ABSTRACT

Seed vigor is greatly influenced by harvest time. In this study, three conventional japonica rice varieties were used to investigate the optimal harvest time. Germination potential (GP), germination rate (GR), germination index (GI), vigor index (VI), mean germination time (MGT), field emergence rate (FER) and controlled deterioration germination rate (CDGR) were determined in 2018 and 2019. The results showed that seed vigor was firstly increased and then decreased with the increase in harvest time. Seed vigor reached maximum at approximately 50 days after flowering (DAF) while their yields had no significant changes compared to those at the normal harvest time (69 DAF). Compared to 69 DAF, GP, GR, GI, VI, FER, CDGR at 50 DAF were enhanced by 17.9%-113.3%, 1.4%-13.5%, 9.1%-35.8%, 19.8%-64.4%, 18.8%-130.3%, 7.5%-44.1%, respectively, and MGT was decreased by 10.0%-100.2%. On the basis, the changes in law of enzyme activity and gene expression related to seed vigor were analyzed. Interestingly, there were similar changing trends with seed vigor in peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), ascorbic acid peroxidase (APX), and gene expression of CAT3, OsAPX2, OsCSD3 with the increase of harvest time. Our study suggests that timely early harvest is effective for seed production of conventional japonica rice.

摘要

种子活力受收获时间的影响很大。本研究采用三种常规粳水稻品种被用来研究最佳收获时间。发芽势（GP）、发芽率（GR）、发芽指数（GI）、活力指数（VI）、平均发芽时间（MGT）、田间出苗率（FER）和可控变质发芽率（CDGR）于2018年测定， 2019. 结果表明，随着收获时间的增加，种子活力先升高后降低。种子活力在开花后约 50 天（DAF）达到最大值，而其产量与正常收获时间（69 DAF）相比没有显着变化。与69 DAF相比，50 DAF的GP、GR、GI、VI、FER、CDGR分别提高了17.9%-113.3%、1.4%-13.5%、9.1%-35.8%、19.8%-64.4%、18.8%-130.3 %、7.5%-44.1%，MGT下降10.0%-100.2%。基本上来说，分析了与种子活力相关的酶活性和基因表达规律的变化。有趣的是，过氧化物酶 (POD)、过氧化氢酶 (CAT)、超氧化物歧化酶 (SOD)、抗坏血酸过氧化物酶 (APX) 和CAT3、OsAPX2、OsCSD3随着收获时间的增加而增加。我们的研究表明，及时的早期收获对常规粳稻的种子生产是有效的。