Chlorophyll fluorescence varies more across seasons than leaf water potential in drought-prone plants

Abstract

ABSTRAC TAmong the effects of environmental change, the intensifi cation of drought events is noteworthy, and tropical vegetation is predicted to be highly vulnerable to it. However, it is not clear how tropical plants in drought-prone habitats will respond to this change. In a coastal sandy plain environment, we evaluated the response of six plant species to water defi cits across seasons, the relationship between their morphophysiological traits, and which traits would be the best descriptors of plants' response to drought. Regardless of leaf succulence and phenology, responses between seasons were most strongly related to chlorophyll fl uorescence. In this study we have demonstrated that a better comprehension of how tropical species from drought-prone habitats cope with changes in water availability can be based on seasonal variation in leaf water potential and chlorophyll fl uorescence. Temporal variation in leaf water potential and chlorophyll fl uorescence was found useful for differentiating between groups of sandy soil species that are responsive or unresponsive to water availability. However, chlorophyll fl uorescence appeared to be a more sensitive descriptor of their seasonal and short-term responses.

How the long-life span leaves of Ouratea castaneifolia Engl. (Ochnaceae) differ in distinct light conditions

“…A reduction in potential quantum yield (Fv/Fm) was observed for the plants of the forest edge at noon. A reduction in these values at noon has been documented for several species when exposed to high radiation (Ribeiro et al 2004;Shimizu et al 2006;Franco et al 2007;Favaretto et al 2011;Rosado and Mattos 2016;Kuster et al 2017). Values of Fv/Fm below 0.8 indicate the occurrence of photoinhibition (Björkman and Demmig 1987); however, this photoinhibition in the long-life span leaves of O. castaneifolia may be reversible, since predawn values are higher than those observed at noon, indicating a partial recovery of Photosystem II (PSII).…”

Fatores determinantes dos padrões de similaridade, distribuição e abundância de árvores em dois ambientes da Mata Atlântica

“…Isso sugere que, ou a estruturação das comunidades nesse ambiente podem ser governadas por processos neutros, ou que outros atributos não avaliados nesse estudo (p.ex. potencial hídrico e fluorescência da clorofila (Rosado & Mattos, 2016)) poderiam refletir melhor as maiores ou menores abundâncias e distribuições das espécies nesses ambientes recentes e restritivos. Por outro lado, no ambiente AMR as espécies com maiores frequências (tanto abundantes quanto escassas) apresentaram maiores valores de potencial de dispersão, indicando que esse atributo pode favorecer uma distribuição mais ampla nesse ambiente .…”