The aim of this study is to investigate the effect of nitrogen (N) in the regulation of grain yield, growth, and physiology and biochemistry of fragrant rice under lead (Pb) stress. Three fragrant rice cultivars (Daohuaxiang, Basmati, and Yungengyou14) were grown under two N application levels (CK, 0 kg N ha −1 , and HN, 200 kg N ha −1 ) under Pb-contaminated soil. The grain yield, growth, antioxidant attributes, and N metabolism of fragrant rice cultivars were investigated. Results showed that compared with CK, HN treatment increased grain yield in Daohuaxiang, Basmati, and Yungengyou14 by 24.09%, 26.74%, and 23.29%, respectively. Improvement in the effective panicle, grain number per panicle, and 1000-grain weight and agronomic traits under HN treatment was detected. HN treatment decreased the seed setting rate in the three fragrant rice cultivars. In addition, the peroxidase (POD), catalase (CAT), and glutamate synthetase (GOGAT) activity in HN treatment were increased for the three fragrant rice cultivars at both heading stage and maturity as compared to CK. The correlation between the grain yield and the other investigated parameters has also been accessed. Yungengyou14 produced the highest partial factor productivity of N and agronomic use efficiency of N. Those results suggested that N could improve the grain yield resulted from affecting the growth and physiological response of fragrant rice grown under Pb-contaminated soil.

中文翻译：

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氮对铅污染土壤下香稻产量、抗氧化特性和氮代谢的调节作用

本研究的目的是研究氮（N）在铅（Pb）胁迫下对香稻产量、生长及生理生化的调控作用。三个香稻品种（稻花香、巴斯马蒂和运更油14）在两种施氮水平（CK，0 kg N ha -1 和HN，200 kg N ha -1 ）下在铅污染土壤下种植。研究了香稻品种的产量、生长、抗氧化特性和氮代谢。结果表明，与CK相比，HN处理使稻花香、巴斯马蒂和运更油14的籽粒产量分别提高了24.09%、26.74%和23.29%。检测到HN处理下有效穗数、每穗粒数、千粒重和农艺性状的改善。HN 处理降低了三个香稻品种的结实率。此外，与 CK 相比，HN 处理中三种香稻品种在抽穗期和成熟期的过氧化物酶 (POD)、过氧化氢酶 (CAT) 和谷氨酸合成酶 (GOGAT) 活性均增加。还访问了谷物产量与其他研究参数之间的相关性。运耕优14产生的氮的部分要素生产力和氮的农学利用效率最高。这些结果表明，在铅污染土壤下，氮可以影响水稻的生长和生理反应，从而提高粮食产量。与 CK 相比，HN 处理中三个香稻品种在抽穗期和成熟期的 谷氨酸合成酶 (GOGAT) 活性均增加。还访问了谷物产量与其他研究参数之间的相关性。运耕优14产生的氮的部分要素生产力和氮的农学利用效率最高。这些结果表明，在铅污染土壤下，氮可以影响水稻的生长和生理反应，从而提高粮食产量。与 CK 相比，HN 处理中三个香稻品种在抽穗期和成熟期的 谷氨酸合成酶 (GOGAT) 活性均增加。还访问了谷物产量与其他研究参数之间的相关性。运耕优14产生的氮的部分要素生产力和氮的农学利用效率最高。这些结果表明，在铅污染土壤下，氮可以影响水稻的生长和生理反应，从而提高粮食产量。