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1
Wilson, Brayton F. "Shoot-length frequencies in black birch (Betula lenta)". Canadian Journal of Forest Research 21, n. 10 (1 ottobre 1991): 1475–80. http://dx.doi.org/10.1139/x91-207.
Testo completoAbstract (sommario):
Lengths of all parent and current shoots were measured on three 8- to 10-year-old black birch (Betulalenta L.) trees with branches <8 years old. Older branches had more short shoots (<1 cm long) and shorter long shoots (>2 cm long) than younger branches. Parent long shoots produced three to nine basal short shoots. Observations on short-shoot production were consistent with the hypothesis that only buds with adequate nutrition formed long shoots. Three growth rules were developed for a model that simulated individual branch growth: (i) a regression predicting lateral shoot number from each parent shoot length; (ii) probabilities for the number of short shoots produced by a parent shoot based on the total number of current shoots produced per parent shoot; (iii) a regression predicting current shoot length from parent shoot length, current shoot position (longest to shortest), branch age, and main-axis elongation in the current and previous year. Simulations of 81 branches using these rules predicted shoot numbers and total shoot lengths close to those of the actual branches (R2 = 0.73–0.84).
2
Yagi, Takanobu. "Relationships between shoot size and branching patterns in 10 broad-leaved tall tree species in a Japanese cool-temperate forest". Canadian Journal of Botany 84, n. 12 (dicembre 2006): 1894–907. http://dx.doi.org/10.1139/b06-138.
Testo completoAbstract (sommario):
Within-tree variations in branching patterns (the patterns of daughter shoot production by mother shoots) are the basis of tree architectural plasticity and, therefore, were studied in 10 cool-temperate broad-leaved tall tree species including three species with distinct short shoots. The relationships between mother shoot length versus branching patterns (i.e., the number and size of daughter shoots) were quantified for each species using regression equations. The number and stem length of daughter shoots were greater on longer mother shoots, although the majority of daughter shoots were short on mother shoots of any size. The magnitude of lateral spread of the mother shoot – daughter shoot system relative to that of its main axis extension increased with increasing mother shoot length, indicating weaker apical control on longer mother shoots. Among species, the lower limit of daughter shoot length was shorter and the frequency of short daughter shoots was greater on mother shoots of species with more distinct short shoots. This indicates that species with distinct short shoots effectively avoid branch overcrowding by minimizing daughter shoot extension. Differences in branching patterns among mother shoots of different sizes are discussed in relation to their functional importance for tree architectural development.
3
Lauri, Pierre-Éric, e Jean-Jacques Kelner. "Shoot type demography and dry matter partitioning: a morphometric approach in apple (Malus ×domestica)". Canadian Journal of Botany 79, n. 11 (1 novembre 2001): 1270–73. http://dx.doi.org/10.1139/b01-113.
Testo completoAbstract (sommario):
In a study of the apple (Malus ×domestica Borkh.) canopy structure, 5-year-old 'Fuji' and 'Braeburn' trees grafted on a low-vigour rootstock (M9) were compared at both fruiting branch and shoot levels. Percentages of short ([Formula: see text]5 cm) shoots and short shoot leaf area were significantly higher on 'Braeburn' than on 'Fuji', (76.8% vs. 72.6% and 46.9% vs. 42.9% for 'Braeburn' and 'Fuji', respectively). This high percentage of short shoots as compared with literature data was probably due to the training method, which reduced vigour. At shoot level, the ratio between dry masses of axis and leaf, called the axialization index, was determined to compare short and long shoots. Axialization values were higher for 'Braeburn' than for 'Fuji'. Although overall and individual leaf area was greater on long shoots, long shoot axialization (0.64 and 0.54 for 'Braeburn' and 'Fuji', respectively) was approximately twice that of short shoots (0.36 and 0.24, respectively). Therefore, for short shoots, the reduced carbon investment in supporting tissues may explain the significant role short shoots played in supporting early fruit development. For long shoots, the longer time required to reach the autotrophic and then exporting stage as well as the detrimental effect of early extension shoot development on fruit set might be explained by greater axialization.Key words: long shoot, short shoot, axialization index, apple, Malus ×domestica, biomass partitioning.
4
Ishihara, Masae, e Kihachiro Kikuzawa. "Species-specific variation in shoot production patterns of five birch species with respect to vegetative and reproductive shoots". Canadian Journal of Botany 82, n. 9 (1 settembre 2004): 1393–401. http://dx.doi.org/10.1139/b04-099.
Testo completoAbstract (sommario):
We tested whether the difference in shoot production patterns of reproductive and vegetative shoots is only due to resource or meristem availability or also due to species-specific factors. Rates of shoot production by four shoot types (reproductive long shoots, vegetative long shoots, reproductive short shoots, and vegetative short shoots) in Betula platyphylla Sukatchev var. japonica (Miq.) Hara, Betula davurica Pall., Betula ermanii Cham., Betula grossa Sieb. et Zucc., and Betula maximowicziana Regel were compared. In the first three species, each shoot type produced all four shoot types. However, in the latter species, limited shoot production pathways were found both in reproductive shoots and in vegetative shoots, which do not carry any costs associated with reproduction. Furthermore, shoot production by reproductive shoots was not always diminished, but rather was enhanced compared with that by vegetative shoots in B. maximowicziana. These results suggest the importance of species-specific patterns in shoot production, in addition to previously suggested explanations involving resource or meristem limitation.Key words: species specificity, cost of reproduction, Betula, reproductive shoots, vegetative shoots.
5
Souza, João Paulo, Carlos Henrique B. A. Prado, Ana Lúcia S. Albino e Maria A. Damascos. "Shoot-foliage relationships in deciduous, semideciduous, and evergreen cerrado tree species". Brazilian Journal of Plant Physiology 21, n. 1 (2009): 76–86. http://dx.doi.org/10.1590/s1677-04202009000100009.
Testo completoAbstract (sommario):
The morphology and the biomass allocation in shoots and leaves were investigated in 15 cerrado tree species with distinct leaf phenology growing under natural conditions. Higher values of leaf/shoot ratio on mass base, individual leaf area, leaf area per shoot, leaf display index, and leaf number per shoot length were found in deciduous than in evergreen species. The differences about shoot-foliage relationship across leaf phenological groups could be explained by plagiotropic shoots on deciduous and by erect shoots in semideciduous and evergreen species. Plagiotropic shoots allow similar irradiance along shoots and high biomass allocation in favor of leaves without foliage self-shading in deciduous tree species. The structural differentiation between short and long shoots was indicated by an exponential relationship between leaf display index and shoot length in all deciduous, in three semideciduous, and in two evergreen species. Therefore, especially in deciduous, the short shoots had higher leaf area per unit of length than the long shoots. The differentiation between short and long shoots depends on the shoot length in deciduous because of the leaf number on shoot is predetermined in buds. Contrastingly, the leaf neo-formation in semideciduous and in evergreen tree species keeps the shoot-leaf relationship per shoot length more constant, because of the foliage being produced according to the shoot growth during the year. In conclusion, the foliage persistence, the shoot inclination, the type of leaf production and the resources allocation between autotrophic and heterotrophic vegetative canopy parts are interdependent in cerrado tree species across different leaf phenological groups.
6
Remphrey, W. R., e G. R. Powell. "Crown architecture of Larix laricina saplings: an analysis of higher order branching". Canadian Journal of Botany 65, n. 2 (1 febbraio 1987): 268–79. http://dx.doi.org/10.1139/b87-038.
Testo completoAbstract (sommario):
Quantitative analysis and simulation modelling of Larix laricina (Du Roi) K. Koch branches revealed a complex system of architectural patterns and correlations. Numbers of lateral buds and long shoots were positively correlated with parent-shoot length, but the relationships varied among shoot orders and for sylleptic shoots. For order 2 and sylleptic shoots, numbers of lateral long shoots were also correlated with associated terminal-shoot lengths. Sylleptic shoots produced more lateral long shoots than equivalent proleptic shoots. Lateral long-shoot lengths decreased basipetally and were correlated with terminal-shoot lengths. Lengths of order 2 lateral long shoots also varied independently with crown position. Generally, the degree of apical control decreased and the proportion of short shoots increased with positions of less vigour in the crown. Terminal long-shoot lengths varied with parent-shoot length, location, and to some extent parent-axis leader length. Terminal short-shoot production was associated with shorter parent shoots. Shorter order 2 shoots (<60 mm) and most order 3 shoots produced no lateral long shoots. The net result was that branch structural development ceased in less vigorous crown positions. The spatial disposition of shoots, as defined by elevation and divergence angles, varied with position of origin around and along parent shoots. Although variable, elevation angles decreased and divergence angles increased basipetally.
