Ecophysiology of water stressed Handroanthus impetiginosus (Mart. Ex. DC) Mattos) Seedlings

The objective of this work was to evaluate the ecophysiological behavior of Handroanthus impetiginosus seedlings in response to water stress and rehydration. For this, an experiment was conducted, in which irrigation was suppressed for twelve days, up to the beginning of leaves fall, followed by irrigation resumption. The variables measured were photosynthesis, stomatal conductance, transpiration, instantaneous and intrinsic water use efficiency and leaf water potential. The evaluations were made during the irrigation suspension time and after resumption, until the photosynthesis values from water stressed plants equaled those which did not suffer water shortage. Water stress affected photosynthesis, transpiration and stomatal conductance, with diminution of its levels, and fast recovery after rehydration. The water use efficiency was higher with water stress. H. impetiginosus has the capability of reducing its water potential under stress, and has a fast recovery of photosynthetic rates after the end of the stress.