Changes in endogenous abscisic acid and stomata of the resurrection fern, Pleopeltis polypodioides, in response to de‐ and rehydration

Abstract

AbstractPremiseWhile 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 (H2O2), nitric oxide (NO), and Ca2+, low and high light intensities, and blue light (BL) on stomatal opening of Pleopeltis polypodioides.MethodsEndogenous ABA was quantified using gas chromatography‐mass spectrometry; microscopy results and stomatal responses to light and chemical treatments were analyzed with Image J.ResultsThe 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 Ca2+, regardless of ABA, H2O2 effect was weak.ConclusionsThe 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.