Transpira o e condutancia foliar 角 difus o de vapor de feijoeiro irrigado em fun o da temperatura da folhagem e vari芍veis ambientais = Transpiration and stomatal conductance of irrigated bean in relation to foliage temperature and environmental variables

作者：Felipe Gustavo Pilau; Reinaldo Antnio Garcia Bonnecarrere; Durval Dourado Neto; Antnio Luiz Fancelli

来源：Acta Scientiarum - Agronomy, 2007.

• est mato
• temperatura do ar
• deficit de satura o de vapor do ar
• radia o fotossinteticamente ativa
• Phaseolus vulgaris
• stomatal
• air temperature
• vapor pressure deficit
• photosynthetic active radiation
• Phaseolus vulgaris

芍reas com cultivo irrigado t那m o d谷ficit de satura o de vapor (DPV) etemperatura do ar modificados. Sendo a resposta estom芍tica influenciada por essas vari芍veis e outras como temperatura do dossel, a cultura do feij o irrigado tende a apresentar condutancia estom芍tica 角 difus o de vapor (Gva) e transpira o, diferenciados com rela o ao cultivo de sequeiro. Avaliando-se Gva e transpira o com por metros de equil赤brio dinamico, verificou-se que a taxa de transpira o apresentou melhor correla o em rela o 角 temperatura da folhagem em condi es de folhas ao sol, do que em rela o a folhassombreadas. Rela es de Gva com temperatura do ar, DPV e radia o fotossinteticamente ativa (PAR) refor am a intera o dos fatores ambientais com a resposta estom芍tica. Valores de Gva apresentaram correla o exponencial negativa tanto com temperatura do ar e DPV,para valores entre 20 e 35～C, de 0,5 角 3 KPa, respectivamente e aumento exponencial quando relacionada a PAR, mesmo com valores superiores a 2000 mmol m-2 s-1. 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 irrigatedcommon 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 mmol m-2 s-1.