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水分是决定植物分布与作物生产力的主要因素之一。水分缺乏可引起植物生命活动的各个方面,包括生长发育、形态解剖与生理代谢等的改变,但是它的最主要而直接的影响是对生长发育的改变。生长调节物质对植物的生长发育有广泛的调节作用。因此关于植物在水分胁迫条件下,内源激素发生什么变化以及激 相似文献
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植物生长调节物质的研究进展 总被引:21,自引:0,他引:21
述评了近几年国内外在植物激素与植物体内信使的传递、植物激素与基因诱导和表达、植物生长物质的复合使用、新型植物生长物质的开发及植物激素对提高植物抗逆性的作用等方面的研究进展,并展望了植物生长物质的发展趋势。 相似文献
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几种新型植物内源生长调节物质 总被引:7,自引:0,他引:7
扼要介绍了系统素,茉莉酸,寡糖素,水杨酸,油菜素内酯和玉料赤霉烯酮等甾类激素,膨压素,多胺,乙酰胆碱等几种新型植物的内源生长调节物质。 相似文献
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活性碳对培养基中植物生长调节物质的吸附作用 总被引:5,自引:0,他引:5
植物组织和细胞培养中经常使用活性碳(Johansson等1982,Fridborg和Eriksson 1975,Smith 1983,Steinitz和 Yahel 1982)。一般认为活性碳通过吸附而发生作用(Fridborg和Erik-sson 1975,Kohlenbach 和 Wernicke 1978,Martineau等1981)。但关于活性碳吸附何种 相似文献
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Soraya Guichard Christian Gary Cherubino Leonardi Nadia Bertin 《Journal of Plant Growth Regulation》2005,24(3):201-213
The influence of air vapor pressure deficit (VPD) and plant fruit load on the expansion and water relations of young tomato
fruits grown in a glasshouse were evaluated under summer Mediterranean conditions. The contributions of phloem, xylem and
transpiration fluxes to the fruit volume increase were estimated at an hourly scale from the growth curves of intact, heat-girdled
and detached fruits, measured using displacement transducers. High VPD conditions reduced the xylem influx and increased the
fruit transpiration, but hardly affected the phloem influx. Net water accumulation and growth rate were reduced, and a xylem
efflux even occurred during the warmest and driest hours of the day. Changes in xylem flux could be explained by variations
in the gradient of water potential between stem and fruit, due to changes in stem water potential. Misting reduced air VPD
and alleviated the reduction in fruit volume increase through an increase in xylem influx and a decrease in fruit transpiration.
Under low fruit load, the competition for assimilates being likely reduced, the phloem flux to fruits increased, similarly
to the xylem and transpiration fluxes, without any changes in the fruit water potential. However, different diurnal dynamics
among treatments assume variable contributions of turgor and osmotic pressure in F3 and F6 fruits, and hypothetical short-term
variations in the water potential gradient between stem and fruit, preventing xylem efflux in F3 fruits. 相似文献
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糖和脱落酸及乙烯互作及其与植物生长发育的关系 总被引:2,自引:1,他引:2
从分子角度介绍和讨论了植物(主要是拟南芥)生长发育过程中,植物糖信号的复杂信号网络和作用,特别是它与脱落酸和乙烯合成的关系. 相似文献
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The changes in leaf extension, plant dryweight, leaf area, netassimilation rate (E), relative growth-rate (RW), and relativeleaf growth-rate (RL), have been studied for four species grownfor 2 weeks in solutions of polyethylene glycol 4000 of controlledosmotic potentials. All aspects of growth were decreased bydecreasing the osmotic potential (sol) of the root medium andthe leaf water potential (), and ceased when / was greater than 10 bars in bean, cotton, maize. These plants were moresusceptible than ryegrass to water stress. Growth of bean stoppedat equal to about 6 bars, but even at 10 barsryegrass was capable of some growth. Slight decrease in fromthe values in the control plants decreased growth during thefirst week but partial recovery was apparent during the secondweek's growth in solution culture, when leaf extension, E, RLand RW increased in plants subjected to stress. Examinationof the water balance, water potential, osmotic potential andturgor of the leaf in relation to relative water content suggeststhat recovery was related to increased turgor and that the abilityof the plants to grow at reduced values of the osmotic potentialof the root medium and of the leaf water potential depend onthe maintenance of turgor. 相似文献
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Rhizosphere Microbial Community Structure in Relation to Root Location and Plant Iron Nutritional Status 总被引:15,自引:1,他引:15 下载免费PDF全文
