EFFECT OF WATER STRESS ON RESPIRATION OF WHEAT

Abstract

A simple method of subjecting wheat seedlings to progressive water stress and of measuring the respiration rates is described. Slight water deficits increased CO2 output by about 20%, and more severe water stress decreased it by about 50%. Water stress caused significant changes in the concentrations of malate and citrate and of an unknown organic acid. Water stress strikingly decreased the level of malate in the roots and increased it in the shoots. It is suggested that the decrease in respiration caused by water stress cannot be attributed to an increased rate of dark fixation of carbon dioxide.