Efeito do déficit hídrico sobre o metabolismo do nitrogênio e o crescimento de quatro cultivares de feijão (Paseolus vulgaris L)

Abstract

A simple and sensitive method for the isolation and estimation of free proline in the presence of various interferent amino acids and the changes in the content of free proline, total free amino acids and proteins in dehydrated leaf discs and intact plants of four bean (Phaseolus vulgaris L.) cultivars are discussed. The cultivar ‘Manteigao Fosco 11’ accumulated the most proline in leaf discs when subjected to desiccation, followed by the ‘Rico 23’, ‘Mulatinho’ and ‘Carioca’. Leaf discs of the four cultivars showed a similar pattern of accumulation of total free amino acids and proteins soluble in phosphate buffer, pH 7,0, under severe dehydration. When intact plants were subjected to water stress by withholding water, free proline, total free amino acids, and soluble and insoluble proteins accumulated to a high level, but their content decreased to the level of the watered control 24 hours after the recovering from the water deficit. The cultivar ‘Manteigao Fosco 11’ grew better under one cycle of desiccation and recovered faster after the water stress had been relieved.