Alleviation of salt stress by seed treatment with abscisic acid (ABA), 6-benzylaminopurine (BA) and chlormequat chloride (CCC) optimizes ion and organic matter accumulation and increases yield of rice (Oryza sativa L.)

摘要

Soil salinity is an increasing problem for agricultural production worldwide. Plant growth regulator (PGR)-treated seeds have the potential to produce plants with a greater salt tolerance as salt tolerance in established plants is greater than in germinating seeds. This study aimed at evaluating the effect of seed pre-soaking with abscisic acid (ABA), 6-benzylaminopurine (BA) and chlormequat chloride (CCC) on the amelioration of salt stress in rice cv. IR-6 in hydroponic culture and in saline field conditions. The study placed particular emphasis on osmoregulation and accumulation/partitioning of ions and organic osmotic matters. We found that the addition of PGRs as seed treatment agents or chemicals to rice cv. IR-6 has a significant role in reducing salinity stress. ABA was the most effective PGR in reducing Na+ and Cl- concentrations and Na+/K+ ratio, increasing K+ and Ca2+ concentrations, proline accumulation, soluble sugar content and grain yield. BA had the largest positive effect on soluble protein content. The three PGRs all had a significant positive effect on the grain yield of rice. Compared to control, ABA, BA and CCC treatments increased grain yield by 21%, 17% and 12%, respectively. Our results suggest that ABA was more effective than BA and CCC to ameliorate the toxic effects of salt stress in rice. It is economic to use these PGRs in the production system. Since they were used only for seed treatment and at very low concentration (10-5 or 10-6 M) their possible negative impact on human health can be avoided.