Relationship observed between salinity-tolerant callus cell lines and anatomical structure of Line 2 (Oryza sativa L.) indica under salinity stress

Abstract Rice is an important staple crop but is highly susceptible to abiotic stress. Polysaccharides (β-glucan) and BG serve as crucial functions in regulating plant development and growth, especially in responding to abiotic stress. Callus responds to BG and NaCl signals through various chemical and biochemical processes. However, no prior study on BG signals specific to in vitro plants or callus cultures of rice has been conducted. Therefore, the response of rice callus to BG pre-treatment was examined. The exogenous addition of BG to the stress media increased the salt tolerance of callus significantly though enhancing antioxidant activity. However, Na accumulation and Na/K ratio decreased significantly in callus throughout the experimental 3-month period. The results identified that Line 2 exposed to a salinity condition from callus, exhibits good growth characteristics and high biochemical activities. Furthermore, it had the better anatomical structure, chlorophyll content and net photosynthetic rate compared to Line 2, which was derived from control. BG as antioxidants, scavenge reactive oxygen species to mitigate possible injury on biomembranes under salt stress. The application of BG may induce an adaptive response in callus by stimulating antioxidant enzyme activities and showing the relationship between salt-tolerant callus cell lines and the histological structure of Line 2 shoot and root.