CURSO DIÁRIO DAS TROCAS GASOSAS EM PLANTAS DE FEIJÃO-CAUPI SUBMETIDAS A DEFICIÊNCIA HÍDRICA

Abstract

This work had the objective of checking the echophysiological behavior of cowpea [Vigna unguiculata (L.) Walp.] cv. BRS Xique-xique cultivated under different levels of hydric deficit. The plants were cultivated in vases with capacity for 10L, containing one substratum composed by: 88,45% sand, 3,71% of clay, 7,84 % of silte. The experimental design was entirely randomized with three treatments (TO- reposition of 100% of lost water by evapotranspiration, T1- reposition of 50% and T2- reposition of 25%) and five repelicates. Previously, T1 and T2 suffered a period of stress and were later rehydrated. In the day of the assessment, the plants of T1 had been undergone to stress for three days, while the plants T2 for 5 days. The variables analyzed were: leaf water potential, net photosynthesis, stomatal conductance, transpiration, internal CO2 concentration and foliar temperature. The fewest availability of water caused reductions in the net photosynthesis rates, stomatal conductance and transpiration in T1 and T2 when they were compared to T0. The internal CO2 concentration in T2 was the greater among analyzed treatments. The reposition of 50 % of the lost water hasn´t caused any damage in the net photosynthesis.