Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tas. 7001, Australia.
Plant Molecular Biology Laboratory, M. S. Swaminathan Research Foundation, III Cross Street, Taramani Institutional Area, Chennai 600113, India; and Forest Molecular Entomology Laboratory, Excellent Team for Mitigation (ETM), Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague 16500, Czech Republic.
Funct Plant Biol. 2022 Mar;49(4):351-364. doi: 10.1071/FP21336.
Wild rice species provide a rich source of genetic diversity for possible introgression of salinity stress tolerance in cultivated rice. We investigated the physiological basis of salinity stress tolerance in Oryza species by using six rice genotypes (Oryza sativa L.) and four wild rice species. Three weeks of salinity treatment significantly (P <0.05) reduced physiological and growth indices of all cultivated and wild rice lines. However, the impact of salinity-induced growth reduction differed substantially among accessions. Salt tolerant accessions showed better control over gas exchange properties, exhibited higher tissue tolerance, and retained higher potassium ion content despite higher sodium ion accumulation in leaves. Wild rice species showed relatively lower and steadier xylem sap sodium ion content over the period of 3weeks analysed, suggesting better control over ionic sodium xylem loading and its delivery to shoots with efficient vacuolar sodium ion sequestration. Contrary to this, saline sensitive genotypes managed to avoid initial Na+ loading but failed to accomplish this in the long term and showed higher sap sodium ion content. Conclusively, our results suggest that wild rice genotypes have more efficient control over xylem sodium ion loading, rely on tissue tolerance mechanisms and allow for a rapid osmotic adjustment by using sodium ions as cheap osmoticum for osmoregulation.
野生稻种为栽培稻的耐盐性可能的基因渐渗提供了丰富的遗传多样性。我们使用六种水稻基因型（Oryza sativa L.）和四种野生稻种研究了 Oryza 物种的耐盐生理基础。盐处理 3 周显著（P <0.05）降低了所有栽培和野生稻系的生理和生长指标。然而，盐诱导生长减少的影响在不同品种之间有很大的不同。耐盐品种表现出更好的气体交换特性控制，表现出更高的组织耐性，并保持较高的钾离子含量，尽管叶片中的钠离子积累较高。野生稻种在分析的 3 周期间表现出相对较低且稳定的木质部汁液钠离子含量，表明对离子钠离子木质部加载及其向芽的输送具有更好的控制，同时通过有效的液泡钠离子隔离来实现。与此相反，盐敏感基因型设法避免了初始 Na+加载，但长期以来未能做到这一点，并且表现出较高的汁液钠离子含量。总之，我们的结果表明，野生稻基因型对木质部钠离子加载具有更有效的控制，依赖于组织耐性机制，并允许通过将钠离子用作廉价的渗透调节剂来快速进行渗透调节。
