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1.
The effect of CO2 concentration elevated to 575 – 620 µmol mol–1 on growth, tillering, grain yield, net photosynthetic rate, dark respiration rate, stomatal conductance, sugar content and protein profile of two rice (Oryza sativa L.) cultivars Pusa Basmati-1 and Pusa-677 at flowering stage was studied using open top chambers. The cultivar Pusa Basmati-1 responded more markedly for most of the growth and physiological parameters compared to Pusa-677. The increase in grain yield in Pusa Basmati-1 attributed largely to increased grain number. The increased net photosynthetic rate and greater accumulation of sugar contributed significantly to the accelerated development of leaves and tillers in both the cultivars. The reduction in the low molecular mass proteins including Rubisco and increase in high molecular mass photosystem 2 proteins was observed in both the cultivars. Additional sugars may possibly help in balancing the profile of photosynthetic proteins and sustain greater growth and productivity in rice cultivars.  相似文献   

2.
Leaf stomatal density (SD), net photosynthetic rates (P N), and stomatal conductance (g s) of Hordeum vulgare and Pisum sativum cultivars in Himalaya increased with altitude. Higher P N and leaf temperature under low CO2 partial pressure at high altitudes could evoke a higher g s and SD to allow sufficient influx of CO2 as well as more efficient leaf cooling through transpiration.  相似文献   

3.
水稻剑叶气孔性状与孕穗期耐冷性的关系研究   总被引:3,自引:0,他引:3  
以人工气候室鉴定的孕穗期耐冷性不同的10个水稻品种为材料,采用扫描电子显微镜观测其剑叶的气孔密度、气孔大小和单位面积气孔周长等性状特点,以探讨水稻剑叶气孔性状与孕穗期耐冷性的关系.结果表明:耐冷性强品种'培杂软香'、'天优688'、'冈优825' 的气孔密度和单位叶面积气孔总周长较小,分别为380~410个/mm2和29.8~32.6 cm;耐冷性弱的品种'粤杂763'气孔密度和单位叶面积气孔总周长较大,分别为618个/mm~2和46.9 cm; 耐冷性中等的品种'培杂泰丰'等介于二者之间,分别为460~510个/mm~2和35.1~39.3 cm.气孔密度相近时,气孔较大的品种耐冷性较弱;单位叶面积气孔总周长相近时,气孔密度大的品种耐冷性较弱.研究发现,水稻品种剑叶的气孔密度和单位叶面积气孔总周长与其孕穗期耐冷性均呈极显著正相关,可以作为水稻孕穗期耐冷性的鉴定指标.  相似文献   

4.
Cultivar differences in leaf photosynthesis of rice bred in Japan   总被引:9,自引:0,他引:9  
The grain yield of rice (Oryza sativa L.), as well as of other cereal crops, is limited to a large extent, by the supply of photosynthates produced during grain filling period. In this study, flag leaf photosynthesis (LPS) after heading was compared among 32 cultivars bred during the past century in Japan, to determine if the improvement of LPS has occurred with the breeding advance of high yielding cultivars. Measurement of LPS was made for 5 consecutive years in the paddy field, on the flag leaf of the main stem, at heading (LPS-0), and 2 weeks (LPS-2) and 4 weeks (LPS-4) after heading. LPS decreased with advance of leaf senescence from LPS-0 to LPS-2, and then to LPS-4. However, if nitrogen was top-dressed at the heading time, high LPS-2 was maintained, particularly in the newer cultivars. A significant positive correlation between LPS and the released year of cultivar was found at LPS-2, especially in the nitrogen top-dressed plot, but not at LPS-0 or LPS-4. Cultivar difference in LPS of the senescing leaves were not stable through the different years, whereas LPS-0 was stable over years, suggesting that the LPS in the senescent leaf is susceptible to the environmental variation due to the effects on leaf senescence. Cultivar difference in LPS at any stage was closely associated with mesophyll conductance to CO2, and stomatal conductance was also associated with cultivar difference in such a high LPS as LPS-0 and nitrogen top-dressed LPS-2. Significant correlation between LPS and specific leaf weight was not observed at any stage of the flag leaf.Abbreviations CV coefficient of variation - gm mesophyll conductance - gs stomatal conductance - LPS apparent photosynthetic rate per unit leaf area (leaf photosynthesis) - LPS-0 LPS at heading - LPS-2 LPS at active grain filling - LPS-4 LPS at maturity of grain - NT non-top dressed plot - PPFD photosynthetic photon flux density - rm mesophyll resistance - rs stomatal diffusion resistance against CO2 - rs(H2O) stomatal diffusion resistance against H2O - RuBisCO ribulose-1,5-bisphosphate carboxylase/oxygenase - SLW specific leaf weight - TD nitrogen top-dressed plot  相似文献   

