John Susan P, Svihla Zachary T, Hasenstein Karl H
Department of Biology, University of Louisiana at Lafayette, Lafayette, LA, 70503, USA.
Am J Bot. 2023 Apr;110(4):e16152. doi: 10.1002/ajb2.16152. Epub 2023 Apr 13.
While angiosperms respond uniformly to abscisic acid (ABA) by stomatal closure, the response of ferns to ABA is ambiguous. We evaluated the effect of endogenous ABA, hydrogen peroxide (H O ), nitric oxide (NO), and Ca , low and high light intensities, and blue light (BL) on stomatal opening of Pleopeltis polypodioides.
Endogenous ABA was quantified using gas chromatography-mass spectrometry; microscopy results and stomatal responses to light and chemical treatments were analyzed with Image J.
The ABA content increases during initial dehydration, peaks at 15 h and then decreases to one fourth of the ABA content of hydrated fronds. Following rehydration, ABA content increases within 24 h to the level of hydrated tissue. The stomatal aperture opens under BL and remains open even in the presence of ABA. Closure was strongly affected by BL, NO, and Ca , regardless of ABA, H O effect was weak.
The decrease in the ABA content during extended dehydration and insensitivity of the stomata to ABA suggests that the drought tolerance mechanism of Pleopeltis polypodioides is independent of ABA.
被子植物通过气孔关闭对脱落酸（ABA）做出一致反应，而蕨类植物对ABA的反应尚不明确。我们评估了内源性ABA、过氧化氢（H₂O₂）、一氧化氮（NO）和钙离子、低光和高光强度以及蓝光（BL）对多足蕨气孔开放的影响。
使用气相色谱 - 质谱法定量内源性ABA；用Image J分析显微镜结果以及气孔对光和化学处理的反应。
在初始脱水过程中ABA含量增加，在15小时达到峰值，然后降至水合叶片ABA含量的四分之一。复水后，ABA含量在24小时内增加到水合组织的水平。气孔在蓝光下开放，即使存在ABA也保持开放。关闭受到蓝光、NO和钙离子的强烈影响，无论ABA如何，H₂O₂的影响较弱。
长时间脱水过程中ABA含量的降低以及气孔对ABA的不敏感性表明，多足蕨的耐旱机制独立于ABA。
