Transpiration and stomatal conductance of irrigated bean in relation to foliage temperature and environmental variables - DOI: 10.4025/actasciagron.v29i1.76

Abstract

Irrigated areas present environmental variables such as vapor pressure deficit (DPV) and modified air temperature. The stomatal response is not only affected by these modified environmental conditions, but also by others such as canopy temperature. Thus, an irrigated bean crop tend to present modifications in stomatal conductance (Gva) and transpiration in relation to a non irrigated common bean crop. Gva and transpiration were measured with steady-state null-balance porometers. Results showed that transpiration rate correlated better with canopy temperature in conditions of sunny leaves than of shaded leaves. The relation between Gva and air temperature, and between DPV and photosynthetic active radiation (PAR) reinforce the interaction of the environmental variables with stomatal response. Gva values presented negative exponential correlation with air temperature and DPV, for values between 20 and 35°C, and 0.5 to 3 KPa, respectively, and an exponential increase when correlated with PAR, even when valuer were above 2000 µmol m^-2 s^-1