7
Johnson, R. S., e A. N. Lakso. "Carbon Balance Model of a Growing Apple Shoot: I. Development of the Model". Journal of the American Society for Horticultural Science 111, n. 2 (marzo 1986): 160–64. http://dx.doi.org/10.21273/jashs.111.2.160.
Testo completoAbstract (sommario):
Abstract A computer model simulating the C balance of a growing ‘Jonamac’ apple (Malus domestica Borkh.) shoot was constructed to estimate the time of first net carbohydrate export from the shoot. The model was based on measurements of net photosynthesis and dark respiration rates and estimates of the dry weight in the different components of the shoot. Under the prevailing weather of 1981, the model indicates that a shoot growing to a final length of 50 cm became a net exporter of carbohydrates 19 days after budbreak, a time corresponding to a shoot 4 cm long with 10 unfolded leaves. Assuming the same early growth rates, a shoot with a final length of 2 cm starts exporting at 15 days after budbreak. The total export of carbohydrates remains higher from short shoots than long shoots until 36 days after budbreak, indicating that short shoots supply greater amounts of carbohydrates to the rest of the plant during this early period. The model estimates the total import of carbohydrates from reserves of about 165 mg for the long shoot and 80 mg for the short shoot. In each instance, these reserves only accounted for about 20% of the total carbohydrates used by the shoot up to that point. The remainder was supplied by current photosynthates.
8
Saouab, Fatima-Ezzahra, e Mohammed Bendriss Amraoui. "Short Shoot Growth and Reproduction Response to Light Conditions Vary with Order Branching in the Proximal Part of C. atlantica Crown". International Journal of Forestry Research 2020 (10 febbraio 2020): 1–9. http://dx.doi.org/10.1155/2020/8383010.
Testo completoAbstract (sommario):
This study compared the effects of shading in individual branch orders 2 and 3 on the needle survival, growth, and reproduction of five categories of short shoots of the proximal part of wild Atlas cedar (Cedrus atlantica (Endl.) G. Manetti ex Carrière). The sun exposure did not affect the number of short shoots in the two branch orders, whereas light compared to shade only stimulates the unbranched short shoot elongation of the branch order 3. The impact of shade exposure compared to sun on the loss of needles depends on the order of branching; it is weak to order 2 and increases to higher order. This effect in the branch order 3 is achieved by a significant decrease of the fallen leaf number in the unbranched short shoot SSnr and the short shoot SS/T worn by Twigs while in the branch order 2 only short shoot SS (nr + r) loses significantly few needles. In terms of short shoot extension and needle loss, the SS/T of the branch order 3 behaves in the same way as the SS (nr + r) of the branch order 2. The shadow compared to sunlit only decreases significantly the production of pollen strobili of the branch order 2. Close relationships between short shoot extension, leaf life span, and pollen strobili production of axillary products in the proximal part of C. atlantica crown were found.
9
Remphrey, W. R., e G. R. Powell. "Crown architecture of Larix laricina saplings: production and disposition of foliage and their simulation". Canadian Journal of Botany 66, n. 11 (1 novembre 1988): 2234–46. http://dx.doi.org/10.1139/b88-306.
Testo completoAbstract (sommario):
In saplings of Larix laricina (Du Roi) K. Koch (tamarack), correlations between projected leaf area (PLA) and architectural variables such as shoot length and shoot age were incorporated into existing simulation models to estimate the distribution of PLA in the crown according to several spatial, temporal, and morphological parameters. After five generations of simulated shoot growth, PLA values ranged from 8.2 m2 for trees with short height growth increments (HGIs) and no syllepsis to 25.5 m2 for those with long HGIs and heavy syllepsis. Although PLA increased, the rate of increase declined over time. In early simulated generations, long-shoot PLA predominated. In the fifth simulated generation, short shoots bore about 75% of the PLA. There was a basipetal increase in PLA by HGI, but the relationship was nonlinear. In trees with syllepsis, sylleptic origin branches on individual HGIs carried more PLA than concomitant proleptic branches for 1 year but thereafter the proportions were reversed. Over successive generations, the contribution of different branch orders to the total PLA shifted from mostly first-order long shoots (including PLA on daughter short-shoot axes) to second-order shoots carrying more than 50% by year 5. Because of the short-shoot contribution, there was considerable PLA in all regions of the crown, although the greatest concentration was in lower regions of midconic zones. Simulated PLA index increased substantially with crown development. Trees with short HGIs had the greatest PLA index and those with long HGIs had the least.
10
Ruan, Yiqin, e Mark H. Brand. "In Vitro Responses of Tissues from Rhododendron Plants With and Without Tissue Proliferation". HortScience 30, n. 4 (luglio 1995): 873D—873. http://dx.doi.org/10.21273/hortsci.30.4.873d.
Testo completoAbstract (sommario):
Rhododendron `Montego' shoot cultures initiated from plants with and without tissue proliferation (TP and NTP) served as explant sources for all studies (Note: in vitro TP shoot cultures produce primarily dwarf shoots, some long shoots, and stem tumors). Calli induced from TP leaves and tumors and NTP leaves were cultured on woody plant (WP) medium containing NAA and 2-iP. During the first 4 weeks of culture, calli from NTP leaves had higher relative growth rates than calli from TP leaves or tumors. However, calli from TP leaves and tumors grew faster than calli from NTP leaves for all subculture periods that followed. Shoot tips (5 mm) were excised from TP dwarf shoots, TP long shoots, and NTP shoots and were cultured on WP medium with or without 15 μM 2-iP. Shoot tips from TP dwarf and long shoots multiplied on medium without 2-iP, averaging 18.4 and 1.7 shoots per shoot tip in 12 weeks, respectively. Shoot tips from NTP shoots only multiplied when maintained on 2-iP-containing medium. When placed on 2-iP-containing medium, both types of TP shoot tips produced clusters of callus-like nodules that gave rise to highly tumorized, short shoots or leafy meristems.
11
Bilbrough, C. J., e J. H. Richards. "Branch architecture of sagebrush and bitterbrush: use of a branch complex to describe and compare patterns of growth". Canadian Journal of Botany 69, n. 6 (1 giugno 1991): 1288–95. http://dx.doi.org/10.1139/b91-167.
Testo completoAbstract (sommario):
The concept of the modularity of plant growth form was incorporated with the fates of buds and used as a framework to describe the typical branch-level developmental morphology of sagebrush (Artemisia tridentata ssp. vaseyana (Rydb.) Beetle) and bitterbrush (Purshia tridentata (Pursh) D.C.). Typical branches included one 2-year-old long shoot and all 1-year-old long shoots originating from that twig. Growth patterns were examined by position along each long shoot within the experimental branches. Shoot fates were recorded for each node and biomass production was estimated. Both species had specific locations where vegetative long shoot production was higher than any other location within the experimental branches. Sagebrush had an overall linear (excurrent) growth form, with the leader long shoot much larger than lateral long shoots. Sagebrush produced many lateral long shoots and few short shoots. In contrast, bitterbrush had a branched (decurrent) growth form, with few long shoots and many short shoots. The leader rarely grew and was no larger than laterals. Knowledge of the location, frequency, and size of vegetative long shoot production within a branch complex provides an understanding of the repeated structure of plants. The branch-level approach provides the information necessary before the effects of environmental factors on growth patterns can be determined. Key words: Artemisia tridentata ssp. vaseyana (Rybd.) Beetle, branch architecture, bud fates, developmental morphology, Purshia tridentata (Pursh) D.C., shrub.
12
Nopiana, Rina, Hariadi Hariadi, Lalu Aji Kurniawan e Suryansah Suryansah. "Efektivitas jump shoot tanpa awalan dan jump shoot dengan awalan terhadap hasil tembak jump shoot". Jurnal Porkes 7, n. 1 (30 giugno 2024): 288–302. http://dx.doi.org/10.29408/porkes.v7i1.25895.
Testo completoAbstract (sommario):
This study aims to examine the effectiveness of jump shoot without a prefix and jump shoot with a prefix on the results of jump shoot shooting on basketball teams. This research is an experimental research with randomized pre and test control group design. The population of this study was the basketball team of SMAN 2 Selong 20 people. Sample aggota basketball extracurricular team members SMAN 2 Selong. The sampling technique used saturated sampling technique. Date collection techniques using tests. Date analysis techniques using t test before and after. The results of the date pretets jump shoot without a prefix obtained t count 28.401 and t table 2.093 while the posttest obtained t count 30.431 and t table 2.093. The significant value is 0.00 < 0.05, so Ho is rejected Ha is accepted. The pretest jump shoot data results with a prefix obtained t count 23.292 and t table 2.093 while the posttest obtained t count 36.622 and t table 2.093, with a significant value of 0.00 < 0.05, Ho is rejected and Ha is accepted. It is concluded that both treatment groups have the effect of training in increasing the shooting accuracy of jump shoot training with a prefix to increase the accuracy of jump shoot shots, accepted. Hypothesis two jump shoot training without a prefix increases the accuracy of jump shoot shots is also answered, accepted.