5.
The ontogenetic changes in stomatal size, frequency and conductance (gs) on abaxial and adaxial leaf surfaces of sunflower plants (Helianthus annuus L. Russian Mammoth) were examined under controlled environmental conditions. The stomatal frequency on the adaxial and abaxial leaf surfaces decreased with leaf ontogeny and insertion level. The ratio of adaxial to abaxial stomatal frequency did not change with leaf ontogeny and insertion level, and 42–44% of total stomata was apportioned to the adaxial surface. Ontogenetic changes in stomatal pore length were detected and increased with ontogenesis. The stomatal length of both leaf surfaces had linear relationships with leaf area. Ontogenetic changes in gs were similar between the two surfaces. However the adaxial gs was lower than abaxial gs in leaves of higher insertion levels. Conductance had a linear relationship with width x frequency but not with pore area.  相似文献   

6.
M. Pollok  U. Heber  M. S. Naik 《Planta》1989,178(2):223-230
When leaves of Helianthus annuus, whose stomates had been opened in the dark in the absence of CO2, were exposed to 25% carbon monoxide (CO), stomatal conductivity for water vapor decreased from about 0.4 to 0.2 cm·s-1. The CO effect on stomatal aperture required a CO/O2 ratio of about 25. As this ratio was decreased the stomata opened, indicating that inhibitio of cytochrome-c oxidase by CO is competitive in respect to O2. Photosynthetically active red light was unable to reverse CO-induced stomatal closure even at high irradiances, when CO2 was absent. When it was present, stomatal opening was occasionally, but not consistently observed. Carbon monoxide did not inhibit photosynthetic carbon reduction in leaves of Helianthus.In contrast to red light, very weak blue light (405 nm) increased the stomatal aperture in the presence of CO. It also increased leaf ATP/ADP ratios which had been decreased in the presence of CO. The blue-light effect was not related to photosynthesis. Neither could it be explained by photodissociation of the cytochrome a 3-CO complex which has an absorption maximum at 430 nm. The data indicate that ATP derived from mitochondrial oxidative phosphorylation provides energy for stomatal opening in sunflower leaves in the dark as well as in the light. Indirect transfer of ATP from chloroplasts to the cytosol via the triose phosphate/phosphoglycerate exchange which is mediated by the phosphate translocator of the chloroplast envelope can support stomatal opening only if metabolite concentrations are high enough for efficient shuttle transfer of ATP. Blue light causes stomatal opening in the presence of CO by stimulating ATP synthesis.  相似文献   

7.
春小麦对不同灌水处理的气孔反应及其影响因子   总被引:5,自引:0,他引:5  
选用3个春小麦品种(系),采用大田试验方法,在冬灌1800 m3·hm-2的基础上,在生育期设3次灌水处理(T1)、2次灌水处理(T2)和1次灌水处理(T3),每次灌水1050 m3·hm-2,研究土壤水分对春小麦生育期气孔导度的影响及气孔导度与相关环境因素的关系.结果表明:灌水处理对春小麦生育期气孔导度的影响较大,气孔导度随着灌溉次数的减少逐渐降低,同时不同基因型间存在差异.从拔节期到开花期,不同处理春小麦气孔导度变化一致,都呈先升高后降低趋势, 在抽穗期达到峰值;开花期之后各处理出现差异,T1各品种气孔导度先下降后上升,T2品种间表现不同,T3一直呈下降趋势.各环境因子中,大气相对湿度对春小麦气孔导度的影响最大,两者的相关系数在T2和T3中分别达显著(0.82*)和极显著水平(0.92**).春小麦适应水分亏缺的气孔调节机理为反馈式调节.  相似文献   

8.
Engloner  A.I.  Kovács  D.  Balogh  J.  Tuba  Z. 《Photosynthetica》2003,41(2):185-189
Leaf anatomy and eco-physiology of Elymus repens, a temperate loess grassland species, were determined after seven years of exposure to 700 μmol (CO2) mol−1 (EC). EC treatment resulted in significant reduction of stomatal density on both surfaces of couch-grass leaves. Thickness of leaves and that of the sclerenchyma tissues between the vessels and the adaxial surfaces, the area of vascular bundle, and the volumes of phloem and tracheary increased at EC while abaxial epidermis and the sclerenchyma layer between the vessel and the abaxial surface were thicker at ambient CO2 concentration (AC). Stomatal conductance and transpiration rates were lower in EC, while net CO2 assimilation rate considerably increased at EC exposure. Contents of soluble sugars and starch were higher in EC-treated couch-grass leaves than in plants grown at AC. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

