthetica 57, no. 4 (November 1, 2019): 921–30. http://dx.doi.org/10.32615/ps.2019.110.
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Zhang, Ji Cheng, Gui Xue Qi, and Jin Yu Lan. "Mathematical Model for the Economical Terminal Water Cut of Oil Well." Advanced Materials Research 616-618 (December 2012): 696–700. http://dx.doi.org/10.4028/www.scientific.net/amr.616-618.696.
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For an oil well, when its water cut rises to a certain high point, the economical input gets equal to the economical output, at this time, this oil well produces nothing economically. If the water cut exceeds this point, then this oil well produces a deficit. This point is the so-called economical terminal water cut. Based on the theory of break even analysis, this paper determined the components of the cost of an oil well, analyzed the factors affecting the economical terminal water cut of oil well and developed a mathematical model to predict the value of economical terminal water cut.
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Mitchell, J. H., G. J. Rebetzke, S. C. Chapman, and S. Fukai. "Evaluation of reduced-tillering (tin) wheat lines in managed, terminal water deficit environments." Journal of Experimental Botany 64, no. 11 (July 30, 2013): 3439–51. http://dx.doi.org/10.1093/jxb/ert181.
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Palta, J. A., and C. Ludwig. "Pod set and seed yield as affected by cytokinin application and terminal drought in narrow-leafed lupin." Australian Journal of Agricultural Research 48, no. 1 (1997): 81. http://dx.doi.org/10.1071/a96042.
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An individual flower-painting technique that utilises N6-benzylaminopurine (BAP) to increase pod set was used on an indeterminate cultivar of narrow-leafed lupin (Lupinus angustifolius L. cv. Merrit) and on a breeding line with restricted branching (84A/241) to examine the interaction between pod set, water deficit, and seed yield. Petals and sepals of each flower on each inflorescence were painted with a 0·002 M solution of BAP every day from the first day the flower opened to the day it senesced. A water deficit was induced, after flowering on the first-order apical branch, in half of the plants. The other half were maintained at a soil water content close to field capacity. Leaf water potential and leaf conductance declined and remained at about –1·25 MPa and 300 mmol/m2· s, respectively, in the treatments in which a terminal water deficit was induced. Application of BAP to flowers had no effect on plant-water relations. The water deficit reduced the number of pods that reached maturity (mature pods) when no BAP was applied and increased seed yield in pods that filled seeds. Application of BAP increased the number of pods that reached maturity. However, the additional pods that reached maturity produced unfilled seeds. Seed yield and harvest index were reduced in the BAP treatments, mainly as a result of a reduction in seed number. An increase in seed abortion during seed filling probably caused the reduction in seed number. We conclude that the reduction in seed number and pod filling resulted from a shortage of assimilates to fill all the mature pods produced.
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Hoelle, Julia, Folkard Asch, Awais Khan, and Merideth Bonierbale. "Phenology-Adjusted Stress Severity Index to Assess Genotypic Responses to Terminal Drought in Field Grown Potato." Agronomy 10, no. 9 (September 1, 2020): 1298. http://dx.doi.org/10.3390/agronomy10091298.
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Potato is a drought susceptible, often rain-fed crop suffering strongly from even short periods of soil water deficit. With global environmental conditions changing, potato clones resistant to variable water supply are needed and identifying them is a major task. Many indices assessing potato tolerance to water deficit have been proposed, albeit none of them takes into account the severity of the stress or the sensitivity of the developmental stage during which the stress occurs. As a result, data obtained on genotypes in one location or season are normally not useful in another location or in a different season. We have developed an index evaluating yield response of potato to water deficit based on the soil tension the genotype was subjected to for the duration of the stress modified by the development stage of the genotype. The sum of the daily values was combined in a stress severity index (SSI). In total thirteen genotypes differing in duration and sensitivity to drought were subjected to four levels of deficit irrigation on two soil types at different development stages over two years. Early drought (early tuber filling) reduced yields up to 95% whereas late drought (late tuber bulking) reduced yields significantly less. SSI depended on the genotypic phenological development and on the soil tension values and ranges between 25 and 3500. The index differentiated genotypic responses well across treatments and soil types, even with these relatively advanced development stages, up to a value of 1000. Beyond 1000, yields were generally reduced by more than 60% and a differentiation between genotypes was not possible anymore. SSI constitutes a method that renders site, location, year, season, and soil type effects comparable for responses of potato clones to soil water deficit. Combining this measure of stress severity with other proposed indices may improve upon their current weaknesses in finding or identifying the underlying traits of drought tolerance in potato.
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Janmohammadi, Mohsen, Farzaneh Asadi, Naser Sabaghnia, Amin Abbasi, Mojtaba Nouraein, and Fariborz Shekari. "The Effects of Foliar Feeding of Compatible Organic Solutes on Agronomic Traits of Safflower." Agriculture (Pol'nohospodárstvo) 63, no. 4 (December 1, 2017): 128–41. http://dx.doi.org/10.1515/agri-2017-0013.
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Abstract Safflower is originated from Iran and is tolerant against water deficit stress. However, in semi-arid Mediterranean climate terminal drought and heat stress adversely affect the safflower production. In order to investigate the influence of foliar application of proline (Pr) (10 and 20 mM) and glycinebetaine (GB) (2 and 4 mM) under well and deficit irrigation (37.23° N,46.16° E). Foliar spray of compatible organic solutes started from middle vegetative growth and continued till seed filling stage. Comparison of well irrigated and stress conditions revealed that severity of water deficit stress (SI) was 0.25. Evaluation of growth-related morphological characteristics such as plant height, leaf area, canopy spread and percent ground cover showed that they considerably reduced by water deficit stress. However, foliar application of compatible solutes could somewhat increase growth related parameters. Results showed that water deficit stress noticeably reduced the chlorophyll content, while foliar spray could alleviate the water deficit stress effects when compared with intact plant (non-sprayed plants). The beneficial effect of GB was more prominent than Pr, especially under deficit irrigation condition. Principal component analysis (PCA) indicated that the best performance under well irrigated condition was obtained by application of 4 mM GB while under deficit irrigation condition the best performance was recorded for plants treated with 2 and 4 mM GB and 20 mM Pr. Overall, results of current experiments showed that foliar spray with high concentration of GB may can significantly alleviate the adverse effects of water deficit stress.
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Kholová, Jana, Paul Zindy, Srikanth Malayee, Rekha Baddam, Tharanya Murugesan, Sivasakthi Kaliamoorthy, C. Tom Hash, et al. "Component traits of plant water use are modulated by vapour pressure deficit in pearl millet (Pennisetum glaucum (L.) R.Br.)." Functional Plant Biology 43, no. 5 (2016): 423. http://dx.doi.org/10.1071/fp15115.
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Traits influencing plant water use eventually define the fitness of genotypes for specific rainfall environments. We assessed the response of several water use traits to vapour pressure deficit (VPD) in pearl millet (Pennisetum glaucum (L.) R.Br.) genotypes known to differ in drought adaptation mechanisms: PRLT 2/89–33 (terminal drought-adapted parent), H 77/833–2 (terminal drought-sensitive parent) and four near-isogenic lines introgressed with a terminal drought tolerance quantitative trait locus (QTL) from PRLT 2/89–33 (ICMR01029, ICMR01031, ICMR02042, and ICMR02044). Plant water use traits at various levels of plant organisation were evaluated in seven experiments in plants exposed either transiently or over the long term to different VPD regimes: biomass components, transpiration (water usage per time unit) and transpiration rate (TR) upon transient VPD increase (g H2O cm–2 h–1)), transpiration efficiency (g dry biomass per kg H2O transpired), leaf expansion rate (cm per thermal time unit) and root anatomy (endodermis dimensions)). High VPD decreased biomass accumulation by reducing tillering, the leaf expansion rate and the duration of leaf expansion; decreased root endodermis cell size; and increased TR and the rate of TR increase upon gradual short-term VPD increases. Such changes may allow plants to increase their water transport capacity in a high VPD environment and are genotype-specific. Some variation in water use components was associated with terminal drought adaptation QTL. Knowledge of water use traits’ plasticity in growth environments that varied in evaporative demand, and on their genetic determinacy, is necessary to develop trait-based breeding approaches to complex constraints.
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Mohammadi, Soleiman, Reza Kas Nazani, Ayda Hosseinzadeh Mahootchi, and Keiwan Ftohi. "Variation of Water-Soluble Carbohydrates and Grain Yield in Iranian Cold Barley Promising Lines Under Well-Watered and Water Stress Conditions." Plant Breeding and Seed Science 68, no. 1 (October 28, 2014): 65–75. http://dx.doi.org/10.2478/v10129-011-0081-3.
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ABSTRACT In order to evaluate promising lines in terms of grain yield and water-soluble carbohydrates remobiliza-tion, an experiment with fifteen promising lines and two checks was carried out under full irrigation and terminal water stress conditions at Miyandoab Agricultural Research and Natural Resources Station. Mobilized dry matter content and remobilization percentage from shoot to grain under water deficit (177mg)(11.2%) were greater than those under well watering condition. The lowest (110 mg) and the highest (260mg) mobilized dry matter to grain were obtained for C-79-18 and C-83-15lines, respectively. Water deficit reduced grain yield of barley genotypes by 200-1600 kg/ha, and mean grain yield reduction was 800 kg/ha. Line 14 with 5.880and 5.300t/ha grain yield in favorable and water stress conditions was superior to the other lines. Under water deficit condition, line 14 had greater grain yieldby20% and 38% than the Bahman and Makouee cultivars, respectively. The results showed that greater grain yield in tolerant lines under water deficit was due to remobilization of unstructured carbohydrates from shoot to grain. Thus, it seems that selection of lines with higher translocated dry matter and contribution of pre-anthesis assimilate in grain filling under water stress, the suitable way for achieving genotypes with high grain yield under water stress condition.
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Likoswe, A. A., and R. J. Lawn. "Response to terminal water deficit stress of cowpea, pigeonpea, and soybean in pure stand and in competition." Australian Journal of Agricultural Research 59, no. 1 (2008): 27. http://dx.doi.org/10.1071/ar07155.