13
Sedlák, J., e F. Paprštein. "Micropropagation of cranberry (Vaccinium macrocarpon) through shoot tip cultures: Short communication". Horticultural Science 38, No. 4 (15 novembre 2011): 159–62. http://dx.doi.org/10.17221/115/2010-hortsci.
Testo completoAbstract (sommario):
The goal of this study was to determine an efficient micropropagation system for cranberry (Vaccinium macrocarpon Ait.). Cranberry cultivar Howes was successfully established in vitro using mercuric chloride in a concentration of 0.15% as a sterilization solution. Anderson’s rhododendron medium (AN), half-strength Murashige and Skoog medium (half-MS) and McCown woody plant medium (WPM) containing the cytokinin zeatin in concentrations 0.5, 1 or 2 mg/l were tested. Generally, the highest multiplication rate (2.7) was obtained for cv. Howes on AN medium with the concentration 1 mg/l of zeatin. The effects of indole-3-butyric acid (IBA), indole-3-acetic acid (IAA) and naphtalen acetic acid (NAA) on root induction were tested in WPM medium. The percentage of rooting was 100% for NAA, 86% for IBA and 81% for IAA. From the tested variants, auxin NAA also promoted the highest development of good quality roots (more than 5) per shoot without callus formation.
14
Kozlov, Mikhail V. "Contrasting response of mountain birch to damage by Eriocrania leafminers in polluted and unpolluted habitats". Canadian Journal of Botany 83, n. 1 (1 gennaio 2005): 73–79. http://dx.doi.org/10.1139/b04-158.
Testo completoAbstract (sommario):
The leafmining larvae of Eriocrania spp. (Lepidoptera, Eriocraniidae) develop in the expanding leaves of mountain birch, Betula pubescens subsp. czerepanovii (Orlova) Hämet-Ahti. The larva usually consumes over a half of the leaf, implying moderate foliar damage to an individual shoot. I demonstrated that in unpolluted forests, effects of damage are restricted to the mined leaf, which grows smaller and demonstrates higher fluctuating asymmetry than intact leaves. In contrast, in heavily polluted industrial barrens, mining of the single leaf adversely affects the entire shoot; timing and expression of responses depend on shoot type. In infested short shoots, intact leaves grow smaller and more asymmetrical than leaves in control shoots, whereas infested long shoots demonstrated no current-year response; this difference suggests that long shoots are more competitive than short shoots and can acquire additional resources to compensate for herbivore damage. In contrast, in the next year after damage, no consequences of mining were detected in short shoots, whereas infested long shoots produced lower numbers of axillary long shoots than controls. The detected interactive effects of pollution and leaf damage most probably result from resource limitation in birches growing on low-nutritive toxic soils.Key words: Betula pubescens subsp. czerepanovii, foliar damage, fluctuating asymmetry, Kola peninsula, leaf size, shoot growth.
15
Buxton, Katrina N., Michael J. Clearwater, K. Giles-Hansen, E. W. Hewett e Ian B. Ferguson. "Comparison of xylem sap mineral concentrations between kiwifruit shoot types using spittlebugs for non-destructive sampling of sap". Functional Plant Biology 34, n. 11 (2007): 1029. http://dx.doi.org/10.1071/fp07091.
Testo completoAbstract (sommario):
Excreta of the meadow spittlebug [Philaenus spumarius L. (Homoptera: Cercopidae)] feeding on leaves and pedicels of kiwifruit [Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson var. deliciosa ‘Hayward’] were collected from insects from two different positions in the vine: from long, non-terminating axillary shoots producing fruit that are high in Ca2+ and low in K+ and from short-terminating axillary shoots producing fruit that are low in Ca2+ and high in K+. The Ca2+, Mg2+, K+ and P concentrations in the excreta were determined, and found to be similar to those in the xylem sap. Daily and seasonal changes in xylem sap composition were compared in excreta collected from the two different shoot types. On average, Ca2+ and Mg2+ concentrations were higher and K+ and P concentrations were lower in xylem sap collected from pedicels on long, non-terminating axillary shoots than in sap collected from pedicels on short-terminating shoots. Differences in the mineral concentration between these two shoot types may therefore be due to differences in the xylem sap mineral concentration reaching the fruit. There was no measurable gradient in xylem sap composition within the parent shoots that could explain the differences between sap composition of the two axillary shoot types. Long, non-terminating shoots had higher leaf area, were more exposed, had higher stomatal conductance and rates of transpiration, and more negative leaf water potentials than short-terminating shoots. The higher xylem sap Ca2+ and Mg2+ concentrations of long shoots were therefore associated with higher rates of water transport to the long shoots. Xylem sap concentration differences between these two shoots types may have been because of differential loading or unloading of minerals between shoot types, associated with differences in transpiration rate or shoot growth rates. The higher transpiration rate of long shoots may cause phloem immobile minerals such as Ca2+ to accumulate to higher levels at cation exchange sites in the shoot apoplast, resulting in increased xylem sap concentrations arriving at the fruit.
16
Puntieri, Javier G., María S. Souza, Daniel Barthélémy, Cecilia Brion, Martín Nuñez e Camilo Mazzini. "Preformation, neoformation, and shoot structure in Nothofagus dombeyi (Nothofagaceae)". Canadian Journal of Botany 78, n. 8 (1 agosto 2000): 1044–54. http://dx.doi.org/10.1139/b00-069.
Testo completoAbstract (sommario):
Buds in different positions along trunk, main branch, secondary branch, and short branch parent shoots of young Nothofagus dombeyi (Mirb.) Blume trees were dissected, and the number of organs of their rudimentary shoots was counted. Bud contents were compared with the number of organs of sibling shoots developed in positions equivalent to those of the dissected buds. Cataphyll number was relatively constant for all buds. The number of green leaf primordia differentiated in each bud depended both on the position of the bud on the parent shoot and on the size of the parent shoot. Sibling shoots derived distally from large parent shoots had more nodes than the rudimentary shoots of buds in a similar position. Proximal sibling shoots derived from large parent shoots and all sibling shoots derived from small parent shoots are entirely preformed. In N. dombeyi, the size gradient of the sibling shoots derived from a particular parent shoot relates mostly to variation in organ preformation, organ neoformation, and internode extension. The expression of each of these sources of variation is related to the position of the sibling shoot on the parent shoot and on the position of the parent shoot on the tree. Consideration is given to the role of environmental conditions on tree development, in view of the species' morphogenetic gradientsKey words: branching, bud content, sylleptic branching, leaf primordia, Nothofagus, preformation.
17
Ueno, Naoto, Hiroshi Kanno e Kenji Seiwa. "Sexual differences in shoot and leaf dynamics in the dioecious tree Salix sachalinensis". Canadian Journal of Botany 84, n. 12 (dicembre 2006): 1852–59. http://dx.doi.org/10.1139/b06-142.
Testo completoAbstract (sommario):
In the dioecious tree Salix sachalinensis Fr. Schm., females invested a greater amount of biomass to reproductive organs compared with males, indicating a greater reproductive cost in females. To elucidate mechanisms for the compensation of reproductive costs in females, we examined differences between the sexes in resource allocation, leaf and shoot dynamics, and leaf photosynthetic ability. In individual 1-year-old shoots, greater vegetative shoot biomass was observed in females than in males, although the mean mass of individual vegetative shoots was lower in females than in males. In both sexes, vegetative shoots at the proximal end of 1-year-old shoots completed their annual leaf production earliest and began shedding leaves earliest, although the light conditions did not differ from those at the terminal end. The leaf and shoot structure and dynamics in S. sachalinensis suggest effective carbon gain for both sexes by always placing new leaves with high photosynthetic rates at terminal shoot positions. In females, in particular, the net carbon gain would be increased by reducing construction and respiration costs and tissue loss by placing inexpensive small shoots in proximal shoot positions. To investigate to what extent the photosynthetic capacity of short-lived shoots compensated for reproductive costs in females, 80% of the vegetative-shoot buds were removed from 1-year-old shoots in females and males to simulate natural shoot shedding. In the current year, shoot removal did not reduce reproductive investment, but strongly reduced the diameter growth of 1-year-old shoots, in which the reduction was much greater in females than in males. In the following year, a reduction in reproductive investment was observed in females. Females of S. sachalinensis compensated for reproductive costs, not only by investing a greater amount of biomass in vegetative shoots, but also by using a more effective system of carbon acquisition (rapid leaf turnover on inexpensive shoots) than males.
