Respostas fisiológicas do ipê-roxo (handroanthus impetiginosus (Mart. ex DC) Mattos) ao estresse hídrico.

Abstract

Water stress can affect plants in several aspects, promoting reduction in stomatal conductance and photosynthesis, resulting severe alterations in growth, development and chemical composition, which can lead them to death. This study aimed to analyze the stomatal behavior of young plants of Handroanthus impetiginosus under progressive water stress, and how they behave after rehydration. Plants with 12 months of age were subjected to two treatments: irrigated and water stress imposed by withholding water. It was daily evaluated the relative water content, stomatal conductance, transpiration rate, intercellular CO2 concentration, and photosynthetic rates. After ten days remained under this stress condition, irrigation was restored, and recovery was evaluated. Drought stress decreased rapidly and progressively the relative water content, stomatal conductance, transpiration, carboxylation efficiency and photosynthesis of plants. It was observed increase in intercellular CO2 concentration with increase of water stress. After the resumption of water supply, the plants showed recovery in these physiological processes. Water stress did not affect the water efficiency use of plants.