9.
徐燕  杨颖  玄晓丽  王永飞 《广西植物》2011,31(1):124-128
以"油青60天"和"四九-19"2个菜心品种为材料,研究了菜心下胚轴气孔特征、气孔密度和气孔指数在2年内随不同发育时间的变化情况.结果显示:菜心种子萌发后第3天,下胚轴表皮上已有椭圆形或狭长形的气孔分布;菜心下胚轴普通表皮细胞为长条形,排列紧密."油青60天"和"四九-19"下胚轴的平均气孔密度均先下降后上升,分别在第...  相似文献   

10.
Olive (Olea europea L) is one of the most valuable and widespread fruit trees in the Mediterranean area. To breed olive for resistance to salinity, an environmental constraint typical of the Mediterranean, is an important goal. The photosynthetic limitations associated with salt stress caused by irrigation with saline (200 mm ) water were assessed with simultaneous gas‐exchange and fluorescence field measurements in six olive cultivars. Cultivars were found to possess inherently different photosynthesis when non‐stressed. When exposed to salt stress, cultivars with inherently high photosynthesis showed the highest photosynthetic reductions. There was no relationship between salt accumulation and photosynthesis reduction in either young or old leaves. Thus photosynthetic sensitivity to salt did not depend on salt exclusion or compartmentalization in the old leaves of the olive cultivars investigated. Salt reduced the photochemical efficiency, but this reduction was also not associated with photosynthesis reduction. Salt caused a reduction of stomatal and mesophyll conductance, especially in cultivars with inherently high photosynthesis. Mesophyll conductance was generally strongly associated with photosynthesis, but not in salt‐stressed leaves with a mesophyll conductance higher than 50 mmol m?2 s?1. The combined reduction of stomatal and mesophyll conductances in salt‐stressed leaves increased the CO2 draw‐down between ambient air and the chloroplasts. The CO2 draw‐down was strongly associated with photosynthesis reduction of salt‐stressed leaves but also with the variable photosynthesis of controls. The relationship between photosynthesis and CO2 draw‐down remained unchanged in most of the cultivars, suggesting no or small changes in Rubisco activity of salt‐stressed leaves. The present results indicate that the low chloroplast CO2 concentration set by both low stomatal and mesophyll conductances were the main limitations of photosynthesis in salt‐stressed olive as well as in cultivars with inherently low photosynthesis. It is consequently suggested that, independently of the apparent sensitivity of photosynthesis to salt, this effect may be relieved if conductances to CO2 diffusion are restored.  相似文献   

11.
A. Schwartz  E. Zeiger 《Planta》1984,161(2):129-136
The supply of energy for stomatal opening was investigated with epidermal peels of Commelina communis L. and Vicia faba L., under white, blue and red irradiation or in darkness. Fluencerate response curves of stomatal opening under blue and red light were consistent with the operation of two photosystems, one dependent on photosynthetic active radiation (PAR) and the other on blue light, in the guard cells. The PAR-dependent system was 3(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU)-sensitive and KCN-resistant and showed a relatively high threshold irradiance for its activation; its activity was most prominent at moderate to high irradiances. The blue-light-dependent photosystem was KCN-sensitive, was active at low irradiances, and interacted with the PAR-dependent photosystem at high blue irradiances. Stomatal opening in darkness, caused by CO2-free air, fusicoccin or high KCl concentrations, was KCN-sensitive and DCMU-resistant. These data indicate that stomatal opening in darkness depends on oxidative phosphorylation for the supply of high-energy equivalents driving proton extrusion. Light-dependent stomatal opening appears to require photophosphorylation from guard-cell chloroplasts and the activation of the blue-light photosystem which could rely either on oxidative phosphorylation or a specific, membrane-bound electron-transport carrier.Abbreviations DCMU 3(3,4-dichlorophenyl)-1-1-dimethylurea - FC fusicoccin - KCN potassium cyanide - PAR photosynthetic active radiation - WL white light  相似文献   

12.