18
Little, Stefan A., Brooke Jacobs, Steven J. McKechnie, Ranessa L. Cooper, Michael L. Christianson e Judith A. Jernstedt. "Branch architecture inGinkgo biloba: Wood anatomy and long shoot-short shoot interactions". American Journal of Botany 100, n. 10 (ottobre 2013): 1923–35. http://dx.doi.org/10.3732/ajb.1300123.
Testo completo
19
Wilson, Brayton F. "Compensatory shoot growth in young black birch and red maple trees". Canadian Journal of Forest Research 23, n. 2 (1 febbraio 1993): 302–6. http://dx.doi.org/10.1139/x93-040.
Testo completoAbstract (sommario):
Black birch (Betulalenta L.) and red maple (Acerrubrum L.) trees 1.5–2 m tall responded by compensatory (increased) shoot growth following a single treatment where shoots on the whole tree were clipped. Total shoot length of clipped trees recovered to control levels after 1 year's growth. The remaining buds on clipped shoots grew more than they would have without clipping. Frequency distributions of shoot lengths shifted toward longer lengths in clipped trees in the 1st year, but were similar to controls 2 years after clipping. The longest shoots were as long, or longer, on clipped shoots as on unclipped shoots. The major compensatory growth mechanism was increased growth of lateral buds. Clipping induced a few preventi-tious buds to form shoots and a few unclipped short shoots to grow as long shoots.
20
Struve, Daniel K. "Cultural Treatment and Cutting Type Affects Growth of ‘Heritage’ Birch Rooted Cuttings". Journal of Environmental Horticulture 3, n. 3 (1 settembre 1985): 142–46. http://dx.doi.org/10.24266/0738-2898-3.3.142.
Testo completoAbstract (sommario):
Rooted cuttings of Betula nigra ‘Heritage’ originating from short shoots were either staked and lateral shoots pruned to a 3 node length or were unstaked and unpruned. One hundred and twenty-five days following propagation, the pruned and staked plants had higher net assimilation rates and lower leaf area ratios than unstaked and unpruned plants. No differences in relative growth rates, total dry weight, root/shoot ratios or shoot length were observed between control and treated plants. Pruned and staked plants had, relative to unstaked and unpruned, less leaf surface area composed of fewer but larger leaves which produced more grams of dry weight per cm2 leaf surface area per day. Pruning and staking maximized economically important dry matter production without reducing total dry weight. Plants originating from long shoots had greater root, shoot and total dry weights, and required less staking to produce upright growth than plants originating from short shoots. By exploiting the beneficial topophysis growth of long shoots, nursery productivity can be increased.
21
Vujović, T., Dj Ružić e R. Cerović. "In vitro shoot multiplication as influenced by repeated subculturing of shoots of contemporary fruit rootstocks". Horticultural Science 39, No. 3 (15 agosto 2012): 101–7. http://dx.doi.org/10.17221/208/2011-hortsci.
Testo completoAbstract (sommario):
In vitro shoots of vegetative rootstocks for cherry (Gisela 5 and Gisela 6), plum (Fereley Jaspi) and pear (Pyrodwarf) were repeatedly subcultured for 10 subcultures on Murashige and Skoog medium of unchanged hormonal composition. Shoot formation capacity decreased over repeated subculturing in all genotypes. The first significant decrease in multiplication index was observed after first subculture in Gisela 6 and Fereley Jaspi, while in Gisela 5 the decline occurred after second subculture, and remained at that level. As for Gisela 6 and Fereley Jaspi, multiplication index was mainly stable from second to forth subculture, whereupon the second decline in shoot formation was observed. Although Pyrodwarf showed very low multiplication capacity, shoot multiplication slightly increased over the first three subcultures and then declined. This irreversible decline could be due to residual effects of hormones. However, no visible morphological variations or aberrations of shoots were found in successive subcultures in any genotype. Quality of shoots in terms of shoot length varied during subculturing, but the highest quality was observed in later subcultures (from fifth subculture onwards). After subculturing, several media were evaluated for induction of rhizogenesis in order to achieve high rooting rates in tested rootstocks. The highest rooting ability (100%) among genotypes was observed in Fereley Jaspi, followed by Pyrodwarf and Gisela 6 (the best rooting percentage being 90% in both) and Gisela 5 (70%). Rooted shoots were successfully acclimatized under the mist system in greenhouse.
22
Chée, R., e R. M. Pool. "Morphogenic Responses to Propagule Trimming, Spectral Irradiance, and Photoperiod of Grapevine Shoots Recultured in Vitro". Journal of the American Society for Horticultural Science 114, n. 2 (marzo 1989): 350–54. http://dx.doi.org/10.21273/jashs.114.2.350.
Testo completoAbstract (sommario):
Abstract In an effort to improve grapevine micropropagation, shoot proliferation and rooting in response to explant preparation and incubation conditions were investigated. The explants were three- to four-node shoots (15 mm) of the Vitis hybrid ‘Remaily Seedless’ cultured in vitro. The factors considered were white light of diverse spectral irradiance distributions, blue light, red light, 10-hr light/14-hr dark and 16-hr light/8-hr dark photoperiods, and leaf and/or apex removal from the explant. In white light and short days, leaf and/or apex removal did not affect shoot production; however, more shoots of at least three nodes, the desired size for micropropagation, were produced when leaves were retained. Shoot production was significantly greater in blue than in red light. Differences in shoot production in white lights of various spectral irradiance distributions were attributed to differences in blue : red irradiance ratios. Shoot production was greater with ratios of 0.6 to 0.9 than with lower and higher ratios. A greater percentage of subcultured shoots rooted in long days and red light than in blue or white light. The number of roots produced per shoot, and total root length, were also greater in red light.
23
Clarke, Austin. "Don't Shoot, Don't Shoot!" Callaloo 29, n. 2 (2006): 254–63. http://dx.doi.org/10.1353/cal.2006.0094.
Testo completo
24
Ab Rahman, Zuraida, Mohd Shukri Mat Ali, Mohd Norfaizal Ghazalli, Khadijah Awang e Ayu Nazreena Othman. "Optimization of Culture Media Formulations for Micropropagation of Lepisanthes fruticosa". Biosciences, Biotechnology Research Asia 15, n. 1 (24 marzo 2018): 51–58. http://dx.doi.org/10.13005/bbra/2607.
Testo completoAbstract (sommario):
Tissue culture provides an avenue for the production of high quality clonal plants in large numbers within a short time. Here, we describe the development of protocols for reproducible in vitro micropropagation of Lepisanthes fruticosa via direct organogenesis. Shoots were initiated from two types of explants, nodes and young shoots, to establish in vitro cultures on Murashige and Skoog’s (MS) medium or Woody Plant Medium (WPM) supplemented with different concentrations of benzylaminopurine (BAP). Semi-solid WPM media containing 1 mg/L BAP was most effective in shoot initiation in both node and young shoot explants, giving 40% and 20% shoot induction, respectively. The highest rate of shoot proliferation from young shoot explants was obtained using BAP at 3.0 mg/L in combination with NAA at 1.0 mg/L in WPM culture medium. This combination of growth regulators in the medium was also suited to root initiation.
25
Hayes, P. A., T. A. Steeves e B. R. Neal. "An architectural analysis of Shepherdia canadensis and Shepherdia argentea: patterns of shoot development". Canadian Journal of Botany 67, n. 6 (1 giugno 1989): 1870–77. http://dx.doi.org/10.1139/b89-237.
Testo completoAbstract (sommario):
In the context of an architectural analysis, the seasonal pattern of shoot development of Shepherdia canadensis and S. argentea (Elaeagnaceae) was examined. In both species floral bud burst was the first outward manifestation of seasonal activity. Vegetative shoots of S. canadensis expanded 3 – 5 pairs of preformed leaves during a period of 9 – 10 weeks. There was no pattern of internodal length that identified annual increments. In S. argentea, 6 – 18 pairs of leaves expanded during a period of 15 – 17 weeks, the variation being related to the extent of neoformation. There was a distinct pattern of internodal length, with a maximum in midseason, so that annual increments could be recognized subsequently. Lateral buds in S. canadensis expanded only proleptically as either short shoots or long shoots. Most had declining growth rates in the subsequent year and within 5 to 7 years had undergone abscission. In S. argentea. lateral buds expanded both sylleptically and proleptically as short shoots, long shoots, or thorns. The distribution pattern of these lateral types was related to the vigour of parent shoot growth. Some abscission of short shoots was noted. For each species a stochastic flow chart of shoot development was prepared and a computer program incorporating actual data was written that simulated shoot development for up to four generations of growth. Comparison of the two species indicates that S. argentea is more plastic in response to environmental conditions.