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The response to terminal water deficit stress of three grain legumes, soybean, cowpea and pigeonpea, was evaluated in plants grown in large tubes, in competition with either the same species or one of the other two species. The aim was to explore how species differences in drought response affected water use, growth and survival of plants in pure stand and in competition. Two plants, comprising the test species and its competitor, were grown in each tube. Water was withheld 26 days after sowing by which time each plant had at least three fully expanded trifoliolate leaves. Leaf water status and plant growth were measured through destructive samples when 80% and 90% of the estimated plant available water (PAW) was depleted and at plant death, while PAW depletion, node growth and leaf survival were monitored at 2–3 day intervals until the last plants died (61 days after water was withheld). In pure stand, the rate of PAW depletion was initially slowest in cowpea despite its much larger leaf area, and fastest in soybean. Node growth was most sensitive in cowpea, ceasing at 65% PAW depletion compared with 85% PAW depletion in pigeonpea and soybean, so that the latter two species produced relatively more nodes after water was withheld. However, senescence of the lower leaves was most rapid in soybean and slowest in cowpea. Cowpea and pigeonpea extracted almost all PAW and died an average 18 days and 14 days, respectively, after maximum PAW depletion. In contrast, soybean died before 90% of PAW was depleted and so in pure stand used less water. There were otherwise only minor differences between the species combinations in the timing and maximum level of PAW depletion. The ability of cowpea and pigeonpea to maintain leaf water status above lethal levels for longer was achieved through different means. Cowpea relied primarily on dehydration avoidance and maintained tissue water status higher for longer, whereas pigeonpea demonstrated greater dehydration tolerance. While significant levels of osmotic adjustment (OA) were identified in soybean and pigeonpea, OA appeared to be of limited benefit to leaf survival in soybean. Pigeonpea invested significantly more total dry matter (TDM) in roots than either cowpea or soybean. Cowpea survived longest in pure stand whereas pigeonpea and soybean survived shortest in pure stand, suggesting that the dehydration avoidance response of cowpea was more effective in competition with like plants whereas the dehydration tolerance strategies of pigeonpea and soybean were least effective when competing against like plants. On average, TDM per plant ranked in the order cowpea > soybean > pigeonpea, largely reflecting initial differences in plant size when water was withheld. However, there was an inverse relation between TDM of a species and that of its competitor, so that in effect, water not used by a given plant to produce TDM was used by its competitor and there were no differences in TDM production per tube.
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Sun, Xin, Cui-Qin Yang, Tao Wen, Fu-Chun Zeng, Qiang Wang, Wen-Yu Yang, and Hong-Hui Lin. "Water Stress Enhances Expression of Genes Encoding Plastid Terminal Oxidase and Key Components of Chlororespiration and Alternative Respiration in Soybean Seedlings." Zeitschrift für Naturforschung C 69, no. 7-8 (August 1, 2014): 300–308. http://dx.doi.org/10.5560/znc.2013-0181.
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Plastid terminal oxidase (PTOX) is a plastid-localized plastoquinone (PQ) oxidase in plants. It functions as the terminal oxidase of chlororespiration, and has the potential ability to regulate the redox state of the PQ pool. Expression of the PTOX gene was up-regulated in soybean seedlings after exposure to water deficit stress for 6 h. Concomitantly expression of the NDH-H gene, encoding a component of the NADPH dehydrogenase (NDH) complex which is a key component of both chlororespiration and NDH-dependent cyclic electron transfer (CET), was also up-regulated. Transcript levels of the proton gradient regulation (PGR5) gene, which encodes an essential component of the PGR5-dependent CET, were not affected by water stress, while the expression of the alternative oxidase (AOX1) gene, which encodes a terminal oxidase of alternative respiration in mitochondria, was also up-regulated under water stress. Therefore, our results indicate that water stress induced the up-regulation of genes encoding key components of chlororespiration and alternative respiration. Transcript levels of the AOX1 gene began to increase in response to water stress before those of PTOX suggesting that alternative respiration may react faster to water stress than chlororespiration.
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GONZÁLEZ, A., V. BERMEJO, and B. S. GIMENO. "Effect of different physiological traits on grain yield in barley grown under irrigated and terminal water deficit conditions." Journal of Agricultural Science 148, no. 3 (February 5, 2010): 319–28. http://dx.doi.org/10.1017/s0021859610000031.
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SUMMARYDrought is the main factor limiting the productivity of crops in Mediterranean areas. The introduction of physiological traits into crops that improve their tolerance to drought is necessary if yields under these conditions are to be efficiently improved. The effect of drought on different gas exchange variables, i.e. net photosynthesis (A), stomatal conductance (gs) and leaf chlorophyll concentration (Chl), and the relationship of these variables with yield were studied in 12 barley genotypes grown under irrigated and terminal drought conditions. The variable most sensitive to water deficit was gs (mean reduction 43% with respect to control conditions), followed by A (mean reduction 34%). The mean reduction of yield by terminal drought was 27%. A significant correlation was seen between these physiological traits and yield. The effect of water deficit on A, gs and Chl was smaller in the breeding lines than in the traditional varieties assayed, in agreement with the results found for yield. These results suggest a potential indirect selection of physiological characteristics in these breeding lines that allow greater tolerance to drought. The response of the different genotypes examined was not homogeneous across all the variables analysed. This variability is important in programmes aiming to obtain drought-tolerant genotypes via the optimization of traits such as those above.
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Fang, X. W., N. C. Turner, F. M. Li, and K. H. M. Siddique. "An early transient water deficit reduces flower number and pod production but increases seed size in chickpea (Cicer arietinum L.)." Crop and Pasture Science 62, no. 6 (2011): 481. http://dx.doi.org/10.1071/cp10349.
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Terminal drought is known to decrease flower production, increase flower and pod abortion, and decrease yield of chickpea (Cicer arietinum L.), but the effects of early-season drought have not been evaluated. The influence of an early transient water deficit on flower and pod production and abortion, and seed yield and its components was evaluated in two chickpea cultivars, Rupali, a desi type, and Almaz, a kabuli type. Thirty-six-day-old plants were subjected to: (i) a transient water deficit by withholding water for 35 days, and then rewatered (WS), and (ii) kept well watered (WW) throughout. In the WS treatment the soil water content, leaf relative water content and leaf photosynthetic rate decreased after water was withheld and, following rewatering, recovered to the WW level. Despite the WS treatment being imposed at different phenological stages in the two cultivars, WS reduced flower number per plant by ~50% in Rupali and Almaz, respectively, compared with the WW plants. In WW plants, ~15% of flowers aborted in both cultivars, and 42 and 67% of the pods aborted in Rupali and Almaz, respectively, whereas in WS plants, 18 and 23% of flowers aborted and 27 and 67% of pods aborted in Rupali and Almaz, respectively. While seed growth in WS plants of Rupali and Almaz occurred primarily after the plants were rewatered, the duration of seed growth decreased by 17 and 36 days, the maximum rate of seed filling increased by 3 times and 5 times, and seed size increased by 26 and 16%, respectively, compared with the WW plants. Seed yield per plant in WS plants decreased by 31% in Rupali and 38% in Almaz compared with the WW controls. The early transient water deficit decreased flower production, but improved flower and pod development; increased the rate of seed growth and increased final seed size; and had a smaller effect on seed yield compared with chickpea subjected to terminal drought.
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Bucci, Sandra J., Fabian G. Scholz, Guillermo Goldstein, Frederick C. Meinzer, Augusto C. Franco, Yongjiang Zhang, and Guang-You Hao. "Water relations and hydraulic architecture in Cerrado trees: adjustments to seasonal changes in water availability and evaporative demand." Brazilian Journal of Plant Physiology 20, no. 3 (September 2008): 233–45. http://dx.doi.org/10.1590/s1677-04202008000300007.
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We determined adjustments in physiology and morphology that allow Neotropical savanna trees from central Brazil (Cerrado) to avoid water deficits and to maintain a nearly constant internal water balance despite seasonal changes in precipitation and air saturation deficit (D). Precipitation in the study area is highly seasonal with about five nearly rainless months during which D is two fold higher compared to wet season values. As a consequence of the seasonal fluctuations in rainfall and D, soil water potential changes substantially in the upper 100 cm of soil, but remains nearly constant below 2 m depth. Hydraulic architecture and water relations traits of Cerrado trees adjusted during the dry season to prevent increasing water deficits and insure homeostasis in minimum leaf water potential ψL and in total daily water loss per plant (isohydry). The isohydric behavior of Cerrado trees was the result of a decrease in total leaf surface area per tree, a strong stomatal control of evaporative losses, an increase in leaf-specific hydraulic conductivity and leaf hydraulic conductance and an increase in the amount of water withdrawn from internal stem storage, during the dry season. Water transport efficiency increased in the same proportion in leaves and terminal stems during the dry season. All of these seasonal adjustments were important for maintaining ψL above critical thresholds, which reduces the rate of embolism formation in stems and help to avoid turgor loss in leaf tissues still during the dry season. These adjustments allow the stems of most Cerrado woody species to operate far from the point of catastrophic dysfunction for cavitation, while leaves operate close to it and experience embolism on a daily basis, especially during the dry season.
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Saradadevi, Renu, Helen Bramley, Jairo A. Palta, Everard Edwards, and Kadambot H. M. Siddique. "Root biomass in the upper layer of the soil profile is related to the stomatal response of wheat as the soil dries." Functional Plant Biology 43, no. 1 (2016): 62. http://dx.doi.org/10.1071/fp15216.
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Terminal drought is a common abiotic stress affecting wheat yield in Mediterranean-type environments. As terminal drought develops, top layers of the soil profile dry, exposing the upper part of the root system to soil water deficit while deeper roots can still access soil water. Since open stomata rapidly exhausts available soil water, reducing stomatal conductance to prolong availability of soil water during grain filling may improve wheat yields in water-limited environments. It was hypothesised that genotypes with more root biomass in the drying upper layer of the soil profile accumulate more abscisic acid in the leaf and initiate stomatal closure to regulate water use under terminal drought. The wheat cultivar Drysdale and the breeding line IGW-3262 were grown in pots horizontally split into two segments by a wax-coated layer that hydraulically isolated the top and bottom segments, but allowed roots to grow into the bottom segment. Terminal drought was induced from anthesis by withholding water from (i) the top segment only (DW) and (ii) the top and bottom segments (DD) while both segments in well-watered pots (WW) were maintained at 90% pot soil water capacity. Drysdale, initiated stomatal closure earlier than IGW-3262, possibly due to higher signal strength generated in its relatively larger proportion of roots in the drying top segment. The relationship between leaf ABA and stomatal conductance was strong in Drysdale but weak in IGW-3262. Analysis of ABA metabolites suggests possible differences in ABA metabolism between these two genotypes. A higher capability of deeper roots to extract available water is also important in reducing the gap between actual and potential yield.
