Physiological responses to flooding in tropical tolerant trees

Abstract

Herrera, A., Rengifo, E., Tezara, W. (2009). Physiological responses to flooding in tropical tolerant trees. Ecosistemas 19(1):37-51.

Flooding  of  plants  inhibits  water  absorption,  causes  stomatal  closure  and  reduces  photosynthetic  rate  (A).  In  tolerant  species  these physiological  responses  are  reverted  with  time.  In  a  seasonally  flooded  forest,  we  proposed  to  validate  a  model  to  explain  the  initial responses  and  the  acclimation  to  flooding.  Stomatal  closure  was  apparently  produced  by  an  increase  in  xilematic  and  leaf  content  of abscisic acid (ABA). The reduction in stomatal conductance (gs) was accompanied by a diminution in A, diminution in the relative stomatal limitation to photosynthesis (Ls) and increase in the relative mesophyll limitation (Lm). At maximum flood A and gs returned to the values of drained plants. Although a reduction in intercellular [CO2] (Ci) caused by the diminution of A may cause chronic photoinhibition, no decrease in the quantum yield of PSII (Fv/Fm) was observed. Increases of Lm with diminution of Ls suggest that stomatal closure was not the main cause of the reduction of A, which was accompanied by a diminution of soluble protein content, an indirect measure of rubisco content. At maximum flooding, all variables that had suffered changes during rising-waters returned to values of drained trees, indicating acclimation.