PDF(Pubmed)
Abstract：
Optimized nitrogen (N) management (OPT), with reduced total N input and more N applied during panicle development, has been proved to increase grain yield of rice through panicle enlargement. However, the changes in panicle architecture and source of variation are not well understood. A hybrid rice variety named Tianyou 3618 was subjected to OPT and farmer\'s fertilizer practice (FFP) in early cropping seasons of 2016 and 2017. With 16.7 % less N input, OPT increased panicle size by 8.6 % and 27.4 %, and grain yield by 13.8 % and 12.3 % for 2016 and 2017, respectively. OPT had greater dry matter accumulation and N uptake from panicle initiation to heading, which bolstered panicle enlargement. The number of surviving florets per branch was quite constant under different N treatments for all primary, secondary, and tertiary branches, implying that panicle size was mainly determined by the number of branches rather than the number of florets per branch. Little change was observed between OPT and FFP in differentiation, degeneration and survival of primary branches and their florets. Surviving secondary and tertiary branches and their florets were significantly more under OPT than those under FFP. The increase in surviving secondary branches under OPT resulted from both enhanced differentiation and reduced degeneration. While the increase in surviving tertiary branches under OPT was merely from enhanced differentiation though their degeneration was also dramatically increased. Among the increased differentiated florets under OPT, 32.4%-36.3 % and 61.6%-67.7 % came from secondary and tertiary branches, respectively. Among the increased surviving florets under OPT, 62.2%-65.2 % and 32.5%-37.8 % came from secondary and tertiary branches, respectively. Both secondary branches and tertiary branches were principal contributors to the increase in panicle size of OPT. To our knowledge, this is the first report on the detailed changes in panicle architecture and their involvement in panicle enlargement and yield gain under OPT.
摘要：
优化氮（N）管理（OPT），随着总N输入的减少和穗发育过程中施加的N增加，已被证明可以通过穗部扩大来提高水稻的籽粒产量。然而,圆锥花序结构和变异源的变化尚不清楚。一个名为天优3618的杂交水稻品种在2016年和2017年的早期种植季节进行了OPT和农民的肥料实践（FFP）。N输入减少16.7%，OPT使穗型大小增加了8.6%和27.4%，2016年和2017年粮食产量分别下降13.8%和12.3%。OPT有更大的干物质积累和氮吸收从穗开始到抽穗，这支持了圆锥花序的扩大。在不同的氮素处理下，每个分支的存活小花数量是相当恒定的，次要,和三级分支机构，这意味着圆锥花序的大小主要取决于分支的数量，而不是每个分支的小花数量。OPT和FFP之间的分化几乎没有变化，主要分支及其小花的退化和存活。OPT下存活的二级和三级分支及其小花比FFP下显着更多。OPT下存活的次级分支的增加是由于分化增强和变性减少所致。虽然在OPT下存活的三级分支的增加仅仅是由于分化增强，尽管它们的退化也急剧增加。在OPT下增加的分化小花中，32.4%-36.3%和61.6%-67.7%来自二级和三级分支机构，分别。在OPT下幸存的小花中，62.2%-65.2%和32.5%-37.8%来自二级和三级分支，分别。二级分支和三级分支都是OPT穗大小增加的主要原因。据我们所知,这是关于OPT下穗型结构的详细变化及其参与穗型扩大和产量增加的第一份报告。
