ECOPHYSIOLOGY OF THE TREE SPECIES Cedrela fissilis Vell. (Meliaceae) SUBMITTED TO FLOODING

Abstract

Soil water saturation requires different kinds of adaptative strategies from tree species which live within such conditions. Aiming at providing information around  the responses for flooding tolerance of a greater number of tree species and for the purpose of  sheltering prejects developed for recovering degraded areas subjected to flooding, the present work performed a ecophysiological evaluation of  Cedrela fissilis under water saturation conditions of the substrate, including anatomical studies of gas exchange, antioxidant system and growth. In order to perform it, plants aging around 100 days were subjected to three treatments: Control (FC) where the substrate was at field capacity; Flooded Root (FR), where the substrate remained submerged, however without accumulating water line on its  surface and  Flooded Stem (FS), in which there  was water accumulation of around 3.0 cm over the substrate, flooding part of their stems. The plants were kept under such conditions for 90 days. No plant died during the experiment. This absolute number of survivors might be justified, mainly, by the development of cortical intercellular spaces found on flooded plants. Gas exchanges were limited. The periderm was reduced. There was accumulation of  starch granules on stem tissues and significant lipid peroxidation on leaves. SOD activity was decreased but APX and CAT activities on foliar tissues were increased. It is possible to state that young Cedrela fissilis plants partially tolerate flooding since they develop physiological, anatomical and biochemical changes which allow them to survive, although their growth and photosynthetic efficiency are restricted.