Background and Aims

Stomata formed at high relative air humidity (RH) respond less to abscisic acid (ABA), an effect that varies widely between cultivars. This study tested the hypotheses that this genotypic variation in stomatal responsiveness originates from differential impairment in intermediates of the ABA signalling pathway during closure and differences in leaf ABA concentration during growth.

Methods

Stomatal anatomical features and stomatal responsiveness to desiccation, feeding with ABA, three transduction elements of its signalling pathway (H2O2, NO, Ca2+) and elicitors of these elements were determined in four rose cultivars grown at moderate (60 %) and high (90 %) RH. Leaf ABA concentration was assessed throughout the photoperiod and following mild desiccation (10 % leaf weight loss).

Key Results

Stomatal responsiveness to desiccation and ABA feeding was little affected by high RH in two cultivars, whereas it was considerably attenuated in two other cultivars (thus termed sensitive). Leaf ABA concentration was lower in plants grown at high RH, an effect that was more pronounced in the sensitive cultivars. Mild desiccation triggered an increase in leaf ABA concentration and equalized differences between leaves grown at moderate and high RH. High RH impaired stomatal responses to all transduction elements, but cultivar differences were not observed.

Conclusions

High RH resulted in decreased leaf ABA concentration during growth as a result of lack of water deficit, since desiccation induced ABA accumulation. Sensitive cultivars underwent a larger decrease in leaf ABA concentration rather than having a higher ABA concentration threshold for inducing stomatal functioning. However, cultivar differences in stomatal closure following ABA feeding were not apparent in response to H2O2 and downstream elements, indicating that signalling events prior to H2O2 generation are involved in the observed genotypic variation.  相似文献   

13.
Tognetti  R.  Sebastiani  L.  Vitagliano  C.  Raschi  A.  Minnocci  A. 《Photosynthetica》2001,39(3):403-410
Five-year-old plants of two olive cultivars (Frantoio and Moraiolo) grown in large pots were exposed for 7 to 8 months to ambient (AC) or elevated (EC) CO2 concentration in a free-air CO2 enrichment (FACE) facility. Exposure to EC enhanced net photosynthetic rate (P N) and decreased stomatal conductance, leading to greater instantaneous transpiration efficiency. Stomata density also decreased under EC, while the ratio of intercellular (C i) to atmospheric CO2 concentration and chlorophyll content did not differ, except for the cv. Moraiolo after seven months of exposure to EC. Analysis of the relationship between photosynthesis and C i indicated no significant change in carboxylation efficiency of ribulose-1,5-bisphosphate carboxylase/oxygenase after five months of exposure to EC. Based on estimates derived from the P N-C i relationship, there were no apparent treatment differences in daytime respiration, CO2 compensation concentration, CO2-saturated photosynthetic rate, or photosynthetic rate at the mean C i, but there was a reduction in stomata limitation to P N at EC. Thus 5-year-old olive trees did not exhibit down regulation of leaf-level photosynthesis in their response to EC, though some indication of adjustment was evident for the cv. Frantoio with respect to the cv. Moraiolo.  相似文献   

14.
BACKGROUND AND AIMS: The inverse relationship between the number of stomata and atmospheric CO2 levels observed in different plant species is increasingly used for reconstructions of past CO2 concentrations. To validate this relationship, the potential influence of other environmental conditions and ontogenetical development stage on stomatal densities must be investigated as well. Quantitative data on the changes in stomatal density of conifers in relation to leaf development is reported. METHODS: Stomatal frequency and epidermal cells of Tsuga heterophylla needles during different stages of budburst were measured using computerized image analysis systems on light microscope slides. KEY RESULTS: Stomata first appear in the apical region and subsequently spread basipetally towards the needle base during development. The number of stomatal rows on a needle does not change during ontogeny, but stomatal density decreases nonlinearly with increasing needle area, until about 50 % of the final needle area. The total number of stomata on the needle increases during the entire developmental period, indicating that stomatal and epidermal cell formation continues until the needle has matured completely. CONCLUSIONS: Epidermal characteristics in developing conifer needles appear to be fundamentally different from angiosperm dicot leaves, where in general leaf expansion in the final stages is due to cell expansion rather than cell formation. The lack of further change in either stomatal density or stomatal density per millimetre needle length (the stomatal characteristic most sensitive to CO2 in conifers) in the final stages of leaf growth indicates that in conifers the stage of leaf maturation would not influence CO2 reconstructions based on stomatal density.  相似文献   

