Background: Seawater intrusion causes many unfavourable effects on crops, especially rice, which is very sensitive to salt. Salinity stress reduces the growth and development of rice, thereby reducing the yield. This is an important issue affecting the food security of many countries in the world. This study focused on using oligochitosans to increase salinity tolerance and improve rice growth at the seedling stage. 
 
Methods: Dry and rice-sprouted seeds were treated with oligochitosan solutions of different molecular weights and concentrations and incubated in NaCl solution at a concentration of 0.6%. The salinity tolerance of rice seedlings was assessed through in vitro indices in the plants&rsquo; shoot length, number of leaves, number of roots (apical and lateral roots) and root length, fresh and dry weight, photosynthetic pigments, proline, total sugar and total protein. 
 
Result:&nbsp;Oligochitosan 5994 Da at a concentration of 75 ppm improved the growth of rice seedlings under salinity conditions. Oligochitosan 11126 Da at the concentration of 100 ppm improved the growth of rice seedlings under salinity stress in the investigation of dry seed treatment. The salinity tolerance of rice seedlings was observed through the increase of photosynthetic pigments, proline, and total sugar concentration and morphology.

​The Effects of Oligochitosans on the Growth of in vitro Rice Seedlings under Salinity Stress

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).&nbsp;

​The Effects of Oligochitosans on the Growth of in vitro Rice Seedlings under Salinity Stress

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

The Effects of Oligochitosans on the Growth of in vitro Rice Seedlings under Salinity Stress