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KAMARA, A. Y., A. MENKIR, B. BADU-APRAKU, and O. IBIKUNLE. "The influence of drought stress on growth, yield and yield components of selected maize genotypes." Journal of Agricultural Science 141, no. 1 (August 2003): 43–50. http://dx.doi.org/10.1017/s0021859603003423.
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The risk of drought is high in the Sudan savannah zone of West and Central Africa because rainfall in this area is unpredictable in quantity and distribution. Thus, improved maize genotypes tolerant to drought could stabilize maize grain yield in this zone, where recurrent drought threatens grain production. Six maize genotypes, two each of hybrids, open-pollinated varieties (OPVs) and landraces, were evaluated for tolerance to terminal water deficit before flowering. Water deficit significantly reduced growth, grain yield and yield components of the maize genotypes. Significant differences were observed among genotypes for all the traits measured. One hybrid, 9011-30, and two improved OPVs, STR-EV-IWD and IYFD-C0, that showed tolerance to water stress recorded higher grain yield, and accumulated and partitioned more assimilates to the grain than the drought-susceptible genotypes. Also the drought-tolerant genotypes, 9011-30, STR-EV-IWD and IYFD-C0 had more ears/plant and greater numbers of kernels/ear. These genotypes could serve as sources of drought tolerance for the development and improvement of new drought-tolerant maize genotypes.
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CARR, M. K. V., and C. M. MENZEL. "THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF LYCHEE (LITCHI CHINENSIS SONN.): A REVIEW." Experimental Agriculture 50, no. 4 (December 13, 2013): 481–97. http://dx.doi.org/10.1017/s0014479713000653.
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SUMMARYThe results of research into the water relations and irrigation requirements of lychee are collated and reviewed. The stages of plant development are summarised, with an emphasis on factors influencing the flowering process. This is followed by reviews of plant water relations, water requirements, water productivity and, finally, irrigation systems. The lychee tree is native to the rainforests of southern China and northern Vietnam, and the main centres of production remain close to this area. In contrast, much of the research on the water relations of this crop has been conducted in South Africa, Australia and Israel where the tree is relatively new. Vegetative growth occurs in a series of flushes. Terminal inflorescences are borne on current shoot growth under cool (<15 °C), dry conditions. Trees generally do not produce fruit in the tropics at altitudes below 300 m. Poor and erratic flowering results in low and irregular fruit yields. Drought can enhance flowering in locations with dry winters. Roots can extract water from depths greater than 2 m. Diurnal trends in stomatal conductance closely match those of leaf water status. Both variables mirror changes in the saturation deficit of the air. Very little research on crop water requirements has been reported. Crop responses to irrigation are complex. In areas with low rainfall after harvest, a moderate water deficit before floral initiation can increase flowering and yield. In contrast, fruit set and yield can be reduced by a severe water deficit after flowering, and the risk of fruit splitting increased. Water productivity has not been quantified. Supplementary irrigation in South-east Asia is limited by topography and competition for water from the summer rice crop, but irrigation is practised in Israel, South Africa, Australia and some other places. Research is needed to determine the benefits of irrigation in different growing areas.
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Faralli, Michele, Pier Lugi Bianchedi, Massimo Bertamini, and Claudio Varotto. "Rootstock Genotypes Shape the Response of cv. Pinot gris to Water Deficit." Agronomy 11, no. 1 (December 31, 2020): 75. http://dx.doi.org/10.3390/agronomy11010075.
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Understanding the physiological basis underlying the water stress responses in grapevine is becoming increasingly topical owing to the challenges that climate change will impose to grapevine agriculture. Here we used cv. Pinot gris (clone H1), grafted on a series of tolerant (1103Paulsen; P), sensitive (SO4) and recently selected (Georgikon28; G28, Georgikon121; G121, Zamor17; Z17) rootstocks. Plants were either subjected to reduced water availability (WS) or maintained at pot capacity (WW). Photosynthetic (light response curves), stomatal and in vivo gas exchange analysis were carried out as well as dynamics of daily water use (WU), leaf area accumulation with affordable RGB imaging pipelines and leaf water potential. Significant genotypic variation was recorded between rootstocks for most of the traits analyzed under optimal conditions with P and SO4 showing a more vigorous growth, higher CO2 assimilation rate, stomatal conductance and stomatal density per unit of leaf area than G28, G121, Z17 (p < 0.001). Under WS, rootstocks induced different water stress response in Pinot gris, with G28 and G121 showing a higher sensitivity of water use to reduced water availability (WS) (p = 0.021) and no variation for midday leaf water potential until severe WS. P, Z17 and to some extent SO4 induced a pronounced near-anisohydric response with a general WU maintenance followed by reduction in leaf water potential even at high levels of soil water content. In addition, G28 and G121 showed a less marked slope in the linear relationship between daily water use and VPD (p = 0.008) suggesting elevated sensitivity of transpiration to evaporative demand. This led to an insensitivity for total dry weight biomass of G28 and G121 under WS conditions (p < 0.001). This work provides: (i) an in-depth analysis for a series of preferable traits under WS in Pinot gris; (ii) a characterization of Pinot gris × rootstock interaction and a series of desirable traits under WS induced by several rootstocks; (iii) the potential benefit for the use a series of affordable methods (e.g., RGB imaging) to easily detect dynamic changes in biomass in grapevine and quickly phenotype genotypes with superior responses under WS. In conclusion, the near-isohydric and conservative behavior observed for G28 and G121 coupled with their low vigor suggest them as potential Pinot gris rootstock candidates for sustaining grapevine productivity in shallow soils likely to develop terminal stress conditions.
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Ebel, Robert C., Edward L. Proebsting, and Robert G. Evans. "Deficit Irrigation to Control Vegetative Growth in Apple and Monitoring Fruit Growth to Schedule Irrigation." HortScience 30, no. 6 (October 1995): 1229–32. http://dx.doi.org/10.21273/hortsci.30.6.1229.
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A standard fruit growth curve, used commercially as an aid to hand thinning, was compared to periodic volume measurements of apple fruit (Malus domestica Borkh. `Delicious') subjected to early season regulated deficit irrigation (RDI) to determine when to end RDI, which is used to control vegetative growth and save water. RDI suppressed stem water potential, stomatal conductance, and fruit growth rate compared to the trickle- and furrow-irrigated controls, which wetted about one-half and the entire soil volume, respectively. Full irrigation was restored to RDI trees by trickle and microsprinklers, which wetted about one-half and the entire soil volume, respectively, after terminal buds set. Stem water potential, stomatal conductance, and fruit growth rate of RDI trees increased to that of the controls, except for RDI/trickle trees, which had 80% the stomatal conductance of the other treatments. Fruit weight at harvest was affected by an interaction of irrigation treatment and cropload. RDI trees had similar or less vegetative growth and similar or higher yield efficiency than the controls. We recommend ending RDI before fruit growth declines below the standard curve.
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Vadez, Vincent, Jana Kholova, Mainassara Zaman-Allah, and Nouhoun Belko. "Water: the most important ‘molecular’ component of water stress tolerance research." Functional Plant Biology 40, no. 12 (2013): 1310. http://dx.doi.org/10.1071/fp13149.
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Water deficit is the main yield-limiting factor across the Asian and African semiarid tropics and a basic consideration when developing crop cultivars for water-limited conditions is to ensure that crop water demand matches season water supply. Conventional breeding has contributed to the development of varieties that are better adapted to water stress, such as early maturing cultivars that match water supply and demand and then escape terminal water stress. However, an optimisation of this match is possible. Also, further progress in breeding varieties that cope with water stress is hampered by the typically large genotype × environment interactions in most field studies. Therefore, a more comprehensive approach is required to revitalise the development of materials that are adapted to water stress. In the past two decades, transgenic and candidate gene approaches have been proposed for improving crop productivity under water stress, but have had limited real success. The major drawback of these approaches has been their failure to consider realistic water limitations and their link to yield when designing biotechnological experiments. Although the genes are many, the plant traits contributing to crop adaptation to water limitation are few and revolve around the critical need to match water supply and demand. We focus here on the genetic aspects of this, although we acknowledge that crop management options also have a role to play. These traits are related in part to increased, better or more conservative uses of soil water. However, the traits themselves are highly dynamic during crop development: they interact with each other and with the environment. Hence, success in breeding cultivars that are more resilient under water stress requires an understanding of plant traits affecting yield under water deficit as well as an understanding of their mutual and environmental interactions. Given that the phenotypic evaluation of germplasm/breeding material is limited by the number of locations and years of testing, crop simulation modelling then becomes a powerful tool for navigating the complexity of biological systems, for predicting the effects on yield and for determining the probability of success of specific traits or trait combinations across water stress scenarios.
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del Pozo, Alejandro, Nidia Brunel-Saldias, Alejandra Engler, Samuel Ortega-Farias, Cesar Acevedo-Opazo, Gustavo A. Lobos, Roberto Jara-Rojas, and Marco A. Molina-Montenegro. "Climate Change Impacts and Adaptation Strategies of Agriculture in Mediterranean-Climate Regions (MCRs)." Sustainability 11, no. 10 (May 15, 2019): 2769. http://dx.doi.org/10.3390/su11102769.
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The world’s five Mediterranean-climate regions (MCRs) share unique climatic regimes of mild, wet winters and warm and dry summers. Agriculture in these regions is threatened by increases in the occurrence of drought and high temperature events associated with climate change (CC). In this review we analyze what would be the effects of CC on crops (including orchards and vineyards), how crops and cropping and farming systems could adapt to CC, and what are the social and economic impacts, as well as the strategies used by producers to adapt to CC. In rainfed areas, water deficit occurs mostly during the flowering and grain filling stages (terminal drought stress), which has large detrimental effects on the productivity of crops. Orchards and vineyards, which are mostly cultivated in irrigated areas, will also be vulnerable to water deficit due to a reduction in water available for irrigation and an increase in evapotranspiration. Adaptation of agriculture to CC in MCRs requires integrated strategies that encompass different levels of organization: the crop (including orchards and vineyards), the cropping system (sequence of crops and management techniques used on a particular agricultural field) and the farming system, which includes the farmer.
