State Key Laboratory of Crop Biology, Agronomy College, Shandong Agricultural University, Taian, 271018, China.
Plant Mol Biol. 2019 Mar;99(4-5):461-476. doi: 10.1007/s11103-019-00830-0. Epub 2019 Feb 1.
ABA/GA ratio, stress resistance, carbon and nitrogen metabolism, and chromatin structure play important roles in vigour differences of seeds located at different maize ear positions. Seed vigour, which ensures rapid and uniform field emergence across diverse environments, differs at different maize ear positions. However, little is known regarding the associated mechanisms. In this study, we determined that seed vigour, stress resistance, and carbon and nitrogen metabolism were higher in seeds from middle and bottom section of the ear, while the ABA/GA ratio in the embryos was significantly lower. Compared with the seeds subjected to repeated pollination during silking, less variation in seed vigour and the ABA/GA ratio in the embryos was observed in seeds at different ear positions subjected to single pollination after complete silking. This indicated that single pollination can reduce, but not eliminate, the differences in seed vigour at different ear positions. RNA-seq analysis indicated that the seed vigour differences at the different locations of the maize ears of the single pollinated treatment were related to carbon and nitrogen metabolism. In contrast, the differences in seed vigour under repeated pollination were related to chromatin structure. The present study contributes to our understanding of the mechanisms underlying differences in seed vigour at different positions on the maize ear.
ABA/GA 比值、抗逆性、碳氮代谢和染色质结构在不同玉米穗位种子活力差异中起重要作用。种子活力确保了在不同环境条件下快速而均匀的田间出苗，而不同玉米穗位的种子活力则不同。然而，相关机制知之甚少。本研究表明，中部和下部穗位的种子活力、抗逆性和碳氮代谢较高，而胚中的 ABA/GA 比值显著较低。与抽丝期反复授粉的种子相比，完全抽丝后单授粉的不同穗位种子活力和胚中 ABA/GA 比值的变化较小。这表明，单授粉可以减少但不能消除不同穗位种子活力的差异。RNA-seq 分析表明，单授粉处理不同玉米穗位种子活力差异与碳氮代谢有关。相比之下，重复授粉条件下种子活力的差异与染色质结构有关。本研究有助于我们理解玉米穗上不同位置种子活力差异的机制。
