Root signals and stomatal closure in relation to photosynthesis, chlorophyll a fluorescence and adventitious rooting of flooded tomato plants

Abstract

Stomata of flooded plants did not close in response to short-lived decreases in psi(L) or to increased C(i) resulting from impaired PSII photochemistry. Instead, stomatal closure depressed C(i) and this in turn largely explained subsequent changes in chlorophyll fluorescence parameters. Stomatal opening was promoted by the presence of well-aerated adventitious roots, implying that loss of function of root signalling contributes to closing of stomata during flooding. The possibility that this involves inhibition of cytokinin or gibberellin export was not well supported.