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Krober, T., and P. M. Guerin. "Ixodid ticks avoid contact with liquid water." Journal of Experimental Biology 202, no. 14 (July 15, 1999): 1877–83. http://dx.doi.org/10.1242/jeb.202.14.1877.
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Larvae of the cattle tick Boophilus microplus and all life stages of the European sheep tick Ixodes ricinus avoid walking on a wet membrane surface surrounding a dry patch. Of 170 reactions made at a border with liquid water by 22 B. microplus larvae, 40% consisted of immediate turns to the opposite side to bring all the legs back onto a dry patch, 41% were walks along the border, during which the ticks maintained contact with both the dry and wet zones, and 19% were returns to the dry patch after a short excursion onto the wet surround. Since contact with one front leg tip was sufficient to cause return reactions from the wet surface in most of the border contacts, the water receptor(s) that enable ticks to perceive the wet surface are probably located in terminal pore sensilla on the first-leg tarsi. Observations on the return reactions of ticks with different groups of chemosensilla masked confirmed this. Ticks have an ambiguous relationship with water: they appear to avoid direct contact with it, but they need a high humidity to compensate for any deficit in body water.
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Dracup, Miles, Mark A. Reader, and Jairo A. Palta. "Variation in yield of narrow-leafed lupin caused by terminal drought." Australian Journal of Agricultural Research 49, no. 5 (1998): 799. http://dx.doi.org/10.1071/a97151.
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Narrow-leafed lupin is a rain-fed crop in southern Australia whose yields are limited by the amount and distribution of rainfall. Drought terminates the growing season, and the timing and intensity of development of this (terminal) drought is a likely cause of much yield variability. We investigated this yield variability by manipulating terminal drought with trickle irrigation. Despite comparatively high crop dry mass of nearly 9 t/ha in the absence of irrigation, seed yield was only 1·2 t/ha with a harvest index of only 14%. Delaying the terminal drought and thus prolonging the period for crop ripening raised crop dry mass by 18-42%, with large increases in harvest index and seed yields, which rose by 45-75% and 95-135%, respectively. Pod set started 110 days after sowing (DAS) but appreciable pod filling did not start until 140 DAS, by which time, in the unirrigated treatment, only about 15% of the plant-available soil water remained, leaf diffusive conductance had fallen by 75%, and leaf water potential was -1·7 MPa. Leaf senescence and abscission had already begun; in the control treatment only 25% of the green area remained at 150 DAS, when net vegetative growth ceased and appreciable seed filling began. During irrigation, plant-available soil water was maintained at 35-70% of that at field capacity, with correspondingly better plant water relations. Pod and seed filling started at the same times as in the unirrigated control, and vegetative growth ceased at the same time. However, green area declined more slowly and reproductive growth continued for longer and at a faster rate. Yields were highly correlated with the number of productive pods (and seeds) at maturity, which in turn was associated with pod survival rather than pod set. Irrigation increased the number of surviving pods and seeds, both of which sometimes aborted at comparatively late stages of filling. Average seed weights were stable across treatments, except where there was a period of drought before irrigation, in which case seeds were heavier, compensating for prior loss of pods. It is argued that a better ideotype for the Mediterranean environment of southern Australia would switch to reproductive growth earlier, before severe water deficit develops, and with less overlap between vegetative and reproductive growth.
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Davies, S. L., N. C. Turner, J. A. Palta, K. H. M. Siddique, and J. A. Plummer. "Remobilisation of carbon and nitrogen supports seed filling in chickpea subjected to water deficit." Australian Journal of Agricultural Research 51, no. 7 (2000): 855. http://dx.doi.org/10.1071/ar00018.
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In the Mediterranean-type environment of south-western Australia, pod filling of chickpea occurs when net photosynthesis and nitrogen fixation is low as a result of the onset of terminal drought. Remobilisation of carbon (C) and nitrogen (N) from vegetative parts to developing seed may be an important alternative source of C and N for seed filling. The contribution of stored pre-podding C and N to seed filling was studied by labelling the vegetative tissues with the stable isotopes, 13C and 15N, prior to podding and following their subsequent movement to the seed. In ICCV88201, an advanced desi breeding line, 9% of the C and 67% of the N in the seed were derived from pre-podding C and N in well-watered plants compared with 13% of the seed C and 88% of the seed N in water-stressed plants. Furthermore, the contribution of pre-podding C and N was higher for earlier set compared with later set seeds. Pre-podding C and N were derived predominantly from the leaves with relatively little from the stems, roots, and pod walls. Genotypic variation in remobilisation ability was identified in contrasting desi (Tyson) and kabuli (Kaniva) cultivars. In well-watered Tyson, 9% of the seed C and 85% of the seed N were remobilised from vegetative tissues compared with 7% of the seed C and 62% of seed N in well-watered Kaniva. Water deficit decreased the amount of C remobilised by 3% in Tyson compared with 66% in Kaniva, whereas the total amount of N remobilised was decreased by 11% in Tyson and 48% in Kaniva. This was related to the maintenance of greater sink strength in Tyson, in which the number of filled pods was reduced by 66% in stressed plants compared with a 91% decrease in Kaniva. This indicates that better drought tolerance in desi genotypes is partly a consequence of better remobilisation and higher pod number. These studies show that C and N assimilated prior to podding can supplement the supply of current assimilates to the filling seed in both well-watered and water-stressed chickpea. Remobilisation of pre-podding N is an essential source of N for seed filling irrespective of environmental stress.
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Lawn, R. J., and A. A. Likoswe. "Genotypic differences in leaf area maintenance contribute to differences in recovery from water stress in soybean." Australian Journal of Agricultural Research 59, no. 12 (2008): 1075. http://dx.doi.org/10.1071/ar08177.
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Genotypic effects on leaf survival during water deficit stress and subsequent recovery were evaluated using soybean plants grown in tall cylinders in the glasshouse. An initial experiment sought to verify reported genotypic differences in leaf area maintenance under severe water deficit stress. A second experiment sought to test the hypothesis that these putative differences might affect recovery after stress was relieved. Two shoot genotypes, G2120 and cv. Valder, reported to have high and low leaf area retention, respectively, were used in both experiments. In order to preclude the possibility that the reported differences between G2120 and Valder were related to root rather than shoot traits, each shoot was grafted at the cotyledonary stage onto 2 non-self root genotypes, cv. Leichhardt and PI416937. Leichhardt has an apparently normal root, while PI416937 has been reported to be ‘extensively fibrous-rooted’. In the first experiment, water was withheld at the first trifoliolate leaf stage and the plants subjected to terminal water deficit stress. Consistent with the previous report, leaf area was maintained for longer into the stress by the G2120 shoots, with rapid loss of lower leaves not starting until c. 90% of plant-available water (PAW) had been depleted, compared with c. 80% for Valder. The Valder leaves also showed more ‘firing’ damage, with large patches of dead leaf tissue on the retained leaves. Also consistent with the previous report, leaf epidermal conductance to water vapour was lower in G2120 than in Valder. There were no apparent root effects. In the second experiment, water was again withheld at the first trifoliolate leaf stage, and treatments were re-watered when 80%, 85%, 90%, and 95% of the estimated PAW was extracted. Again, G2120 shoots showed better leaf area maintenance during the drying cycle, and less firing damage. When the plants were re-watered, the re-growth of G2120 generally exceeded that of Valder at all levels of PAW depletion. The differences in recovery between G2120 and Valder shoots were sufficient to have agronomic relevance, and confirmed the hypothesis that leaf area retention can affect recovery after severe water deficit stress. Root effects were relatively small. During the drying cycle, leaflet growth was marginally enhanced by Leichhardt relative to PI416937 roots. After re-watering, there was stronger recovery of plants with PI416937 roots, especially those with G2120 shoots. The basis of the differences between the root genotypes is not known but the stronger recovery of PI416937 may reflect its putative ‘extensively fibrous’ nature.
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Belko, N., M. Zaman-Allah, N. N. Diop, N. Cisse, G. Zombre, J. D. Ehlers, and V. Vadez. "Restriction of transpiration rate under high vapour pressure deficit and non-limiting water conditions is important for terminal drought tolerance in cowpea." Plant Biology 15, no. 2 (July 23, 2012): 304–16. http://dx.doi.org/10.1111/j.1438-8677.2012.00642.x.
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Belko, Nouhoun, Mainassara Zaman-Allah, Ndiaga Cisse, Ndeye Ndack Diop, Gerard Zombre, Jeffrey D. Ehlers, and Vincent Vadez. "Lower soil moisture threshold for transpiration decline under water deficit correlates with lower canopy conductance and higher transpiration efficiency in drought-tolerant cowpea." Functional Plant Biology 39, no. 4 (2012): 306. http://dx.doi.org/10.1071/fp11282.
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As water availability is critical for reproduction, terminal drought tolerance may involve water-saving traits. Experiments were undertaken under different vapour pressure deficit (VPD) and water regimes (water stress (WS) and well watered (WW)) to test genotypic differences and trait relationships in the fraction of transpirable soil water (FTSW) at which transpiration declines, canopy conductance (proxied by transpiration rate (TR, g H2O cm–2 h–1)), canopy temperature depression (CTD, °C), transpiration efficiency (TE, g kg–1) and growth parameters, using 15 contrasting cowpea (Vigna unguiculata (L.) Walp.) genotypes. Under WW conditions at the vegetative and early podding stages, plant mass and leaf area were larger under low VPD, and was generally lower in tolerant than in sensitive genotypes. Several tolerant lines had lower TR under WW conditions and restricted TR more than sensitive lines under high VPD. Under WS conditions, transpiration declined at a lower FTSW in tolerant than in sensitive lines. Tolerant lines also maintained higher TR and CTD under severe stress. TE was higher in tolerant genotypes under WS conditions. Significant relationships were found between TR, and TE, CTD and FTSW under different water regimes. In summary, traits that condition how genotypes manage limited water resources discriminated between tolerant and sensitive lines. Arguably, a lower canopy conductance limits plant growth and plant water use, and allows tolerant lines to behave like unstressed plants until the soil is drier and to maintain a higher TR under severe stress, as lower TR at high VPD leads to higher TE.
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Pushpavalli, Raju, Mainassara Zaman-Allah, Neil C. Turner, Rekha Baddam, Mandali V. Rao, and Vincent Vadez. "Higher flower and seed number leads to higher yield under water stress conditions imposed during reproduction in chickpea." Functional Plant Biology 42, no. 2 (2015): 162. http://dx.doi.org/10.1071/fp14135.
