Response of water saturation deficit and some nitrogenous compounds in two maize cultivars to water stress

Water saturation deficit (WSD), amino acids, proline and protein content in the leaves were studied in two Egyptian maize (Zea mays, L.) cultivars; Composite 5 and Giza 2 grown under 0, -2, -4, -6, -8, and -lOxlO-5 MPa water potentials prepared from manitol. The study showed that WSD of the two cultivars increased with water stress but at different rates. The two cultivars showed also an equal daily increase in WSD under the same water stress. In both cultivars, water stress lead to the accumulation of protein, amino acids and proline. Higher rates of accumulation of proteins, amino acids and proline occurred at 0 to -2xHy5 MPa in both cultivars . Proline increased at rate higher than 15 mg/g D.W. per one MPa decrease in water potential and about 8 mglg D.W. per day of stress for both cultivars. According to the amount of accumulated proline in response to water stress cv. Composite 5 could be considered more tolerant than cv. Giza 2. Key words: Maize, (Zea mays, L. cvs. Composite 5 and Giza 2), water saturation deficit, (WSD), amino acids, proline, and protein