FB Biologie der Universität, Postfach 3049, D-6750, Kaiserslautern, FRG.
Photosynth Res. 1988 Nov;18(3):327-36. doi: 10.1007/BF00034837.
Gas exchange and abscisic acid content of Digitalis lanata EHRH. have been examined at different levels of plant water stress. Net photosynthesis, transpiration and conductance of attached leaves declined rapidly at first, then more slowly following the withholding of irrigation. The intercellular partial pressure of CO2 decreased slightly. The concentration of 2-cis(S)ABA increased about eight-fold in the leaves of non-irrigated plants as compared with well-watered controls. A close linear correlation was found between the ABA content of the leaves and their conductance on a leaf area basis. In contrast, the plot of net assimilation versus ABA concentration was curvilinear, leading to an increased efficiency of water use during stress. After rewatering, photosynthesis reached control values earlier than transpiration, leaf conductance and ABA content. From these data it is concluded that transpiration through the stomata is directly controlled by the ABA content, whereas net photosynthesis is influenced additionally by other factors.Possible reasons for the responses of photosynthesis and water use efficiency to different stress and ABA levels are discussed.
对不同程度水分胁迫下的毛地黄叶片的气体交换和脱落酸含量进行了研究。在停止灌溉后，附着叶片的净光合作用、蒸腾作用和传导率最初迅速下降，然后下降速度较慢。胞间 CO2 分压略有下降。与充分浇水的对照相比，未浇水植物叶片中的 2-顺（S）ABA 浓度增加了约 8 倍。叶片 ABA 含量与其叶面积基础上的传导率之间存在密切的线性相关性。相比之下，净同化作用与 ABA 浓度的关系是曲线关系，导致胁迫期间用水效率增加。重新浇水后，光合作用比蒸腾作用、叶片传导率和 ABA 含量更早达到对照值。从这些数据可以得出结论，通过气孔的蒸腾作用直接受 ABA 含量的控制，而净光合作用还受到其他因素的影响。讨论了光合作用和水分利用效率对不同胁迫和 ABA 水平的反应的可能原因。