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The reproductive phase of chickpea (Cicer arietinum L.) is more sensitive to water deficits than the vegetative phase. The characteristics that confer drought tolerance to genotypes at the reproductive stage are not well understood; especially which characteristics are responsible for differences in seed yield under water stress. In two consecutive years, 10 genotypes with contrasting yields under terminal drought stress in the field were exposed to a gradual, but similar, water stress in the glasshouse. Flower number, flower + pod + seed abortion percentage, pod number, pod weight, seed number, seed yield, 100-seed weight (seed size), stem + leaf weight and harvest index (HI) were recorded in well watered plants (WW) and in water-stressed plants (WS) when the level of deficit was mild (phase I), and when the stress was severe (phase II). The WS treatment reduced seed yield, seed and pod number, but not flower + pod + seed abortion percentage or 100-seed weight. Although there were significant differences in total seed yield among the genotypes, the ranking of the seed yield in the glasshouse differed from the ranking in the field, indicating large genotype × environment interaction. Genetic variation for seed yield and seed yield components was observed in the WW treatment, which also showed differences across years, as well as in the WS treatment in both the years, so that the relative seed yield and relative yield components (ratio of values under WS to those under WW) were used as measures of drought tolerance. Relative total seed yield was positively associated with relative total flower number (R2 = 0.23 in year 2) and relative total seed number (R2 = 0.83, R2 = 0.79 in years 1 and 2 respectively). In phase I (mild stress), relative yield of seed produced in that phase was found to be associated with the flower number in both the years (R2 = 0.69, R2 = 0.76 respectively). Therefore, the controlled drought imposition that was used, where daily water loss from the soil was made equal for all plants, revealed genotypic differences in the sensitivity of the reproductive process to drought. Under these conditions, the seed yield differences in chickpea were largely related to the capacity to produce a large number of flowers and to set seeds, especially in the early phase of drought stress when the degree of water deficit was mild.
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Yager, Phoebe H., Zerong You, Tao Qin, Hyung-Hwan Kim, Kazue Takahashi, Alan B. Ezekowitz, Gregory L. Stahl, Michael C. Carroll, and Michael J. Whalen. "Mannose Binding Lectin Gene Deficiency Increases Susceptibility to Traumatic Brain Injury in Mice." Journal of Cerebral Blood Flow & Metabolism 28, no. 5 (January 9, 2008): 1030–39. http://dx.doi.org/10.1038/sj.jcbfm.9600605.
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Mannose binding lectin (MBL) initiates complement activation and exacerbates tissue damage after systemic ischemia/reperfusion. We tested the hypothesis that MBL activates complement and worsens outcome using two levels of controlled cortical impact (CCI) in mice. After moderate CCI (0.6 mm depth), MBL immunostaining was detected on injured endothelial cells of wild-type (WT) mice and C3d was detected in MBL KO (deficient in MBL A/C) and WT mice, suggesting that MBL is dispensable for terminal complement activation after CCI. Brain neutrophils, edema, blood-brain barrier permeability, gross histopathology, and motor dysfunction were similar in injured MBL KO and WT mice. In mice subjected to mild CCI (0.2 mm), MBL KO mice had almost two-fold increased acute CA3 cell degeneration at 6 h ( P<0.01 versus WT). Naive MBL KO mice had decreased brain volume but performed similar to WT mice in two distinct Morris water maze (MWM) paradigms. However, injured MBL KO mice had impaired performance in cued platform trials (P<0.05 versus WT), suggesting a transient nonspatial learning deficit in injured MBL KO mice. The data suggest that MBL deficiency increases susceptibility to CCI through C3-independent mechanisms and that MBL-deficient patients may be at increased risk of poor outcome after traumatic brain injury.
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Vance, Nan C., and Steven W. Running. "Light reduction and moisture stress: effects on growth and water relations of western larch seedlings." Canadian Journal of Forest Research 15, no. 1 (February 1, 1985): 72–77. http://dx.doi.org/10.1139/x85-013.
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Ten-week-old western larch (Larixoccidentalis Nutt.) seedlings were grown in a greenhouse under 70, 37, and 27% full sunlight from late July to early October. In August, seedlings under each light treatment were repetitively water stressed until predawn leaf water potential (Bψ1) reached one of three levels: no stress (> −0.4 MPa), moderate stress (−0.7 to −1.0 MPa), and severe stress (−1.5 to −1.8 MPa). Moisture stressing significantly reduced height and diameter of seedlings grown under 70% light. Light reduction reduced shoot and root biomass accumulation. A positive linear relation was found between root dry weight and light intensity. The largest seedlings (on a weight basis) received the highest light, were unstressed, and had the lowest shoot/root ratios. Terminal bud set was not affected by light reduction or moisture stressing but occurred under a 14-h photoperiod and reduced nighttime temperatures. Stressed and shaded seedlings had significantly reduced diurnal K1 and stress-cycled seedlings showed an adjustment to stressing. The K1 of unstressed seedlings was correlated with humidity deficit (ABHD), and K1 of stressed seedlings, with Bψ1, and ABHD. Maximum K1 declined with decreasing Bψ1, but not to a level indicating complete stomatal closure.
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Janmohammadi, Mohsen, Hamid Mostafavi, and Naser Sabaghnia. "Effects of Enzymatic Biofertiliser on Growth and Yield of Lentil Genotypes under Deficit Irrigation/ Enzimatisko Biomçslojumu Ietekme Uz Daþâdu Lçcu Genotipu Augðanu Un Raþu Irigâcijas Trûkuma Apstâkïos." Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences. 68, no. 3-4 (August 1, 2014): 174–79. http://dx.doi.org/10.2478/prolas-2014-0020.
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Abstract Lentil (Lens culinaris Medic.) is one of the important pulse crops in semiarid agro-ecological zones with a Mediterranean-type climate. Terminal drought stress and poor plant nutrition are important factors limiting crop under these regions. The effects of enzymatic biofertiliser (MOG) application at sowing time or during reproductive stage on some morphological traits and yield components of eight lentil lines were evaluated under deficit-irrigation conditions at Maragheh (37°23' N; 46°16' E) in northwestern Iran. Results revealed that application of biofertiliser did not significantly affect most of the morphological traits. However, foliar application of MOG during early flowering stage somewhat increased 100-grain weight and grain yield and decreased the number of empty pod per plant. Moreover, the results indicated that there was significant diversity between lentil lines for the investigated traits. The best performance for grain yield was recorded for FLIP 86-35L. The overall lack of considerable response of lentil to the MOG treatments may suggest that the optimal efficiency of biofertiliser cannot be achieved under water scarcity conditions. Improvement in the adaptation of enzymatic fertilisers to semi arid regions with terminal drought stress requires to be increased.
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Cuevas-Velazquez, Cesar L., Gloria Saab-Rincón, José Luis Reyes, and Alejandra A. Covarrubias. "The Unstructured N-terminal Region ofArabidopsisGroup 4 Late Embryogenesis Abundant (LEA) Proteins Is Required for Folding and for Chaperone-like Activity under Water Deficit." Journal of Biological Chemistry 291, no. 20 (March 22, 2016): 10893–903. http://dx.doi.org/10.1074/jbc.m116.720318.
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Mohammadi, Hamid, Mohsen Janmohammadi, and Naser Sabaghnia. "Chlorophyll fluorescence response of wheat to exogenous application of growth regulators under terminal drought stress." Annales Universitatis Mariae Curie-Sklodowska, sectio C – Biologia 70, no. 1 (September 7, 2015): 13. http://dx.doi.org/10.17951/c.2015.70.1.13.
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<p>Drought stress negatively affects plant photosynthesis and disturbs the electron transport activity. Evaluation of the chlorophyll fluorescence parameters might reflect influence of the environmental stress on plants and can be applied as an indicator of the primary photochemistry of photosynthesis. In current study the effect of foliar application of benzylaminopurine (BAP, a synthetic cytokinin) and abscisic acid (ABA) on chlorophyll fluorescence parameters of relatively drought tolerant (Pishtaz) and susceptible (Karaj3) bread wheat genotypes under well watered and terminal water deficit condition have been evaluated. Terminal drought was induced by withholding water at anthesis stage (Zadoks scale 65). Results showed that coefficient of non-photochemical quenching of variable fluorescence (qN), quantum yield of PS II photochemistry (ΦPSII) and photochemical quenching (qP) were affected by hormone spray treatments. So that evaluation of parameters at 7 day after foliar treatments revealed that ABA significantly increased electron transport rate (ETR) and qN while considerably decreased ΦPSII, gs and maximum quantum yield of photosystem II (Fv/Fm). However exogenous application of cytokinin could increase gs, Fv/Fm and ΦPSII and the highest value of these parameters was recorded in <em>cytokinin </em>treated plants of Pishtaze cv. under well watered condition. Nevertheless, evaluation of the parameters in different periods after spraying showed that with approaching the maturity stage some traits like as gs, Fv/Fm and ETR significantly decreased in both genotypes. Evaluation of gs and Chlorophyll fluorescence parameters of genotypes between different irrigation levels showed that although cv. Pishtaz showed higher performance of PSII under well watered condition, it failed to maintain its superiority under stress condition. This finding suggests that some more responsive parameter like gs, Fv/Fm and ΦPSII can be considered as reliable indicator for understanding the biochemical and physiological effects of exogenous application of phytohormones under terminal drought stress.</p>
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Mahforojaki, Mehdi Savadkohi, Reza Talebi, and Sayyed Saeid Pourdad. "Analysis of tolerance indices for germplasm evaluation in safflower (Carthamus tinctorius L.) subjected to terminal drought stress." South Asian Journal of Experimental Biology 5, no. 5 (February 26, 2016): 156–61. http://dx.doi.org/10.38150/sajeb.5(5).p156-161.
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In order to evaluate quantitative drought resistance criteria in some safflower genotypes, fiftheen genotypes were evaluated both under moisture stress and non-stress field environments using a randomized complete block design for each environment. The genotypes showed significant differences in grain yield and other traits. Grain yield under irrigated conditions was adversely correlated with water deficit condition, suggesting that high potential yield under optimal conditions does not necessarily result in improved yield under stress conditions. Genotypes G64, G92 and PI253527 showed lower yield reduction than the average of other genotypes. Surprisingly, most of the genotypes showed more than 30% yield reduction under drought stress. The positive correlation between TOL and irrigated yield (Yp) and the negative correlation between TOL and yield under stress (Ys) suggest that selection based on TOL will result in reduced yield under well-watered conditions. We conclude that GMP and STI are able to discriminate tolerant group of genotypes under both environments. Therefore, genotypes G47, G64, G42 and S411 are superior genotypes for both environments. Genotypes S310 , S149 and Almaneriz are more suitable for non-moisture stress than moisture-stress environment.