26
Chen, Wen-Shaw, Hsueh-Wen Chang, Wen-Huei Chen e Yih-Shyan Lin. "Gibberellic Acid and Cytokinin Affect Phalaenopsis Flower Morphology at High Temperature". HortScience 32, n. 6 (ottobre 1997): 1069–73. http://dx.doi.org/10.21273/hortsci.32.6.1069.
Testo completoAbstract (sommario):
Gibberellin A3 (GA3: 1, 3, or 5 (μg/shoot), 6N-benzyladenine (BA: 1, 3, or 5 μg/shoot), or both were applied to the flowering shoots of a white hybrid Phalaenopsis orchid (Leda) when they were 2 to 3 cm (stage 1, no flower primordial long at high temperature (30 °C day/25 °C night). When flowering shoots were treated with GA3, alone, deformed flowers were more frequent with increasing GA3 concentrations. The occurrence of GA3-induced deformed flowers was prevented by BA at the same dose as GA3 when applied 4 days after GA3 treatment. BA (1, 3, or 5 μg/shoot) was also applied 4 days before (time 1) or 4 days after (time 2) GA3 (1 (μg/shoot) treatment for regulating plant characteristics. The application of BA at 1 or 5 μg/shoot to stage 1 flowering shoots at time 2 resulted in short internodes between florets, whereas BA application at time 1 had no effect. Simultaneously, BA at 1 or 5 μg/shoot applied at time 1 or time 2 to stage 2 (5 to 6 cm long, two- to three-flower primordia) flowering shoots also shortened internode length between florets as compared to GA3 alone. When a stage 1 flowering shoot was given BA (3 or 5, but not 1 μg/shoot) and then treated with GA3 4 days later, flower count was slightly reduced as compared to treating with (GA3 alone. However, a high dose of BA applied at time 1 or time 2 on stage 2 flowering shoots had no effect on flower count. Chemical names used: N-(phenylmethyl)-lH-purine-6-amine [benzyladenine (BA)], gibberellic acid (GA3).
27
Malan, Daniel G., e Gerard Jacobs. "Effect of Photoperiod and Shoot Decapitation on Flowering of Leucospermum `Red Sunset'". Journal of the American Society for Horticultural Science 115, n. 1 (gennaio 1990): 131–35. http://dx.doi.org/10.21273/jashs.115.1.131.
Testo completoAbstract (sommario):
Incandescent light night break (NB) and day continuation (DC) prevented flower formation in Leucospermum R.Br. cv. Red Sunset. Natural short days (NSD) during winter were inductive for flowering of intact shoots until 28 Aug. (Southern Hemisphere), but only until 24 July for decapitated shoots. Vegetative axillary buds released from correlative inhibition by shoot decapitation were less responsive to inductive short days (SD) than distal axillary buds on intact shoots. At least 42 inductive SD cycles were required for normal flowering after cessation of shoot growth. The effective length of the NB depended on the length of the NSD of winter. A 2-hr NB prevented flowering in vegetative buds released from correlative inhibition by shoot decapitation on 3 Mar., but was inadequate for axillary buds on shoots decapitated on 1 May. When the NB was begun during winter and discontinued before natural day (ND) lengths became too long in spring, the flowering time was delayed.
28
Plessis, Helena Jacoba du, Roumiana Vassileva Nikolova, Bronwyn Anne Egan e Riana Kleynhans. "Preliminary study on in vitro shoot culture of Hibiscus coddii subsp. barnardii, an indigenous South African flowering plant". Ornamental Horticulture 27, n. 3 (settembre 2021): 408–16. http://dx.doi.org/10.1590/2447-536x.v27i3.2353.
Testo completoAbstract (sommario):
Abstract In vivo and in vitro grown plants of Hibiscus coddii subsp. barnardii were used as explant source for establishment of in vitro cultures. Nodal shoot explants derived from in vivo grown plants, both naturally and under controlled environmental conditions, showed high sensitivity to the surface disinfection treatment and poor survival in in vitro culture. In vitro grown seedlings proved successful as aseptic source of apical and basal shoot explants to establish contamination-free in vitro cultures. Sprouting of axillary buds was observed on 90% of apical shoot explants after four weeks of culture on full strength, plant growth regulator (PGR)-free Murashige and Skoog (MS) medium. However, further proliferation of short shoots, limited to the bud sprout at the explant base, occurred on only 50% of these explants. In contrast, all basal shoot explants attained 3-5 single primary axillary shoots (30-40 mm in length) while a clump of short (5-10 mm) shoots also formed at the base in 60% of these explants. In both explant types, addition of 0.25-1 mg L-1 6-Benzylaminopurine (BAP) to the MS medium resulted in a low frequency (10%-60%) of explants with short shoots (5-10 mm) that showed no further elongation. Moreover, explants cultured in the presence of BAP showed a high frequency of callus formation (up to 90%) and low survival (20%-60%). A lower frequency of callus formation (30%-40%) and higher survival (90%-100%) of both explant types occurred on BAP-free medium. Further subculturing of primary and secondary axillary shoots onto fresh MS medium (with and without BAP) did not improve shoot multiplication. Regenerated plantlets from PGR-free MS medium were successfully acclimatized and hardened-off.
29
Koppenaal, R. S., e S. J. Colombo. "Heat tolerance of actively growing, bud-initiated, and dormant black spruce seedlings". Canadian Journal of Forest Research 18, n. 9 (1 settembre 1988): 1103–5. http://dx.doi.org/10.1139/x88-169.
Testo completoAbstract (sommario):
To determine the effect of stage of bud development on heat tolerance, overwintered black spruce seedlings (Piceamariana (Mill.) B.S.P.) were (i) maintained in a dormant state, (ii) allowed to grow new shoots under favorable greenhouse conditions, or (iii) induced to initiate bud scales using short-photoperiod treatment following a period of new shoot elongation. Seedlings of the three shoot types were then exposed for 10 min to temperatures of 25, 42, 45, 50, or 55 °C in an environmental test chamber. Damage to the current-year shoot was lower in bud-initiated seedlings than in active seedlings, particularly at 42 °C, when 0 and 46%, respectively, of the length of the main shoot was damaged. The current-year shoot growth was much more sensitive to heat stress than the lignified first-year shoot, and therefore dormant seedlings, which had only first-year shoot growth, were most heat tolerant, showing damage only at 50 and 55 °C.
30
Kitaoka, Satoshi, Qu Laiye, Yoko Watanabe, Makoto Watanabe, Toshihiro Watanabe e Takayoshi Koike. "Heterophyllous Shoots of Japanese Larch Trees: The Seasonal and Yearly Variation in CO2 Assimilation Capacity of the Canopy Top with Changing Environment". Plants 9, n. 10 (28 settembre 2020): 1278. http://dx.doi.org/10.3390/plants9101278.
Testo completoAbstract (sommario):
Japanese larch (Larix kaempferi = L. leptolepis) is often characterized by its high growth rate with heterophyllous shoots, but the functional differences of heterophyllous shoots still remain unclear. Recently, abrupt high temperature and drought during spring induced high photosynthetic rate via change in leaf morphology of the deciduous habit. In order to reveal the photosynthetic characteristics of both short and long-shoot needles of sunny canopy of the larch trees using a canopy tower, we calculated the seasonal change of gas exchange characters and leaf mass per area (LMA) and foliar nitrogen content (N) of heterophyllous needles: short and long-shoot needles over 3 years. No marked difference in light-saturated photosynthetic rates (Psat) was observed between short and long shoots after leaf maturation to yellowing, although the difference was obvious in a specific year, which only shows that seasonal change in temperature and soil moisture determines the in situ photosynthetic capacity of needles. The large annual and seasonal variations in Psat in both shoots were found to be mainly determined by climatic variations, while shoot types determined the strategy of their photosynthetic N utilization as well as the stomatal regulation.
31
Darby, Ian D., Shahla Hosseini Bai, Helen M. Wallace e Stephen J. Trueman. "Micropropagation of the therapeutic-honey plants Leptospermum polygalifolium and L. scoparium (Myrtaceae)". Australian Journal of Botany 69, n. 5 (2021): 310. http://dx.doi.org/10.1071/bt21047.
