Soil salinity is one of the important abiotic stress factors that affect rice productivity and quality. Research with several dicotyledonous plants indicated that the detrimental effects associated with salinity stress can (partly) be overcome by the external application of antioxidative substances. For instance, sodium selenate (Na2SeO4) significantly improved the growth and productivity of several crops under various abiotic stress conditions. At present there is no report describing the impact of Na2SeO4 on salinity stressed cereals such as rice. Rice cultivation is threatened by increasing salinity stress, and in future this problem will further be aggravated by global warming and sea level rise, impacting coastal areas. The current study reports on the effect of Na2SeO4 in alleviating salinity stress in rice plants. The optimal concentration of Na2SeO4 and the most efficient mode of selenium application were investigated. Selenium, sodium, and potassium contents in leaves were determined. Antioxidant enzyme activities as well as proline, hydrogen peroxide (H2O2), and malondialdehyde (MDA) concentrations were analyzed. In addition, the transcript levels for OsNHX1, an important Na+/H+ antiporter, were quantified. Treatment of 2-week-old rice plants under 150 mM NaCl stress with 6 mg l-1 Na2SeO4 improved the total biomass. A significantly higher biomass was observed for the plants that received Na2SeO4 by a combination of seed priming and foliar spray compared to the individual treatments. The Na2SeO4 application enhanced the activity of antioxidant enzymes (SOD, APX, CAT, and GSH-Px), increased the proline content, and reduced H2O2 and MDA concentrations in plants under NaCl stress. These biochemical changes were accompanied by increased transcript levels for OsNHX1 resulting in a higher K+/Na+ ratio in the rice plants under NaCl stress. The results suggest that Na2SeO4 treatment alleviates the adverse effect of salinity on rice plant growth through enhancing the antioxidant defense system and increase of OsNHX1 transcript levels.

中文翻译：

---

结合种子引发和叶面喷施硒酸钠处理可缓解水稻盐分胁迫。

土壤盐分是影响水稻生产力和品质的重要非生物胁迫因素之一。对几种双子叶植物的研究表明，与盐分胁迫相关的有害作用可以（通过外部应用）抗氧化物质来克服。例如，硒酸钠（Na2SeO4）在各种非生物胁迫条件下可显着改善几种作物的生长和生产力。目前，尚无关于Na2SeO4对盐分胁迫谷物（例如大米）的影响的报道。盐分压力的增加威胁着水稻的种植，未来全球气候变暖和海平面上升会影响沿海地区，这一问题将进一步恶化。目前的研究报道了Na2SeO4缓解水稻盐分胁迫的作用。研究了Na2SeO4的最佳浓度和最有效的硒施用方式。测定叶中硒，钠和钾的含量。分析了抗氧化酶的活性以及脯氨酸，过氧化氢（H2O2）和丙二醛（MDA）的浓度。另外，对OsNHX1（一种重要的Na + / H +反转运蛋白）的转录水平进行了定量。用6 mg l-1 Na2SeO4处理150 mM NaCl胁迫下的2周龄水稻植株，可提高总生物量。与单独处理相比，通过种子启动和叶面喷施的组合，观察到接受Na2SeO4的植物的生物量明显更高。Na2SeO4的应用增强了抗氧化酶（SOD，APX，CAT和GSH-Px）的活性，增加了脯氨酸的含量，降低NaCl胁迫下植物中的H2O2和MDA浓度。这些生化变化伴随着OsNHX1转录水平的升高，导致NaCl胁迫下水稻植株的K + / Na +比值更高。结果表明，Na2SeO4处理通过增强抗氧化防御系统和增加OsNHX1转录水平减轻了盐分对水稻植物生长的不利影响。