Arve Louise E, Torre Sissel
Norwegian University of Life Sciences, Department of Plant Sciences, PO Box 5003, 1432 Ås, Norway.
Funct Plant Biol. 2015 Apr;42(4):376-386. doi: 10.1071/FP14247.
High relative air humidity (RH) promotes stomatal opening in tomato leaves. This study examined the role of the plant hormones abscisic acid (ABA) and ethylene in high RH induced stomatal opening. Plants were grown in high (90%) and moderate (60%) RH or transferred from moderate to high RH. ABA levels were only slightly, but significantly decreased during darkness by increasing RH. However, a significantly higher ethylene evolution was found in high RH compared with moderate RH. Ethephon increased conductance and stomatal aperture in moderate RH. Treatment with amino-ethoxyvinylglycine (AVG) suppressed stomatal opening when plants were transferred from moderate to high RH. Similarly, blocking the ethylene receptor or using an ethylene-insensitive mutant (NR) reduced the response to high RH. These results demonstrate that both ethylene production and sensitivity play a role in high RH-induced stomatal opening in tomato leaves. The increased conductance found when plants were transferred to high RH could be counteracted by exogenous ABA spray. The ABA deficient mutant 'Flacca' produced high levels of ethylene irrespective of the RH and the difference in water loss and conductance between high and moderate grown 'Flacca' plants was attenuated compared with WT. The results indicate that both ABA and ethylene play a role in air humidity control of stomatal movement in tomato.
较高的相对空气湿度（RH）可促进番茄叶片气孔开放。本研究探讨了植物激素脱落酸（ABA）和乙烯在高湿度诱导气孔开放中的作用。将植株种植于高湿度（90%）和中等湿度（60%）环境中，或从中等湿度转移至高湿度环境。黑暗条件下，随着湿度增加，ABA水平仅略有下降，但降幅显著。然而，与中等湿度相比，高湿度条件下乙烯释放量显著更高。乙烯利可增加中等湿度条件下的气孔导度和气孔孔径。当植株从中等湿度转移至高湿度时，用氨基乙氧基乙烯基甘氨酸（AVG）处理可抑制气孔开放。同样，阻断乙烯受体或使用乙烯不敏感突变体（NR）可降低对高湿度的响应。这些结果表明，乙烯的产生和敏感性在高湿度诱导的番茄叶片气孔开放中均起作用。当植株转移至高湿度环境时，外源喷施ABA可抵消气孔导度的增加。ABA缺陷突变体“Flacca”无论湿度如何均产生高水平乙烯，与野生型相比，高湿度和中等湿度条件下生长的“Flacca”植株在水分损失和气孔导度上的差异减弱。结果表明，ABA和乙烯在番茄气孔运动的空气湿度调控中均起作用。