Testo completoAbstract (sommario):
Demand for therapeutic honey is driving establishment of Leptospermum plantations. This study developed micropropagation methods for two species – Leptospermum polygalifolium Salisb. and L. scoparium J.R.Forst. & G.Forst. The study determined how shoot proliferation and adventitious rooting were influenced by the original explant position on the seedling and the concentration of benzyladenine (BA) in the proliferation medium. Hormone-free node culture was highly effective for both species. Nodal explants often formed roots in the absence of BA and developed elongated axillary shoots. Median shoot numbers of 584 and 659 were formed in 31–32 weeks from a single L. polygalifolium or L. scoparium seed, respectively. A low BA dose was effective for callogenesis and shoot proliferation of L. polygalifolium, but not L. scoparium. The median number of shoots produced from a single L. polygalifolium seed was 630 using 2.22-μM BA. This dose induced extremely high shoot numbers in some clones because explants often produced extensive callus and multiple short shoots. Shoots formed adventitious roots without indole-3-butyric acid and plantlets were acclimatised to nursery conditions. The original explant position did not influence shoot proliferation or adventitious rooting. Leptospermum polygalifolium and L. scoparium proved amenable to micropropagation, facilitating rapid establishment of nectar plantations.
32
Zając, Tadeusz, Halina Góral, Robert Witkowski e Ludwik Spiss. "Morphological traits and yield of red clover (Trifolium pratense L.) genotypes with varying inflorescence length". Acta Agrobotanica 55, n. 2 (2013): 89–100. http://dx.doi.org/10.5586/aa.2002.047.
Testo completoAbstract (sommario):
Two red clover breeding strains with elongated flower heads, developed by one of the authors (H.Góral), were studied for forage and seed yield and compared to the standard cultivar 'Nike'. In addition, six morphological shoot traits were measured and their interrelations were computed. The leaf area index (LAI) of successive cuts in two harvest years was determined on the basis of shoot density and leaf area of individual shoots. All three genotypes exhibited a high leaf area on shoots and a very high forage productivity. Among the morphological traits only shoot height could be a good selective criterion because it is easily measured, is significantly associated with shoot weight and shoot leaf area and its variation is low. Both strains, particularly the one with longer inflorescences belong to short-lived red clover forms giving satis factory forage and seed yields in the first harvest year. Depending on the strain the number of seeds per elongated inflorescence in the first harvest year was higher by 92 and 42% compared to that of a standard cultivar.
33
Arnott, J. T., S. C. Grossnickle, P. Puttonen, A. K. Mitchell e R. S. Folk. "Influence of nursery culture on growth, cold hardiness, and drought resistance of yellow cypress". Canadian Journal of Forest Research 23, n. 12 (1 dicembre 1993): 2537–47. http://dx.doi.org/10.1139/x93-314.
Testo completoAbstract (sommario):
The influence of short-day (9 h) and long-day photoperiods (18 h), and three levels of plant moisture stress (none and dried to predawn shoot water potentials of −1.0 or −1.8 MPa), applied for 7 weeks beginning in mid-July 1990, were studied on greenhouse-grown stecklings (rooted cuttings) of yellow cypress (Chamaecyparisnootkatensis (D. Don) Spach). A series of morphological and physiological measurements were made on the stecklings during and after the treatment period. Moisture stress significantly reduced steckling shoot growth and shoot dry weight by lowering net photosynthesis rates, while short-day photoperiods did not. The most pronounced growth reductions occurred when the treatments were combined, but effects were short-lived, with shoot growth resuming soon after the treatments ended. The short-day and moisture-stress treatment had no significant effect on root dry weight, shoot/root ratio, or water balance ratio. The risk of using moisture stress to control shoot growth in the nursery was low; mortality did not occur until the stecklings had been without water for at least 9 days. Moisture-stress treatments increased steckling root growth potential but had little effect on osmotic adjustment, cell elasticity, dry weight or symplastic fractions, cuticular transpiration, resistance to plant water movement, and relative water content of the shoots; short-day treatments had no influence on any of these parameters. Short days and moisture stress, singly or combined, had little effect on steckling cold hardiness. Steckling gas exchange rates were reduced significantly by low root temperature. In a 6-week controlled-environment simulation of planting-site moisture conditions, no significant differences in steckling net photosynthesis, transpiration, or stomatal conductance were found among nursery treatments; those that had been subjected to moisture stress in the nursery had small growth increases after planting in both wet and dry soil moisture regimes. We conclude that shoot growth of yellow cypress stecklings was controlled in the nursery using 9-h photoperiods and −1.8 MPa predawn shoot water potentials. Improved cold hardiness of the stecklings was not achieved using these nursery cultural methods, but moisture stress did confer some measure of drought resistance immediately after treatment, with higher root growth potential and lower shoot mass.
34
Gross, Paula M., e Stephen C. Myers. "067 SHOOT ORIENTATION AFFECTS PEACH SHOOT AND FRUIT GROWTH". HortScience 29, n. 5 (maggio 1994): 437e—437. http://dx.doi.org/10.21273/hortsci.29.5.437e.
Testo completoAbstract (sommario):
One-year old fruiting shoots averaging 50 cm in length were tagged according to naturally-occurring orientations ranging from vertical to horizontal throughout the canopies of dormant `Encore' peach (Prunus persica L Batsch) trees. Following fruit set, tagged shoots were thinned to two or three fruit per shoot. Fruit diameter, terminal shoot extension, and shoot orientation were measured at intervals throughout the season. Fruit were harvested at uniform maturity based on ground color for assessment of fresh weight, diameter, percent red blush, and red color intensity. A linear relationship (p=.001) was found between final fruit size and initial orientation, with fruit diameters 6 percent larger on shoots initially oriented horizontally than those initially vertical. Fruit size differences were not detected until the last two to three weeks of growth. Fruit size response to orientation was found to be independent of light. Red color development was not influenced, probably due to fairly uniform light environments within the canopies. Terminal shoot length was linearly related to initial orientation, with shoots initially oriented horizontally having the least terminal shoot extension. Development of lateral shoot growth in relation to shoot orientation will be discussed.
35
Konovalova, Irina, e Natalya Savinykh. "Biomorphs Solanum dulcamara L. and their contribution in seasonal climate grasses origin". BIO Web of Conferences 24 (2020): 00039. http://dx.doi.org/10.1051/bioconf/20202400039.
Testo completoAbstract (sommario):
The paper demonstrates S. dulcamara ecobiomorphs: a long rhizome semi-woody liana (LSL), a long rhizome subshrub with ascending shoots (LSAS), a root sucker subshrub and a shortlived plants of vegetative origin; and ontobiomorphs: a taproot upright subshrub (TUS), a subshrub with a mixed root system (SMRS), LSL, and LSAS. Possible stages and modes are suggested of Solanum biomorph transformation: 1. TUS, as a result of prolongation on the shoot (adventitious roots) and shoot system level (two or more replacement shoots), deviations on individual plant level (shoot lodging), transforms into SMRS; 2. SMRS, through the plant’s ontogenesis abbreviation (fragmentation), prolongation (epigeogenum rhizome), and deviation (stem twisting), transforms into LSL. Further LSL habit transformations can occur in xerophylous and hygrophylous biomorph evolution lines. On dry soil, as a result of prolongation (adventitious buds on roots), a root sucker subshrub appears. A hygrophyle line is possible in case of prolongations on the shoot level (metamere number increase within a shoot, dicyclic shoots), of the individual plant abbreviations (shortened life-time of sympodial axes, early fragmentation) and end with a short-lived plants of vegetative origin. Possibly, mien changes in S. dulcamara ontogenesis show possible stages in Solanum life forms transformation, from tree forms to LSL.
36
Neugebauer, Konrad, Martin R. Broadley, Hamed A. El-Serehy, Timothy S. George, Neil S. Graham, Jacqueline A. Thompson, Gladys Wright e Philip J. White. "Sodium hyperaccumulators in the Caryophyllales are characterized by both abnormally large shoot sodium concentrations and [Na]shoot/[Na]root quotients greater than unity". Annals of Botany 129, n. 1 (4 ottobre 2021): 65–78. http://dx.doi.org/10.1093/aob/mcab126.
Testo completoAbstract (sommario):
Abstract Background and Aims Some Caryophyllales species accumulate abnormally large shoot sodium (Na) concentrations in non-saline environments. It is not known whether this is a consequence of altered Na partitioning between roots and shoots. This paper tests the hypotheses (1) that Na concentrations in shoots ([Na]shoot) and in roots ([Na]root) are positively correlated among Caryophyllales, and (2) that shoot Na hyperaccumulation is correlated with [Na]shoot/[Na]root quotients. Methods Fifty two genotypes, representing 45 Caryophyllales species and 4 species from other angiosperm orders, were grown hydroponically in a non-saline, complete nutrient solution. Concentrations of Na in shoots and in roots were determined using inductively coupled plasma mass spectrometry (ICP-MS). Key Results Sodium concentrations in shoots and roots were not correlated among Caryophyllales species with normal [Na]shoot, but were positively correlated among Caryophyllales species with abnormally large [Na]shoot. In addition, Caryophyllales species with abnormally large [Na]shoot had greater [Na]shoot/[Na]root than Caryophyllales species with normal [Na]shoot. Conclusions Sodium hyperaccumulators in the Caryophyllales are characterized by abnormally large [Na]shoot, a positive correlation between [Na]shoot and [Na]root, and [Na]shoot/[Na]root quotients greater than unity.
