Limitations to leaf photosynthesis in field-grown grapevine under drought - metabolic and modelling approaches
Limitations to leaf photosynthesis in field-grown grapevine under drought - metabolic and modelling approaches
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DOI：
10.1071/pp01040
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发表时间：
2002-01-01
影响因子：
3
通讯作者：
Chaves, MM
中科院分区：
文献类型：
--
作者：
Maroco, JP;Rodrigues, ML;Chaves, MM
研究了缓慢干旱胁迫对葡萄属欧亚种葡萄气体交换、叶绿素a荧光及生理生化指标的影响。叶（CV. Aragonez，syn.丹魄）生长在商业葡萄园（葡萄牙南部）进行了评估。相对于充分浇水的植物（黎明前水势，Psi（PD）= -0.13+/-0.01 MPa），干旱胁迫的植物（Psi（PD）= -0.97+/-0.01 MPa）具有较低的光合速率（约70%）、气孔导度和PSII活性（与较高的醌A库减少和较低的PSII开放中心效率相关）。气孔限制光合作用增加干旱胁迫植物相对于良好浇水植物约44%。模拟的净光合作用的内部CO2的反应表明，干旱胁迫的植物有显着减少最大Rubisco羧化活性（约32%），核酮糖-1，5-二磷酸再生（约27%），磷酸丙糖（丙糖-P）的利用率（约37%）相对于良好浇水的植物。干旱对模拟的生化参数的影响之间有很好的协议，并在碳代谢的关键酶，即Rubisco，甘油醛-3-磷酸脱氢酶，核酮糖-5-磷酸激酶和果糖-1，6-二磷酸酶的体外活性。量子产率测量下的环境（35帕）和饱和CO2（100帕）干旱胁迫的植物相对于浇水良好的植物，以及在光和CO2饱和条件下（三倍环境CO2水平）测量的最大光合速率下降。虽然气孔关闭是一个强大的限制，在干旱条件下的CO2同化，电子传递，CO2羧化，利用丙糖-P的能力也比较减少适应的光合机械脱水，缓慢发展在田间条件下。在这项研究中提出的结果证实，建模光合反应的气体交换数据的基础上，可以成功地用于预测光合作用的代谢限制。
The effects of a slowly-imposed drought stress on gas-exchange, chlorophyll a fluorescence, biochemical and physiological parameters of Vitis vinifera L. leaves (cv. Aragonez, syn. Tempranillo) growing in a commercial vineyard (South Portugal) were evaluated. Relative to well-watered plants (predawn water potential, Psi(PD) = -0.13+/-0.01 MPa), drought-stressed plants (Psi(PD) = -0.97+/-0.01 MPa) had lower photosynthetic rates (ca 70%), stomatal conductance, and PSII activity (associated with a higher reduction of the quinone A pool and lower efficiency of PSII open centres). Stomatal limitation to photosynthesis was increased in drought-stressed plants relative to well-watered plants by ca 44%. Modelled responses of net photosynthesis to internal CO2 indicated that drought-stressed plants had significant reductions in maximum Rubisco carboxylation activity (ca 32%), ribulose-1,5-bisphosphate regeneration (ca 27%), and triose phosphate (triose-P) utilization rates (ca 37%) relative to well-watered plants. There was good agreement between the effects of drought on modelled biochemical parameters, and in vitro activities of key enzymes of carbon metabolism, namely Rubisco, glyceraldehyde-3-phosphate dehydrogenase, ribulose-5-phosphate kinase and fructose-1,6-bisphosphate phosphatase. Quantum yields measured under both ambient (35 Pa) and saturating CO2 (100 Pa) for drought-stressed plants were decreased relative to well-watered plants, as well as maximum photosynthetic rates measured at light and CO2 saturating conditions (three times ambient CO2 levels). Although stomatal closure was a strong limitation to CO2 assimilation under drought, comparable reductions in electron transport, CO2 carboxylation, and utilization of triose-P capacities were also adaptations of the photosynthetic machinery to dehydration that slowly developed under field conditions. Results presented in this study confirm that modelling photosynthetic responses based on gas-exchange data can be successfully used to predict metabolic limitations to photosynthesis.