Scaling up of leaf transpiration ans stomatal cinductance of two Eucalyptus grandis x Eucalyptus urophylla clone in response to environmental variables

This study aimed at characterizing leaf ecophysiological behavior of two clones of Eucalyptus sp related to environmental variables such as photosynthetically active radiation (Qleaf) and vapor pressure deficit of the atmosphere (VPD) at two scales (pot and plot), as well as promoting a change of information obtained from a smaller scale to a higher one. The study was conducted at UNICAMP, Sao Paulo, Brazil. For data transpiration (E) and stomata conductance (Gs) porometry an infrared gas analyzer was used. Local environmental variables associated with Qleaf and VPD were recorded by the automatic station of CEPAGRI/UNICAMP installed at the study site. At all scales, individuals were under the same range of predawn leaf water potential (0 to -0.5 MPa). The scaling of information was performed by applying the ecophysiological model, to simulate the E and Gs as a function of Qleaf and VPD. The exchange of E and Gs were consistently above the plot scale when compared to the pot scale for the two clones under study. The proposed models were effective in the extrapolation of E and Gs between different scales, but the best results were obtained in the relations E, Gs and Qleaf.399025326

Environmental variables effects in ecophysiological behavior of two clones of Eucalyptus grandis x Eucalyptus urophylla: field conditions

This study aimed at characterizing the behavior of two commercial clones of Eucalyptus grandis x Eucalyptus urophylla with photosynthetic active radiation (Qleaf), atmospheric vapor pressure deficit (VPD) and predawn leaf water potential (Psi(pd)). The study was conducted in an experimental plot of the Faculty of Agricultural Engineering, State University of Campinas (FEAGRI / UNICAMP), located in Campinas, Sao Paulo, Brazil. The clones were of the same age (240 days) and at the same site of planting. Measurements of transpiration (E), stomata conductance (Gs) and photosynthesis (A) were carried out from January to July 2008 with the help of a porometer and Psi(pd) measurements were performed with the aid of a Scholander pressure chamber. Differences were observed in the responses of clones to environmental variables as well as in water use efficiency (WUE). The information gained may be used for better adjustment of forest management plans according to the ecophysiological specificity of each clone, for hydrological aspects of a watershed.399241943