Rice, one of the most important staple food crops in the world, is highly sensitive to soil salinity at the seedling stage. The ultimate yield of this crop is a function of the number of seedlings surviving after transplantation in saline water. Oryza sativa cv. IR64 is a high-yielding salinity-sensitive variety, while Pokkali is a landrace traditionally cultivated by the local farmers in the coastal regions in India. However, the machinery responsible for the seedling-stage tolerance in Pokkali is not understood. To bridge this gap, we subjected young seedlings of these contrasting genotypes to salinity and performed detailed investigations about their growth parameters, ion homeostasis, biochemical composition, and photosynthetic parameters after every 24 h of salinity for three days. Taken together, all the physiological and biochemical indicators, such as proline accumulation, K⁺/Na⁺ ratio, lipid peroxidation, and electrolyte leakage, clearly revealed significant differences between IR64 and Pokkali under salinity, establishing their contrasting nature at this stage. In response to salinity, the F_v/F_m ratio (maximum quantum efficiency of Photosystem II as inferred from Chl a fluorescence) and the energy conserved for the electron transport after the reduction of Q_A (the primary electron acceptor of PSII), to Q_A⁻, and reduction of the end electron acceptor molecules towards the PSI (Photosystem I) electron acceptor side was higher in Pokkali than IR64 plants. These observations reflect a direct contribution of photosynthesis towards seedling-stage salinity tolerance in rice. These findings will help to breed high-yielding crops for salinity prone agricultural lands.

水稻是世界上最重要的主食作物之一，在苗期对土壤盐分高度敏感。这种作物的最终产量是在盐水中移植后存活的幼苗数量的函数。水稻简历。IR64是高产盐分敏感品种，而Pokkali是印度沿海地区当地农民传统种植的地方品种。然而，负责博卡利幼苗期耐受性的机制尚不清楚。为了弥补这一差距，我们将这些对比基因型的幼苗置于盐度环境中，并在每 24 小时盐度处理三天后对其生长参数、离子稳态、生化组成和光合参数进行详细调查。综合所有生理生化指标，如脯氨酸积累、K ⁺ /Na ⁺比率、脂质过氧化和电解质泄漏，清楚地揭示了 IR64 和 Pokkali 在盐度下的显着差异，在这个阶段确立了它们的对比性质。响应盐度，F _v / F _m比率（从叶绿素 a 荧光推断的光系统 II 的最大量子效率）和Q _A（PSII 的初级电子受体）还原后为电子传输保存的能量，问_一个^-，并且末端电子受体分子向 PSI（光系统 I）电子受体侧的还原在 Pokkali 中高于 IR64 植物。这些观察结果反映了光合作用对水稻幼苗期耐盐性的直接贡献。这些发现将有助于为易受盐碱化的农田培育高产作物。