37
Billings, Sharon G., Chee K. Chin e Gojko Jelenkovic. "Regeneration of Blueberry Plantlets from Leaf Segments". HortScience 23, n. 4 (agosto 1988): 763–66. http://dx.doi.org/10.21273/hortsci.23.4.763.
Testo completoAbstract (sommario):
Abstract A procedure to regenerate shoots in vitro from leaf sections of two blueberry genotypes, ‘Berkeley’ and ‘Bluehaven’, in Woody Plant Medium was established. The effect of 20 combinations of growth regulators: NAA at 0, 1, 2, and 4 µM and 2iP at 0, 5, 10, 15, and 20 µM were compared. Combinations containing NAA generally promoted callus formation and suppressed shoot regeneration. Conversely, media containing cytokinin promoted shoot regeneration and suppressed callus formations. The optimal medium for shoot regeneration contained 15 µM 2iP but no NAA. This procedure was highly efficient (70%–100%) in producing large numbers of shoots in a relatively short period (4 weeks). Chemical names used: N-(3-methyl-2-butenyl)-1-H-purine-6-amine (2iP); 2-(l-naphthyl)acetic acid (NAA).
38
Criley*, Richard A. "Seasonal Flowering of Heliconia ×rauliniana". HortScience 39, n. 4 (luglio 2004): 882C—882. http://dx.doi.org/10.21273/hortsci.39.4.882c.
Testo completoAbstract (sommario):
As part of a research study on growth and flower production of 20 commercial heliconia cultivars, plants were established at the Waimanalo Research Farm (Oahu) of the Univ. of Hawaii in July 1999. This report focuses on Heliconia ×rauliniana. Five plants in 7.6 L pots were planted at spacings of 2.5 M in row, with between row spacings of 3 M. Beginning a month later, newly emerged shoots were tagged every four weeks. At flowering, the shoots were harvested and leaf counts made. The information derived from the data include time frame from shoot emergence to flower, rate of shoot production, percentage of shoots from each tag date that flowered and the periodicity of flowering in a two year period. The range of times from shoot emergence to harvest was 208 to 450 days. In the first 12 months following planting, the average cumulative new shoot production since planting was 77 shoots per plant, while more than 58 inflorescences per plant were produced from the tagged stems for a 75% productivity rating. H. X rauliniana evidenced periodic flowering behavior, with peak flowering in the April to June period, that suggested it is a short-day plant for flower initiation.
39
Sabatier, Sylvie, Daniel Barthélémy, Isabelle Ducousso e Éric Germain. "Modalités d'allongement et morphologie des pousses annuelles chez le noyer commun, Juglans regia L. 'Lara' (Juglandaceae)". Canadian Journal of Botany 76, n. 7 (1 luglio 1998): 1253–64. http://dx.doi.org/10.1139/b98-055.
Testo completoAbstract (sommario):
Shoot extension during a growth season has been investigated in three morphological types of floriferous annual shoots (monocyclic with or without a small axis with immediate development and bicyclic) on four types of parental branches within 4-year-old Juglans regia L. 'Lara' growing in the south-west of France. The morphological type of parental branches has an influence on the time of inception of monocyclic shoot extension. No correlation has been found between the parental shoot length and monocyclic shoot length, while a positive correlation has been found between parental shoot length and bicyclic shoot length. Bicyclic annual shoots expand during two successive flushes : in spring and summer, respectively. The intra-annual resting phase results in the presence of a series of cataphylls in the median part of the shoots. Spring shoots and summer shoots may be distinguished by variations in form and in number of foliar organs. Annual shoots exhibiting an acrotonic axis with immediate development or a summer shoot generally possess greater extension periods and lengths of spring shoots than the unbranched ones.Key words: Juglans regia 'Lara', persian walnut, shoot extension, primary growth, morphology, annual shoot.
40
Liu, Huihui, Cheng Zhang, Yanqiong Meng, Fengyu Zhang, Nuo Huang, Jianan Wang e Yiyong Li. "Hydraulic and Economical Traits in Short- and Long-Shoot Leaves of Ginkgo biloba Males and Females". Forests 14, n. 3 (8 marzo 2023): 535. http://dx.doi.org/10.3390/f14030535.
Testo completoAbstract (sommario):
Ginkgo biloba is a dioecious heterophyllous tree species with two leaf types. Short shoots always bear many leaves, which are undivided or slightly bilobed, but long-shoot leaves are smaller and are deeply divided into two or more lobes. To clarify the functional difference between the two leaf types, we investigated the morphology, anatomy, gas exchange, and hydraulic traits of the two leaf types in male and female trees. Our results showed that long-shoot leaves possessed a lower specific leaf area (SLA), higher leaf thickness, gas exchange rates, and average tracheid number than short-shoot leaves. When compared to short-shoot leaves, long-shoot leaves in male trees had higher leaf hydraulic conductance (Kleaf) and leaf water potential of 50% loss in Kleaf (leaf P50), while female trees exhibited relatively higher Kleaf. When comparing sexual differences, male trees possessed higher leaf thickness, leaf dissection index, vein density (VD), and predawn leaf water potential and lower SLA, tracheid number, and midday leaf water potential, while no significant difference in leaf P50 was observed between the two sexes. Male trees exhibited greater leaf gas exchange rates, which were tightly associated with other functional traits, such as VD and Kleaf. We found strong shoot-based and sex-related heterogeneities in the leaf hydrology, anatomy, and economy of Ginkgo biloba. Moreover, male ginkgoes may perform better due to their greater leaf hydraulic efficiency and gas exchange rates.
41
Skupchenko, V. B. "Changes in the Shoot Apical Meristem with Decrease in Illumination within the Crown of <i>Pseudotsuga menziesii</i> (Pinaceae) Introduced in St. Petersburg". Растительные ресурсы 59, n. 4 (1 ottobre 2023): 378–93. http://dx.doi.org/10.31857/s0033994623040118.
Testo completoAbstract (sommario):
Abstract—In Pseudotsuga menziesii Mirb. Franco introduced in St. Petersburg, the changes in the apical meristem morphogenesis during the formation of a short bud shoot with covering scales and meristematic primordium of shoot with needles, under the decrease in illumination within the crown were studied. Terminal 1–4-year-old shoots of the third-order branches in the lower part of the crown with a relative light availability (RLA) in the range of 23.9–18.3% perform full annual cycle of morphogenesis of the shoot apical meristem. Before each stage of morphogenesis, the apical meristem performs independent volume growth associated with the formation of mother groups of phytomer cells of covering scales and needles in the peripheral meristem. With RLA reducing to 15.1–15.4%, in terminal 5–6-year-old shoots over the growing season, the apical meristem performs only formation of a short bud shoot with covering scales and stops volume growth. This is because in the vascular bundles of the stele of the short bud stem, the sieve cells of the phloem are not formed, and the xylem part is poorly developed. The direct contact of the apex with the stele of the bud stem is blocked by procambium bundles, since their cells are differentiated and crystalline cellulose is accumulated in the cell walls. The cell walls of the bark parenchyma of the short bud stem contains significantly less birefringent inclusions, and only single small resin receptacles.
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Mickle, James E. "The Evolutionary Relevance of Vegetative Long-shoot/short-shoot Differentiation in Gymnospermous Tree Species". Journal of North Carolina Academy of Science 129, n. 1 (1 marzo 2013): 36. http://dx.doi.org/10.7572/2167-5880-129.1.36.
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Frett, John J., e Richard McCardell. "TIMING OF CYTOKININ MEDIATED SHOOT INITIATION". HortScience 25, n. 9 (settembre 1990): 1108G—1108. http://dx.doi.org/10.21273/hortsci.25.9.1108.
Testo completoAbstract (sommario):
Several cytokinins at various concentrations were tested to determine which would stimulate the most synchronous shoot initiation. Kinetin was effective only at concentrations of 50 mg/L, while 2iP and zeatin where effective from 5 to 50 mg/L. BA at 10 mg/L produced the most synchronous and the greatest number of shoots. This treatment was used to determine at what point in development cytokinins stimulate shoots. Tissue was grown in the presence and absence of BA for various lengths of time. Application of BA for at least 10 days was required to initiate shoots. Explants were not effected by BA during the first 5 days of culture. Starving tissue for various periods caused a proportional lag in shoot production. Short pulses of BA at different developmental stages did not alter the cytokinin response. Vacuum infiltration of cytokinins prior to culture did not increase the BA response.
