Influence of abscisic acid and benzyl adenine on some growth characters, endogenous hormones and some chemical constituents of cotton plants grown under drought stress.

摘要

Pot experiments were carried out in the greenhouse of the National Research Centre, to study the influences of ABA and BA on some growth characters, endogenous hormones, amino acid (proline), lipid peroxidation and membrane electrolyte leakage of cotton plants grown under drought stress conditions. The obtained results showed that drought stress conditions at flowering and fruiting stage caused reduction in all the studied growth characters (plant height, number of leaves/plant, leaf area, fresh weight of stem and leaves and fresh weight of the whole plant). The results indicated that water shortage at flowering stage was more effective on growth parameters than that induced at fruiting stage. Spraying cotton plants grown under drought stress with ABA at the rate of 75 ppm and BA at 150 ppm caused obvious changes in all the above growth characters. Drought stress conditions caused obvious increase in the endogenous content of ABA and amino acid proline. Pronounced reduction in the amounts of endogenous IAA, GA₃ and cytokinins were detected under water shortage treatments in comparison with that obtained from the plants subjected to normal irrigation. Exogenous application of ABA on cotton plants under drought stress led to increase in the endogenous contents of ABA and cytokinins. Spraying cotton plants grown under drought stress with BA caused increase in the endogenous content of IAA, GA₃ and cytokinins. Application of ABA and BA at the two used rates decreased significantly malondialdehyde (MDA) contents which in turn improved cell membrane of cotton plants grown under water shortage by reducing iipid peroxidation property of the cell membrane.