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Chen, Cheng, Li Yao, Jing Cui, and Bao Liu. "Fisetin Protects against Intracerebral Hemorrhage-Induced Neuroinflammation in Aged Mice." Cerebrovascular Diseases 45, no. 3-4 (2018): 154–61. http://dx.doi.org/10.1159/000488117.
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Background: Fisetin is commonly used as an anti-inflammatory and neuroprotective drug. In this study, we aimed to investigate the efficacy of fisetin in alleviating intracerebral hemorrhage (ICH)-induced brain injury. Methods: Mouse ICH models were constructed using the collagenase-induction method. ICH mice received fisetin treatment at the dose of 10–90 mg/kg, followed by the evaluation of neurological deficit through neurologic severity scores (mNSS), brain water content and terminal deoxynucleotidyl transferase dUTP nick end labeling analysis of cell apoptosis. Cytokine levels were also assessed with enzyme-linked immunosorbent assay. The activation of astrocytes and microglia was evaluated through S100 staining and Western blot analysis of ionized calcium-binding adaptor molecule 1 respectively. Nuclear factor kappa-B (NF-κB) signaling was also evaluated by Western blot. Results: ICH mice demonstrated dramatic increase in mNSS, brain edema and cell apoptosis, indicating severe brain deficit. Fisetin treatment lowered these parameters, suggesting the alleviation of brain injury. Levels of proinflammatory cytokines were reduced, accompanied by a prominent decrease in activated astrocytes and microglia. NF-κB signaling was also attenuated by fisetin treatment. Conclusion: Fisetin effectively alleviates ICH by downregulating proinflammatory cytokines and attenuating NF-κB signaling. These data suggest fisetin as a valuable natural flavonol for clinical management of ICH-induced brain injury.
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Hochberg, Uri, Asfaw Degu, Tanya Gendler, Aaron Fait, and Shimon Rachmilevitch. "The variability in the xylem architecture of grapevine petiole and its contribution to hydraulic differences." Functional Plant Biology 42, no. 4 (2015): 357. http://dx.doi.org/10.1071/fp14167.
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Grapevine cultivars possess large variability in their response to water availability, and are therefore considered as a good model to study plant hydraulic adjustments. The current research compared the petiole anatomy of two grapevine (Vitis vinifera L.) cultivars, Shiraz and Cabernet Sauvignon, in respect to hydraulic properties. Hydraulic differences between the cultivar petioles were tested over 3 years (2011–2013). Anatomical differences, hydraulic conductivity and embolism were tested under terminal drought conditions. Additionally, xylem differentiation under well watered (WW) and water deficit (WD) conditions was compared. Shiraz was shown to possess larger xylem vessels that resulted in a significantly higher theoretical specific hydraulic conductivity (Kts), leaf hydraulic conductivity (Kleaf) and maximal petiole hydraulic conductivity (Kpetiole). Under WD, smaller vessels were developed, more noticeably in Shiraz. Results confirmed a link between petiole hydraulic architecture and hydraulic behaviour, providing a simple mechanistic explanation for the higher transpiration rates commonly measured in Shiraz. Smaller xylem vessels in Cabernet Sauvignon could imply on its adaptation to WD, and explains its better performances under such conditions.
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Spann*, Timothy M., Robert H. Beede, Steven A. Weinbaum, and Theodore M. DeJong. "Effect of Rootstock on Shoot Preformation and Neoformation in Pistachio cv. Kerman." HortScience 39, no. 4 (July 2004): 760C—760. http://dx.doi.org/10.21273/hortsci.39.4.760c.
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Rootstock significantly alters the pattern of shoot growth of pistachio (Pistacia vera) cv. Kerman. Trees on P. atlantica typically produce a single flush of spring growth whereas trees on P. integerrima selection PGI and P. atlantica × P. integerrima selection UCB-1 can produce multiple flushes during the season. Terminal buds of shoots on all three rootstocks were dissected during the dormant season to determine the number of preformed nodes. Data indicate that there are 8-9 nodes preformed in the dormant terminal bud of shoots from Kerman trees and that this number is independent of rootstock, canopy location, crop load, and shoot carbohydrate concentration, suggesting genetic control. This number corresponds with the number of nodes typically found on a shoot at the end of the spring growth flush. Unlike the spring flush which is preformed in the dormant bud, later flushes are neoformed, that is, nodes are initiated and extended during the same season. Neoformed growth depends on current season photosynthates and may compete with fruit growth for available resources. Neoformed growth is sensitive to water stress and trees on all three rootstocks grown under two levels of regulated deficit irrigation showed a reduction in both the number and length of neoformed shoots. Preformed shoot growth did not appear to be reduced under water stress conditions, supporting the hypothesis that preformed shoots are more dependent on environmental conditions during the season they are initiated than during the season they are extended. Additionally, preformed shoots on well irrigated trees were similar in length for all rootstocks, further supporting the idea that preformed shoots are under genetic control and are not easily manipulated.
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Kim, Park, Kang, Park, Yoo, Han, Cho, Kim, and Heo. "Green Tea Seed Oil Suppressed Aβ1–42-Induced Behavioral and Cognitive Deficit via the Aβ-Related Akt Pathway." International Journal of Molecular Sciences 20, no. 8 (April 15, 2019): 1865. http://dx.doi.org/10.3390/ijms20081865.
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The aim of this study was to investigate the availability of seeds, one of the byproducts of green tea, and evaluate the physiological activity of seed oil. The ameliorating effect of green tea seed oil (GTO) was evaluated on H2O2-induced PC12 cells and amyloid beta (Aβ)1–42-induced ICR mice. GTO showed improvement of cell viability and reduced reactive oxygen species (ROS) production in H2O2-induced PC12 cells by conducting the 2′,3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and 2′,7′-dichlorofluorescein diacetate (DCF-DA) analysis. Also, administration of GTO (50 and 100 mg/kg body weight) presented protective effects on behavioral and memory dysfunction by conducting Y-maze, passive avoidance, and Morris water maze tests in Aβ-induced ICR mice. GTO protected the antioxidant system by reducing malondialdehyde (MDA) levels, and by increasing superoxide dismutase (SOD) and reducing glutathione (GSH) contents. It significantly regulated the cholinergic system of acetylcholine (ACh) contents, acetylcholinesterase (AChE) activities, and AChE expression. Also, mitochondrial function was improved through the reduced production of ROS and damage of mitochondrial membrane potential (MMP) by regulating the Aβ-related c-Jun N-terminal kinase (JNK)/protein kinase B (Akt) and Akt/apoptosis pathways. This study suggested that GTO may have an ameliorating effect on cognitive dysfunction and neurotoxicity through various physiological activities.
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Fatiha, T., H. Abdelkrim, K. Mostefa, and R. Waffa. "Study of Morpho-Physiological and Biochemical Behavior of Cultivated Legume (Lens culinaris Medik Ssp culinaris) in Dry Area of Algeria." Ukrainian Journal of Ecology 9, no. 4 (December 7, 2019): 535–41. http://dx.doi.org/10.15421/2019_786.
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The victory over the protein deficiency afflicting millions of human beings is a crucial and urgent task for world agriculture. The legume Lentil (Lens culinaris Medik) is one of the largest sources of protein with an average of 25% of all seeds produced worldwide. When used in crop rotation, it fertilizes the soil, as is the case in North Africa and this plant holds an important place throughout the world. In Algeria, lentil is largely growth in the semi-arid zones of the interior plains characterized by various abiotic constraints such as terminal drought which causes significant losses in lentil yield every year. For this purpose, the cases in this study aims to evaluate the effect of end of cycle water stress on the behavior of four varieties of lentil (Syrie 229, Metropole, Balkan 75 and Ibela) and to elucidate the plant’s morpho-physiological and biochemical parameters involved in tolerance and to assess varieties which could be grown under water stress conditions. The experiment was conducted in a laboratory and greenhouse with a well-controlled condition. The experiment was arranged in a completely randomized design of two factors (water stress and varieties) with four replications and two treatments. Not treated plants (without water stress application) were utilized as control. The four tested genotypes were subjected to two water regimes, one irrigated throughout the cycle (No stressed) used as a control, the other one stressful from the beginning of flowering till seed’s filling stages (stressed). The study covered the variation of the relative water content in leaves as well as the leaf surface, the rate of proline and soluble sugars of the leaves and the total seed protein content. The obtained results showed that the studied genotypes behaved differently to the water stress. Thus, a significant decrease was observed in the relative water content from 75.29% to 70.71% and in the leaf area from 16.76 cm2 to 13.63 cm2. An opposite behavior was observed on the osmoticum accumulated as a response to water deficit. A significant increase in proline (150.14 μg/g DM to 203.69 μg/g DM) and in soluble sugars stress (60.42 μg/g DM to 110.21 μg/g DM) was detected in leaves under stressed conditions. The terminal water stress resulted also in an increase in protein content in lentil seeds from a mean value of 22.08% to 24.84%. Regarding the obtained results, Metropole genotype seems to be the most tolerant cultivar to water stress followed by Balkan 755.
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GOMES, F., and M. K. V. CARR. "EFFECTS OF WATER AVAILABILITY AND VINE HARVESTING FREQUENCY ON THE PRODUCTIVITY OF SWEET POTATO IN SOUTHERN MOZAMBIQUE. III. CROP YIELD/WATER-USE RESPONSE FUNCTIONS." Experimental Agriculture 39, no. 4 (September 29, 2003): 409–21. http://dx.doi.org/10.1017/s0014479703001406.
