PHYSIOLOGICAL STUDIES ON THE INFLUENCE OF CYTOKININ OR GA_3 IN THE ALLEVIATION OF SALT STRESS IN SORGHUM PLANTS

摘要

Salt stress reduced the germination capacity, the root and shoot lengths, the production of fresh and dry matter, and the water content in sorghum (Sorghum bicolor L.) seedlings. This reduction was concomitant with a decrease in the contents of soluble proteins, free amino acids and nucleic acids (RNA and DNA), while proline and quaternary ammonium compounds (QACs) increased, especially at low and moderate (50 and 100 mM NaCl) salinity levels. Pre-soaking sorghum grains in either cytokinin or gibberellic acid (GA_3) partially or completely counteracted the adverse effects of salinity on the rate of germination, seedling growth and some metabolic mechanisms. Generally, exogenous applications of cytokinin or GA3 enhance the metabolic processes of sorghum plants and improve their tolerance to salt stress.