ibclogo XVI International Botanical Congess


Abstract Number: 5106
Poster No. = 1410


PHOTOSYNTHESIS AND WATER RELATION ON THIRTY WOODY SPECIES OF CERRADO VEGETATION


C.H.B.A. Prado* and Z. Wenhui, Dep. of Botany, Federal University of São Carlos, São Carlos, SP, Brasil, 13565-905


In spite of vast Cerrado's floristic diversity just 6 adult woody species were study in relation to carbon and water balance. In order to know which kind of compromise exists between carbon and water economy under field conditions we measured on thirty Cerrado's adult woody species during wet and dry seasons: gas exchange, leaf water potential (_l), osmotic potential (_) and pre-dawn leaf water potential (_pd). The same mean values of water use efficiency (WUE) in the morning were holding during dry and wet seasons because the rates of transpiration and net photosynthesis decreased 30% on average bases (P<0.001) during dry season. Mean values of _l in the morning, _ and _pd during dry and wet season were not significantly different. It was clear that gas exchange adjustments and effective recuperation of water balance during the night were responsible for preserving carbon gain, WUE and high values of leaf water potential in the morning during dry season.


HTML-Version made 7. July 1999 by Kurt Stüber