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In Mozambique the sweet potato (Ipomoea batatas) is grown as both a leafy vegetable, the terminal shoots or vines being progressively harvested during the season, and as a root crop. This paper reports the development of crop yield/water-use production functions using data from two irrigation experiments designed to evaluate the effects of water availability and vine harvesting practices on the productivity and water use (ETc) of sweet potato (cv. TIS 2534) during two contrasting seasons in the south of the country. As the frequency of vine harvesting increased, the water-use efficiency (WUE-ETc) for vine production (dry mass) increased from 1–2 to 4–5 kg ha−1 mm−1 during the rainy season, and from 1 to 9 kg ha−1 mm−1 during the dry season. By contrast, there was a corresponding reduction in the WUE-ETc for storage root production from 14 to 8–9 kg ha−1 mm−1 during the rainy season, and from 23 to 15–17 kg ha−1 mm−1 during the dry season. For the total yields (vines plus storage roots) the WUE-ETc during both seasons were independent of the vine harvesting treatment. Separate lines represented each season, the slopes of which were 13 kg ha−1 mm−1 in the rains, and 24 kg ha−1 mm−1 in the dry season. When, however, crop water-use was normalised using either the seasonal mean daily total of incoming solar radiation, or reference crop evapotranspiration (ETo), but not the saturation deficit of the air, a single common, linear relationship with yield resulted. Possible explanations for this are considered. Plotting relative yields against relative rates of water-use, also gave consistent results that could have general application for predicting the effects of water availability on productivity. Vine yields, when harvested frequently, were less sensitive to drought (yield response factor, Ky=0.7–0.9) than storage roots (Ky=1.2). For total production (vines plus roots), the sensitivity to water stress (Ky) increased, from 0.9–1.0 to 1.2, as the interval between vine harvests increased. Farmers in southern Mozambique trying to maximize total yield during the season, under conditions of water uncertainty, should harvest vines at intervals of not more than 14 days.
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Shimizu, Chikako, Yasuhiro Oki, Yutaka Mitani, Youichi Tsuchiya, and Toshitaka Nabeshima. "Moderate-dose Regular Lifelong Alcohol Intake Changes the Intestinal Flora, Protects against Aging, and Keeps Spatial Memory in the Senescence-accelerated Mouse Prone 8 (SAMP8) Model." Journal of Pharmacy & Pharmaceutical Sciences 19, no. 4 (November 3, 2016): 430. http://dx.doi.org/10.18433/j3990v.
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Purpose: Heavy and long-term alcohol consumption increase the risk of alcohol-related diseases. Epidemiological studies show moderate drinking reduces the risk of mortality, cardiovascular diseases, and brain infarction in the J-shaped or U-shaped curve effect. However, why moderate drinkers may be healthy and non-drinkers may be ill in diverse populations remains controversial. Herein, we examined the relationship between moderate/lifelong alcohol intake and aging, especially aging-related cognitive functions in senescence-accelerated mouse prone 8 (SAMP8) model. Methods: SAMP8 model (5-week-old, male, n = 36), a model of age-related cognitive deficit, were group-housed (n = 6/cage) and provided free access to water (water group, n = 18) or 1% ethanol (EtOH group, n = 18, intake started when mice were 9 weeks old). The object recognition test (ORT) and object location test (OLT) were used to evaluate cognitive functions. The intestinal flora at the age of 87 weeks was analyzed by terminal restriction fragment length polymorphism (T-RFLP). Results: The lifespan of the EtOH-group mice was about 4 weeks longer than that of the water-group mice. In the EtOH group, spatial recognition impairment, assessed by OLT, was observed later (age, 73 weeks) than that in the water group (age, 52 weeks). The spinal curvature and skin conditions progressed significantly slower in the EtOH group than in the water group. Moreover, diarrhea symptoms only appeared in the water group, at the age of 82 weeks. The T-RFLP analysis of the intestinal flora indicated higher Lactobacillales order and lower Clostridium cluster XI in the EtOH group than in the water group, although those were extremely high in some mice close to death in both groups. Water-group mice with diarrhea presented significantly higher Clostridium cluster XI than did those without diarrhea (P = 0.017). Conclusion: Moderate alcohol intake changes intestinal flora and positively affects aging of SAMP8 model.
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Sadok, Walid, and Rémy Schoppach. "Potential involvement of root auxins in drought tolerance by modulating nocturnal and daytime water use in wheat." Annals of Botany 124, no. 6 (March 28, 2019): 969–78. http://dx.doi.org/10.1093/aob/mcz023.
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Abstract Background and Aims The ability of wheat genotypes to save water by reducing their transpiration rate (TR) at times of the day with high vapour pressure deficit (VPD) has been linked to increasing yields in terminal drought environments. Further, recent evidence shows that reducing nocturnal transpiration (TRN) could amplify water saving. Previous research indicates that such traits involve a root-based hydraulic limitation, but the contribution of hormones, particularly auxin and abscisic acid (ABA), has not been explored to explain the shoot–root link. In this investigation, based on physiological, genetic and molecular evidence gathered on a mapping population, we hypothesized that root auxin accumulation regulates whole-plant water use during both times of the day. Methods Eight double-haploid lines were selected from a mapping population descending from two parents with contrasting water-saving strategies and root hydraulic properties. These spanned the entire range of slopes of TR responses to VPD and TRN encountered in the population. We examined daytime/night-time auxin and ABA contents in the roots and the leaves in relation to hydraulic traits that included whole-plant TR, plant hydraulic conductance (KPlant), slopes of TR responses to VPD and leaf-level anatomical traits. Key Results Root auxin levels were consistently genotype-dependent in this group irrespective of experiments and times of the day. Daytime root auxin concentrations were found to be strongly and negatively correlated with daytime TR, KPlant and the slope of TR response to VPD. Night-time root auxin levels significantly and negatively correlated with TRN. In addition, daytime and night-time leaf auxin and ABA concentrations did not correlate with any of the examined traits. Conclusions The above results indicate that accumulation of auxin in the root system reduces daytime and night-time water use and modulates plant hydraulic properties to enable the expression of water-saving traits that have been associated with enhanced yields under drought.
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Condon, AG, RA Richards, and GD Farquhar. "Relationships between carbon isotope discrimination, water use efficiency and transpiration efficiency for dryland wheat." Australian Journal of Agricultural Research 44, no. 8 (1993): 1693. http://dx.doi.org/10.1071/ar9931693.
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Carbon isotope discrimination (-) has been shown to be negatively correlated with water use efficiency for wheat cultivars grown in the glasshouse. In the field this negative correlation has been confirmed for peanut but it has yet to be confirmed for wheat. Indeed, several field studies on wheat have shown positive (rather than negative) relationships between dry matter production and -. The aim of this study was to determine the relationship between - and water use efficiency for wheat grown in a dryland environment characterized by winterlspring-dominant rainfall and terminal drought. Eight genotypes chosen to give a range in - of c. 2.0x10-3 were grown on a red earth at Moombooldool in the Riverina region of New South Wales. Water use and above-ground dry matter (DM) were measured over the course of the season. Water use was partitioned into transpiration and soil evaporation and values of crop water use efficiency (WET) and transpiration efficiency ( WT) calculated. To account for the effect on WT of seasonal changes in the vapour pressure deficit of the air (D), crop coefficients (k) were derived by multiplying WT by the transpiration-weighted average daytime value of D for each genotype. During the preanthesis period, when there was little limitation of soil water supply on growth, there was a positive relationship between DM and -, as observed previously. The relationship between WET and - also had a positive (though non-significant) trend, but the relationship between k and - was negative, i.e. once the effects of variation in the ratio T/ET and seasonal changes in D were accounted for, the negative correlation between water use efficiency and - re-emerged. This apparent conflict between WET and k arose because genotypes with high - values developed their leaf area faster, with two important consequences. First, high - genotypes transpired more of their water supply during the winter when D was low and the exchange of water for CO2 more efficient. Second, transpiration made up a greater proportion of total water use by high - genotypes. The relationship between water use efficiency and - was further complicated as the crops depleted the soil water store after anthesis. During this period DM production tended to be greater in low - genotypes that had conserved soil water in the preanthesis period. However, DM production also remained high for two high - genotypes. The cause of this variation in post-anthesis growth among high - genotypes was not established.
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Miranda, Ordilena Ferreira de, Saulo Eduardo Xavier Franco De Souza, Rodrigo José Milan, Aline Borges Bueno, and Marcilio de Almeida. "Influence of environment on the leaf morpho-anatomy and histochemical of the ayahuasca leaf: Populations cultivated in extra-Amazonian regions." Acta Scientiarum. Biological Sciences 42 (April 3, 2020): e50369. http://dx.doi.org/10.4025/actascibiolsci.v42i1.50369.
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Psychotria viridis Ruiz & Pav. (Rubiaceae) occurs naturally throughout the Amazon and it is traditionally used by indigenous communities, being incorporated into religious use in urban contexts over the last few decades. It is known and cultivated in many regions of South America for possessing valuable bioactive alkaloids. In this paper, we described P. viridis leaf morphology, anatomy and histochemistry from three populations cultivated in the southeastern Brazil, in order to identify possible adaptations to local environment and management. All plants presented terminal stipules and basic morpho-anatomical patterns of leaves, consistent with most species of the genus, as heterogeneous dorsiventral mesophyll, uniseriate epidermis, presents large cells with prominent vacuoles and druses. Unicellular non-glandular trichomes and multicellular starry trichomes were present in the primary and secondary veins. Amphi-hypostomatic leaf pattern, not yet described for the species, was common in all studied plants. Variation in the presence of domatia in the same population indicates that this structure cannot be used for taxonomic determination of P. viridis, as already described for other species of the genus. Presence of secretory ducts and reduction in stomata density and leaf area represent the main morpho-anatomic adaptations of plants from drier and warmer climates. Histochemical tests were positive for alkaloids, polysaccharides, proteins and phenolic compounds, being negative for starch only in plants subjected to water stress. We concluded that the morpho-anatomical and histochemical alterations found in the plants of this study resulted from seasonal water deficit adaptations and to maintain or attract mutualistic organisms.
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Mekliche, A., L. Hanifi Mekliche, A. Aidaoui, Ph Monneveux, and Amer Shneewer Hwazen. "Grain yield and its components study and their association with normalized difference vegetation index (NDVI) under terminal water deficit and well-irrigated conditions in wheat (Triticum durum Desf. and Triticum aestivum L.)." African Journal of Biotechnology 14, no. 26 (July 30, 2015): 2142–48. http://dx.doi.org/10.5897/ajb2015.14535.