15.
16.
An empirical model for stomatal conductance (g), proposed by Leuning (1995, this issue) as a modification of Ball, Woodrow & Berry's (1987) model, is interpreted in terms of a simple, steady-state model of guard cell function. In this model, stomatal aperture is a function of the relative turgor between guard cells and epidermal cells. The correlation between g and leaf surface vapour pressure deficit in Leuning's model is interpreted in terms of stomatal sensing of the transpiration rate, via changes in the gradient of total water potential between guard cells and epidermal cells. The correlation between g, CO2 assimilation rate and leaf surface CO2 concentration in Leuning's model is interpreted as a relationship between the corresponding osmotic gradient, irradiance, temperature, intercellular CO2 concentration and stomatal aperture itself. The explicit relationship between osmotic gradient and stomatal aperture (possibly describing the effect of changes in guard cell volume on the membrane permeability for ion transport) results in a decrease in the transpiration rate in sufficiently dry air. Possible extension of the guard cell model to include stomatal responses to soil water status is discussed.  相似文献   

17.
  • Stomata modulate the exchange of water and CO2 between plant and atmosphere. Although stomatal density is known to affect CO2 diffusion into the leaf and thus photosynthetic rate, the effect of stomatal density and patterning on CO2 assimilation is not fully understood.
  • We used wild types Col‐0 and C24 and stomatal mutants sdd1‐1 and tmm1 of Arabidopsis thaliana, differing in stomatal density and pattern, to study the effects of these variations on both stomatal and mesophyll conductance and CO2 assimilation rate. Anatomical parameters of stomata, leaf temperature and carbon isotope discrimination were also assessed.
  • Our results indicate that increased stomatal density enhanced stomatal conductance in sdd1‐1 plants, with no effect on photosynthesis, due to both unchanged photosynthetic capacity and decreased mesophyll conductance. Clustering (abnormal patterning formed by clusters of two or more stomata) and a highly unequal distribution of stomata between the adaxial and abaxial leaf sides in tmm1 mutants also had no effect on photosynthesis.
  • Except at very high stomatal densities, stomatal conductance and water loss were proportional to stomatal density. Stomatal formation in clusters reduced stomatal dynamics and their operational range as well as the efficiency of CO2 transport.
  相似文献   

18.
Image analysis was used in studying stomatal morphology during acclimatization of tobacco plantlets to ex vitro conditions, 45 d after transfer leaf area was 15 times, and total number of stomata per leaf four times increased. During acclimatization stomatal density was decreased considerably on both leaf sides, and was compensated by an increase in stomatal sizes, e.g., in stomatal length and in stomatal area (both guard cells and pore). Elongation of stomata was increased indicating that the originally circular stomata of in vitro plantlets were changed into elliptical ones in ex vitro acclimatized plants. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

19.
气孔是植物与外界环境进行水分和气体交换的主要通道,调节植物碳同化和水分散失的平衡关系,在一定程度上反映植物对外界环境变化的适应。沿太白山北坡1100—2300 m海拔,测定4种栎属树种的气孔性状,分析气孔性状沿海拔的变化规律和其对环境因子的响应。结果表明:(1)气孔密度与气孔长度间的负相关在4个树种间均显著存在(P0.05);除栓皮栎(Quercus variabilis)外,气孔密度与潜在气孔导度指数的正相关关系均达显著水平;而气孔宽度与气孔长度之间只在栓皮栎和锐齿栎(Q. aliena var. acuteserrata)达到显著水平。(2)栓皮栎和槲栎(Q. aliena)的气孔长度和宽度随海拔升高而下降,气孔密度、潜在气孔导度指数增加,辽东栎(Q. wutaishansea)变化形式则相反;锐齿栎气孔宽度减小,其余性状沿海拔呈单峰变化,在约1600 m处气孔长度达到最小值,气孔密度和潜在气孔导度指数达到最大值。(3)与土壤因子相比,气孔性状主要受气候因素的影响。潜在气孔导度指数与大气温度、空气湿度成极显著正相关(P0.01),与降水量显著负相关(P0.05)。其中,空气相对湿度是影响潜在气孔导度指数的主要因素,能够解释气孔变异的22.9%。本研究结果对于深入认识秦岭太白山地区栎属树种对环境变化的响应和适应提供理论证据。  相似文献   

20.
植物气孔运动调节的新进展   总被引:1,自引:0,他引:1  
综述了植物气孔的发生和气孔运动的调节机制,并对高表达pepc水稻气孔调节机理和高光效特性的关系作了简要的分析,最后对植物气孔运动的调节机制研究做了展望。  相似文献   

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