Root exudate composition and quantity vary in relation to plant nutritional status, but the impact of the differences on rhizosphere microbial communities is not known. To examine this question, we performed an experiment with barley (Hordeum vulgare) plants under iron-limiting and iron-sufficient growth conditions. Plants were grown in an iron-limiting soil in root box microcosms. One-half of the plants were treated with foliar iron every day to inhibit phytosiderophore production and to alter root exudate composition. After 30 days, the bacterial communities associated with different root zones, including the primary root tips, nonelongating secondary root tips, sites of lateral root emergence, and older roots distal from the tip, were characterized by using 16S ribosomal DNA (rDNA) fingerprints generated by PCR-denaturing gradient gel electrophoresis (DGGE). Our results showed that the microbial communities associated with the different root locations produced many common 16S rDNA bands but that the communities could be distinguished by using correspondence analysis. Approximately 40% of the variation between communities could be attributed to plant iron nutritional status. A sequence analysis of clones generated from a single 16S rDNA band obtained at all of the root locations revealed that there were taxonomically different species in the same band, suggesting that the resolving power of DGGE for characterization of community structure at the species level is limited. Our results suggest that the bacterial communities in the rhizosphere are substantially different in different root zones and that a rhizosphere community may be altered by changes in root exudate composition caused by changes in plant iron nutritional status. 相似文献
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Cacao (Theobroma cacao L.) seedlings at the onset of a flushcycle were exposed to five different irrigation treatments.The expansion of all leaves in an emerging flush was followed,and estimates of leaf water potential(w) were made on each daythat leaf areas were measured. The growth in area of the leaveswas fitted with a modified logistic curve of the form y = a/[1+ be (ct+dt2)], and parameters of leaf growth were derivedfrom the fitted constants. A coefficient of stress exposure,S, was derived as the slope of the relation between cumulativew and time. Three parameters of the logisitc function (a, cand d) were strongly associated with S. By fitting regressionsfor the relations between S and estimates of each parameterfor the five treatments, values of a, b, c and d may be estimatedat any level of S encompassed by these data. The effects ofwater stress on leaf expansion rate and on the final leaf areaattained by the emerging flush can be adequately predicted bythis technique. Theobroma cacao L.cacao, leaf expansion, logistic model, water stress 相似文献
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The Intracellular Water Activity of Bacteria in Relation to the Water Activity of the Growth Medium 总被引:1,自引:1,他引:0
Intracellular water activities ( a w ) calculated from the solute composition of various bacterial cells, are in good agreement with values derived from intracellular freezing point data. Further, and confirming literature results based on freezing points, the intracellular a w was found to be generally equal to or lower than that of the growth medium. 相似文献
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E.-D. Schulze 《Plant biology (Stuttgart, Germany)》1983,96(1):391-402
Morphological features of arid region plant life forms are described and interpreted as adaptations to drought although this cannot be easily quantified. Functional adaptations, however, can be measured, and using the annual crop plant Vigna unguiculata (L.) Walp. responses to drought are described at the leaf and the whole plant level. In the first step of this analysis theoretical criteria are developed to define optimal water use. In the second step experimental data are used to test to what extent Vigna follows a theoretically optimal regulation of water and carbon relations. The analysis indicates that the ecological adaptation of regulatory processes may be quantified at a functional level. 相似文献
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L. D. Hansen R. W. Breidenbach B. N. Smith J. R. Hansen R. S. Criddle 《Plant biology (Stuttgart, Germany)》1998,111(4):255-260
Abstract: The relation between plant growth rate and respiration rate is readily derived from the overall chemical reaction for aerobic metabolism. The derived relation can be used to show that separation of respiration into growth (g) and maintenance (m) components is not a useful concept. g and m cannot be unambiguously measured or defined in terms of biochemical processes. Moreover, because growth yield calculations from biochemical pathway analysis, from biomass molecular composition, from biomass heat of combustion, and from biomass elemental composition have not included all of the energy costs for biosynthesis, they are not accurate measures of the carbon cost for plant growth. Improper definitions of growth-respiration relations are impeding the use of physiological properties for prediction of plant growth as a function of environmental variables. 相似文献