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干旱胁迫对杨树光合生理指标的影响

付士磊1,2;周永斌3;何兴元1;陈玮1   

  1. 1中国科学院沈阳应用生态研究所, 沈阳 110016;2中国科学院研究生院, 北京100039;3沈阳农业大学林学院, 沈阳 110161
  • 收稿日期:2005-12-23 修回日期:2006-08-24 出版日期:2006-11-18 发布日期:2006-11-18

Effects of drought stress on photosynthesis physiology of Populus pseudo-simonii

FU Shilei1,2; ZHOU Yongbin3; HE Xingyuan1; CHEN Wei1   

  1. 1Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; 2Graduate University of Chinese Academy of Sciences, Beijing 100039, China; 3College of Forestry, Shenyang Agricultural University, Shenyang 110161, China
  • Received:2005-12-23 Revised:2006-08-24 Online:2006-11-18 Published:2006-11-18

摘要: 采用PEG模拟干旱胁迫的方法,利用气体交换法和叶绿素荧光技术,研究了干旱胁迫下小青杨(Populus pseudo-simonii)的光合生理变化.结果表明,干旱胁迫初期,小青杨的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(gs)和胞间CO2浓度(Ci)值均随干旱胁迫增强而下降,杨树Pn的下降主要是由于gs下降引起的;干旱胁迫后期,Ci值逐渐升高,非气孔限制成为光合作用的主要限制因子.干旱胁迫后期,PSⅡ原初光能转化效率(Fv/Fm)和PSⅡ潜在活性(Fv/Fo)明显下降,光抑制增强,光合电子传递受阻.POD酶的活性在胁迫初期升高,后期降低,说明干旱胁迫初期对保护系统酶活性升高有诱导作用,随着胁迫时间的延长,Fv/FmFv/Fo降低,活性氧清除酶活性下降,活性氧代谢的平衡被打破,导致光合器官的伤害.由此表明,干旱胁迫后期Pn的降低与PSⅡ荧光参数及POD酶活性下降有关.

关键词: 根系还原力, 混作, 5种禾本科作物, 根系分泌物, 质外体铁

Abstract: In this paper, the effects of drought stress simulated by PEG on the photosynthesis of Populus pseudo-simonii were monitored by gas exchange and chlorophyll fluorescence techniques. The results showed that in the early phase of drought stress, net photosynthetic rate (Pn), transpiration rate (Tr), stomata conductance (gs),and intercellular CO2 concentration (Ci) decreased with increasing stress, and the decrease of Pn was mainly related to the decreased gs. In the late phase, Ci increased gradually, while Fv/Fm and Fv/Fo decreased significantly. POD activity increased in the early phase, but decreased in the late phase. All of these indicated that in the early phase of drought stress, stomata closure was the main factor limiting P. pseudo-simonii photosynthesis, while in the late phase, the main limiting factor was non-stomatal.A short period of drought stress to the stress resulted in the decrease of PS Ⅱ efficiency and POD activity.

Key words: Mixed cropping, Gramineous plants, Root exudates, Apoplast Fe, Root Fe(Ⅲ) reducing capacity