INRA, UMR Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, Montpellier, France.
Plant Cell Environ. 2010 Apr;33(4):636-47. doi: 10.1111/j.1365-3040.2009.02091.x. Epub 2009 Nov 25.
Abscisic acid (ABA) affects plant metabolism and water transfers via multiple mechanisms at cell, organ and whole plant levels. These mechanisms translate into contradictory effects on leaf growth, so the literature reports positive, null or negative effects of ABA on leaf growth upon water deficit. We review evidences based on genetic manipulations of ABA biosynthesis, feeding the plant with artificial ABA or partial root drying and provide elements to avoid confusions of effects. We propose that ABA has mainly three effects on growth. (i) Via its controlling effect on stomatal aperture and transpiration rate, an increased concentration of ABA tends to buffer the day-night alternations of leaf growth rate and the negative effect of evaporative demand. (ii) ABA tends to improve leaf growth via an increase in the conductance to water transfer in the plant as a result of increased tissue hydraulic conductivity. (iii) ABA has also a modest non-hydraulic effect which is negative in plants subjected to water deficit, either manipulated for ABA synthesis or fed with artificial ABA, but can be positive in well watered plants deficient of ABA. The overall effect of increasing ABA biosynthesis depends on the relative weight of each of these effects under different environmental scenarios.
脱落酸（ABA）通过细胞、器官和整株植物水平的多种机制影响植物代谢和水分转移。这些机制转化为对叶片生长的矛盾影响，因此文献报道 ABA 在水分亏缺下对叶片生长有正向、零向或负向的影响。我们综述了基于 ABA 生物合成的遗传操作、向植物饲喂人工 ABA 或部分根干燥的证据，并提供了避免混淆影响的要素。我们提出 ABA 对生长主要有三种影响。（i）通过控制气孔开度和蒸腾速率，ABA 浓度的增加倾向于缓冲叶片生长速率的昼夜交替和蒸发需求的负向影响。（ii）ABA 倾向于通过增加组织水力传导度来增加植物的水分传输导度，从而促进叶片生长。（iii）ABA 还具有适度的非水力效应，在ABA 合成受到人为操纵或用人工 ABA 喂养的水分亏缺植物中为负向，但在水分充足且缺乏 ABA 的植物中可以为正向。增加 ABA 生物合成的整体效应取决于在不同环境场景下这些效应的相对权重。