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Kim, Jong Min, Uk Lee, Jin Yong Kang, Seon Kyeong Park, Eun Jin Shin, Hyun-Jin Kim, Chul-Woo Kim, Mahn-Jo Kim, and Ho Jin Heo. "Anti-Amnesic Effect of Walnut via the Regulation of BBB Function and Neuro-Inflammation in Aβ1-42-Induced Mice." Antioxidants 9, no. 10 (October 12, 2020): 976. http://dx.doi.org/10.3390/antiox9100976.
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This study was conducted to assess the protective effect of walnut (Juglans regia L.) extract on amyloid beta (Aβ)1-42-induced institute of cancer research (ICR) mice. By conducting a Y-maze, passive avoidance, and Morris water maze tests with amyloidogenic mice, it was found that walnut extract ameliorated behavioral dysfunction and memory deficit. The walnut extract showed a protective effect on the antioxidant system and cholinergic system by regulating malondialdehyde (MDA) levels, superoxide dismutase (SOD) contents, reduced glutathione (GSH) contents, acetylcholine (ACh) levels, acetylcholinesterase (AChE) activity, and protein expression of AChE and choline acetyltransferase (ChAT). Furthermore, the walnut extract suppressed Aβ-induced abnormality of mitochondrial function by ameliorating reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and ATP contents. Finally, the walnut extract regulated the expression of zonula occludens-1 (ZO-1) and occludin concerned with blood–brain barrier (BBB) function, expression of tumor necrosis factor-alpha (TNF-α), tumor necrosis factor receptor 1 (TNFR1), phosphorylated c-Jun N-terminal kinase (p-JNK), phosphorylated nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor (p-IκB), cyclooxygenase-2 (COX-2), and interleukin 1 beta (IL-1β), related to neuroinflammation and the expression of phosphorylated protein kinase B (p-Akt), caspase-3, hyperphosphorylation of tau (p-tau), and heme oxygenase-1 (HO-1), associated with the Aβ-related Akt pathway.
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Alahmad, Samir, Yichen Kang, Eric Dinglasan, Elisabetta Mazzucotelli, Kai P. Voss-Fels, Jason A. Able, Jack Christopher, Filippo M. Bassi, and Lee T. Hickey. "Adaptive Traits to Improve Durum Wheat Yield in Drought and Crown Rot Environments." International Journal of Molecular Sciences 21, no. 15 (July 24, 2020): 5260. http://dx.doi.org/10.3390/ijms21155260.
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Durum wheat (Triticum turgidum L. ssp. durum) production can experience significant yield losses due to crown rot (CR) disease. Losses are usually exacerbated when disease infection coincides with terminal drought. Durum wheat is very susceptible to CR, and resistant germplasm is not currently available in elite breeding pools. We hypothesize that deploying physiological traits for drought adaptation, such as optimal root system architecture to reduce water stress, might minimize losses due to CR infection. This study evaluated a subset of lines from a nested association mapping population for stay-green traits, CR incidence and yield in field experiments as well as root traits under controlled conditions. Weekly measurements of normalized difference vegetative index (NDVI) in the field were used to model canopy senescence and to determine stay-green traits for each genotype. Genome-wide association studies using DArTseq molecular markers identified quantitative trait loci (QTLs) on chromosome 6B (qCR-6B) associated with CR tolerance and stay-green. We explored the value of qCR-6B and a major QTL for root angle QTL qSRA-6A using yield datasets from six rainfed environments, including two environments with high CR disease pressure. In the absence of CR, the favorable allele for qSRA-6A provided an average yield advantage of 0.57 t·ha−1, whereas in the presence of CR, the combination of favorable alleles for both qSRA-6A and qCR-6B resulted in a yield advantage of 0.90 t·ha−1. Results of this study highlight the value of combining above- and belowground physiological traits to enhance yield potential. We anticipate that these insights will assist breeders to design improved durum varieties that mitigate production losses due to water deficit and CR.
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James, A. T., R. J. Lawn, and M. Cooper. "Genotypic variation for drought stress response traits in soybean. I. Variation in soybean and wild Glycine spp. for epidermal conductance, osmotic potential, and relative water content." Australian Journal of Agricultural Research 59, no. 7 (2008): 656. http://dx.doi.org/10.1071/ar07159.
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Studies were undertaken to assess genotypic variation in soybean and related wild species for traits with putative effects on leaf turgor maintenance in droughted plants. Traits of interest were (i) epidermal conductance (ge) which influences the rate of water loss from stressed leaves after stomatal closure; (ii) osmotic adjustment (OA) as indicated by tissue osmotic potential (π), which potentially affects the capacity to withdraw water at low soil water potential; and (iii) relative water content (RWC) at incipient leaf death (critical relative water content, RWCC), which is a measure of the dehydration tolerance of leaf tissue. The germplasm comprised a diverse set of 58 soybean genotypes, 2 genotypes of the annual wild species G. soja and 9 genotypes representing 6 perennial wild Glycine spp. indigenous/endemic to Australia. Seedling plants were grown in soil-filled beds in the glasshouse and exposed to terminal water deficit stress from the second trifoliolate leaflet stage (21 days after sowing). Measurements were made on well watered plants, moderately stressed plants, and at incipient plant death, in 2 separate studies. In both studies, there were significant genotypic differences in all 3 traits in the stressed plants. However, across the 3 sample times, ge decreased and the absolute magnitude of π increased, indicating that the expression of these traits changed as the plants acclimated to the stress. RWC was therefore used as a covariate to adjust the genotypic values of π and ge in order to facilitate comparison at a consistent plant water status of 70% RWC. There was statistically significant genotypic variation for the adjusted values, ge70 and π70, in both studies, and genotypic correlations between the 2 studies were significant (P < 0.05) and positive for all 3 traits: ge70 (r = 0.48), π70 (r = 0.50), and RWCC (r = 0.53). Among the soybean genotypes, there was at least a 2-fold range in ge70, a 0.7 MPa range in π70, and a 12 percentage point range in RWCC. Some of the perennial wild genotypes exhibited lower values of ge and RWCC and greater OA than soybean and G. soja, consistent with adaptation to drier environments. While the repeatability of measurement between experiments was variable among genotypes, the studies confirmed the existence of genotypic differences for ge, OA, and RWCC in cultivated soybean, with a wider range among the wild germplasm.
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James, A. T., R. J. Lawn, and M. Cooper. "Genotypic variation for drought stress response traits in soybean. III. Broad-sense heritability of epidermal conductance, osmotic potential, and relative water content." Australian Journal of Agricultural Research 59, no. 7 (2008): 679. http://dx.doi.org/10.1071/ar07161.
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The broad-sense heritability of 3 traits related to leaf survival in severely stressed plants was studied in several hybrid soybean populations. The 3 traits were epidermal conductance (ge), osmotic potential (π), and relative water content (RWC). The populations were generated by hybridising unrelated parental genotypes previously shown to differ in the 3 traits. ge (mm/s) was measured on well watered plants from 10 populations involving all combinations of 5 parental lines, grown in soil-filled beds in the glasshouse. π (MPa) and RWC (%) were measured on severely stressed plants of 3 populations involving all combinations of 3 different parents, growing into a terminal water deficit under a rainout shelter in the field. Broad-sense heritability for ge was significantly different from zero (P < 0.05) in all 10 populations and ranged from 60% to 93%. Heritability estimates for π70 (the tissue osmotic potential at 70% RWC) ranged from 33% to 71%. Only two estimates were statistically significant (P < 0.05) because of large standard errors and the fact that parental differences were smaller than previously observed. Broad-sense heritability for RWC of severely stressed plants ranged from 40% to 74%, and was statistically significant (P < 0.05) for 2 of the 3 populations. For all 3 traits, F2 progeny distributions were consistent with quantitative inheritance with a high degree of additive gene action. It was concluded that capacity exists to breed varieties with low ge, low π70, and high RWC in stressed plants. However, in the case of osmotic potential, genotypes with lower π70 combined with greater precision of measurement would be needed than proved possible in these studies. Further, specific strategies would be needed to select for the critical RWC, the minimal RWC at which leaf tissues die and which provides a measure of tissue dehydration tolerance. More research is also needed to characterise the dynamic relations between ge, π, and RWC in influencing leaf survival in soybean, before they could be confidently used in a breeding program to improve drought tolerance.
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Metzger, Jutta, Manuela Nied, Ulrich Corsmeier, Jörg Kleffmann, and Christoph Kottmeier. "Dead Sea evaporation by eddy covariance measurements vs. aerodynamic, energy budget, Priestley–Taylor, and Penman estimates." Hydrology and Earth System Sciences 22, no. 2 (February 9, 2018): 1135–55. http://dx.doi.org/10.5194/hess-22-1135-2018.
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Abstract. The Dead Sea is a terminal lake, located in an arid environment. Evaporation is the key component of the Dead Sea water budget and accounts for the main loss of water. So far, lake evaporation has been determined by indirect methods only and not measured directly. Consequently, the governing factors of evaporation are unknown. For the first time, long-term eddy covariance measurements were performed at the western Dead Sea shore for a period of 1 year by implementing a new concept for onshore lake evaporation measurements. To account for lake evaporation during offshore wind conditions, a robust and reliable multiple regression model was developed using the identified governing factors wind velocity and water vapour pressure deficit. An overall regression coefficient of 0.8 is achieved. The measurements show that the diurnal evaporation cycle is governed by three local wind systems: a lake breeze during daytime, strong downslope winds in the evening, and strong northerly along-valley flows during the night. After sunset, the strong winds cause half-hourly evaporation rates which are up to 100 % higher than during daytime. The median daily evaporation is 4.3 mm d−1 in July and 1.1 mm d−1 in December. The annual evaporation of the water surface at the measurement location was 994±88 mm a−1 from March 2014 until March 2015. Furthermore, the performance of indirect evaporation approaches was tested and compared to the measurements. The aerodynamic approach is applicable for sub-daily and multi-day calculations and attains correlation coefficients between 0.85 and 0.99. For the application of the Bowen ratio energy budget method and the Priestley–Taylor method, measurements of the heat storage term are inevitable on timescales up to 1 month. Otherwise strong seasonal biases occur. The Penman equation was adapted to calculate realistic evaporation, by using an empirically gained linear function for the heat storage term, achieving correlation coefficients between 0.92 and 0.97. In summary, this study introduces a new approach to measure lake evaporation with a station located at the shoreline, which is also transferable to other lakes. It provides the first directly measured Dead Sea evaporation rates as well as applicable methods for evaporation calculation. The first one enables us to further close the Dead Sea water budget, and the latter one enables us to facilitate water management in the region.