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Frett, John J., e Richard McCardell. "TIMING OF CYTOKININ MEDIATED SHOOT INITIATION". HortScience 25, n. 9 (settembre 1990): 1108g—1108. http://dx.doi.org/10.21273/hortsci.25.9.1108g.
Testo completoAbstract (sommario):
Several cytokinins at various concentrations were tested to determine which would stimulate the most synchronous shoot initiation. Kinetin was effective only at concentrations of 50 mg/L, while 2iP and zeatin where effective from 5 to 50 mg/L. BA at 10 mg/L produced the most synchronous and the greatest number of shoots. This treatment was used to determine at what point in development cytokinins stimulate shoots. Tissue was grown in the presence and absence of BA for various lengths of time. Application of BA for at least 10 days was required to initiate shoots. Explants were not effected by BA during the first 5 days of culture. Starving tissue for various periods caused a proportional lag in shoot production. Short pulses of BA at different developmental stages did not alter the cytokinin response. Vacuum infiltration of cytokinins prior to culture did not increase the BA response.
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Al-Drisi, Emad E., Majid A. Ibrahim e Abbas M. Jasim. "Impact of Different Sucrose Concentrations on Shoot Multiplication of Papaya (Carica papaya L.) Cultured in vitro". Basrah Journal of Agricultural Sciences 35, n. 2 (22 dicembre 2022): 240–47. http://dx.doi.org/10.37077/25200860.2022.35.2.17.
Testo completoAbstract (sommario):
Papaya is a heterozygous plant commonly cultivated by seed but, unfortunately, they are not true to type. Moreover, the hybrid seed varieties like the Red Lady are very highly expensive. Hence, tissue culture techniques offer an alternative method to produce a million clones within a short period and a reasonable price. Thus, the current study aimed to optimize the shoot multiplication rate of papaya (Carica papaya L. cv. Red Lady) in vitro. Five concentrations of sucrose (10, 20, 30, 40, and 50 g.L-1) were applied for the papaya shoot proliferation. Results demonstrated that the 30 g.L-1 sucrose was significantly superior in the rate of shoot numbers (4.1 shoots. explant-1), shoot length (0.90 cm), (2.7 leaves. shoot-1), leaf area (1.40 cm2) and fresh weight (0.192 g) in compared with other sucrose treatments. Whereas, the 40 g.L-1 sucrose treatment was significantly superior in dry weight of shoot compared to the other treatments, which recorded 0.058 g. While the treatment of 10 g.L-1 sucrose recorded the lowest values in shoot numbers, length, and dry weight. Current study conclude that the 30 g.L-1 sucrose is the best concentration treatment that must be used in papaya micropropagation, where it gives the maximum rate of shoot numbers and other morphological traits.
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Crabbe, Jacques J. "Episodic Growth and Shoot Differentiation in Apple (Malus ×domestica Borkh.)". HortScience 31, n. 4 (agosto 1996): 603b—603. http://dx.doi.org/10.21273/hortsci.31.4.603b.
Testo completoAbstract (sommario):
The flushing behavior of shoot growth and its consequences on shoot differentiation are important features in fruit tree development, with regard to flowering ability. In this respect, two different approaches were applied to young `M26' apple trees. First, poorly branched 2-year-old trees were headed back, either in the second-year or in the first-year wood, at different times from right before to 6 weeks after budbreak. Early pruning resulted in rapid and prolonged regrowth, with a final very similar shaping of the tree to that of the intact controls. Late pruning, in contrast, leads to a two-step reaction (late spring and summer flushes), sometimes stronger on 2-year-old than on 1-year-old wood. In a second experiment, buds and young shoots were sampled on pruned trees in locations where they could be supposed to remain short shoots or grow long, with one or two flushes. They were weighed, their leaves and internodes measured, and the plastochron evaluated. During budbreak and the first month afterwards, shoot differentiation appears achieved. The primary difference between long and short shoot types does not consist in faster internode elongation but, rather, in faster production (reduced plastochron) of larger leaves.
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Johnson, R. S., e A. N. Lakso. "Carbon Balance Model of a Growing Apple Shoot: II. Simulated Effects of Light and Temperature on Long and Short Shoots". Journal of the American Society for Horticultural Science 111, n. 2 (marzo 1986): 164–69. http://dx.doi.org/10.21273/jashs.111.2.164.
Testo completoAbstract (sommario):
Abstract A computer model of a growing apple (Malus domestica Borkh.) shoot was used to estimate the effects of light and temperature on the C balance of a shoot. Long-term average solar radiation (langley/day) and maximum and minimum temperatures from Geneva, N.Y., were used as weather inputs. To simulate other weather conditions, solar radiation was increased or decreased by 150 langley/day, and maximum and minimum temperatures increased or decreased by 5.6°C. Both a short shoot of 2 cm and a long shoot of 50 cm final length were simulated. The model output indicated that increased light reduced carbohydrate import and caused earlier and greater export. Increased temperature increased carbohydrate import and the subsequent rate of carbohydrate export. The short shoot had a greater initial rate of C export and continued to export more total carbohydrates than the long shoot for about 30 to 50 days after budbreak. Slow leaf area development at a given temperature had little effect on carbohydrate import but delayed the beginning of export.
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Rybczyński, Jan J., Marta Karolkowska, Zygmunt Kaczmarek, Anna Mikuła e Agnieszka Fiuk. "In vitro morphogenic events in culture of Lotus corniculatus L. seedling root explants". Acta Societatis Botanicorum Poloniae 75, n. 3 (2011): 191–200. http://dx.doi.org/10.5586/asbp.2006.022.
Testo completoAbstract (sommario):
The experiments were carried out on <em>Lotus corniculatus</em> (L.) seedling root explants of the cultivar varieties Skrzeszowicka, Caroll A10 and strain 175. Callus formation and shoot regeneration were the major explant response depended mainly on of the studied genotype and used plant growth regulators (PGRs). Primary cortex of proximal and distal end of explant was the most active tissue for callus proliferation. For shoot primordia differentiation deeper zones of cortex took a part. The process of meristematic centre initiation was not uniform and various level of shoot differentiation events were observed not earlier than 3 weeks of culture. Usually, the shoot primordia regeneration began on proximal rather than distal end of the explant. BAP rather than urea derivatives stimulated shoot proliferation in extended cultures. Increasing of BAP and TDZ concentrations brought about the explant polarity and expansion of the meristematic zones. The explant position in root did not have significant influence on the number of regenerated shoots. The cultures only had better bud formation by TDZ when compared to BAP. BAP stimulated bud formation and development of the shoots from them. Short term of TDZ treatment of explants stimulated meristem formation which developed into buds and shoots. CPPU stimulated callus proliferation and bud formation when explants pretreatment was prolonged from 12 to 36 hrs.
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Pant, Bijaya, e Sangeeta Swar. "Micropropagation of Cymbidium iridioides". Nepal Journal of Science and Technology 12 (22 luglio 2012): 91–96. http://dx.doi.org/10.3126/njst.v12i0.6485.
Testo completoAbstract (sommario):
Seeds of Cymbidium iridioides D. Don, a highly collected orchid species of Nepal, has been developed were cultured on Murashige and Skoog, 1962 (MS) static media solidified with 0.8% agar. Complete seedlings were obtained from asymbiotically germinated seeds on MS media supplemented with 6- benzyalaminopurine (BAP) 1 mg/l plus ?-naphthaleneacetic acid (NAA) 1 mg/l in eight weeks of primary culture. The shoot tip explants were obtained from in vitro grown seedling for the shoot multiplication. Maximum number of shoots were developed from shoot tip explants on MS media supplemented with BAP 0.5 mg/l (8.25 shoots per single shoot). This ability did not decline even after a year of subculture. For rooting of shoots the media was supplemented with various auxins. Media supplemented with 1mg/l indole-3-butyric acid (IBA) was the ideal condition for root formation. Thus obtained complete plantlets were able to grow in community pots after a short period of acclimatization. This result suggests that the methodology might be applied as an alternative to minimize the over exploitation of the natural population of this species.DOI: http://dx.doi.org/10.3126/njst.v12i0.6485 Nepal Journal of Science and Technology 12 (2011) 91-96
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Minichin, P. E. H., M. R. Thorpe e J. F. Farrar. "Short-term control of root: shoot partitioning". Journal of Experimental Botany 45, n. 5 (1994): 615–22. http://dx.doi.org/10.1093/jxb/45.5.615.
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