The Tolerance of Saline Conditions of Rice Seedlings in the Treatment of Oligochitosan

Background: Rice is one of the most important crops and is sensitive to salinity stress. Salt stress is a major abiotic stress that causes inhibition in plant growth or even plant death. Looking for a solution to enhance the salt tolerance of rice is very necessary. Methods: Rice sprouts with 2-3 mm of radicles were treated in four treatments: distilled water, 0.6% NaCl, oligochitosan 5994 Da (75 ppm) and 0.6% NaCl supplemented with 75 ppm of oligochitosan 5994 Da. The physiological and biochemical parameters and gene expression of rice seedlings were evaluated after seven days of treatment. Result: In the treatment of 0.6% NaCl, the development of rice seedlings was inhibited, but the salt-resistant systems were activated. The addition of oligochitosan maintained the growth of rice seedlings through the improvement of morphology, physiological parameters and the concentration of total sugar, proline and total protein. Oligochitosan raised the expression of genes related to proline biosynthesis (P5CS and P5CR) or genes related to antioxidant enzymes in salinity stress (cAPX, tAPX and sAPX).