施氮量对水稻非结构性碳水化合物积累分配与颖花形成的影响

Effects of nitrogen application rate on accumulation and distribution of non-structural carbohydrates and spikelets formation in rice

以大穗型杂交粳稻浙粳优1758和常规粳稻苏香粳100为材料,设置3种施氮水平(105、210、315 kg·hm^(-2),分别记为N1、N2、N3处理)进行大田生产试验,探讨施氮量处理对水稻非结构性碳水化合物(non-structural carbohydrates, NSC)积累分配与颖花形成的影响。结果表明:施氮量影响2个不同穗型品种穗分化期茎鞘、叶片和幼穗NSC浓度和积累量,抽穗期茎鞘中NSC浓度和含量显著高于幼穗和叶片,中等施氮量N2处理有利于增加花前茎鞘NSC积累,促进花后NSC向籽粒转运,为获得高产奠定物质基础。施氮量影响枝梗与颖花的形成,并因稻穗不同部位而异,与N1和N3处理相比,N2处理总枝梗数、颖花分化数和现存数最高,而退化数和退化率最低;施氮量对一次枝梗和颖花以及上部二次枝梗和颖花的影响均不显著,但N2处理显著增加中、下部二次颖花的分化数并减少退化数,促进中、下部枝梗与颖花的形成,2个品种趋势一致。抽穗前20、10 d茎鞘中较高的NSC贮藏不利于2个粳稻品种幼穗枝梗和颖花的分化,相反会增加退化,而抽穗前15、5 d幼穗NSC积累量与枝梗和颖花的分化数与现存数呈显著或极显著正相关,与退化数呈显著或极显著负相关,是决定穗粒数形成的关键时期。

Using large-panicle hybrid rice Zhejingyou 1758 and conventional japonica rice Suxiangjing 100 as materials, three nitrogen application levels(N1, N2, N3;105, 210, 315 kg·hm^(-2), respectively) were set to carry out field production experiments, to investigate the effects of nitrogen treatment on accumulation and distribution of non-structural carbohydrates(NSC) and spikelets formation in rice. The results showed that nitrogen application rate affected the concentration and accumulation of NSC in stem-sheath, leaf and young panicle at spike differentiation stage of two panicle types. The concentration and content of NSC in stem sheath at heading stage were significantly higher than those in young panicle and leaf. Medium nitrogen application rate N2 treatment was beneficial to increase the accumulation of NSC in stem sheath before flowering and promote the transfer of NSC to grain after flowering, which laid the material foundation for high yield. Compared with N1 and N3, N2 treatment had the highest total number of branches and stems, the number of differentiated spikelets and the number of extant spikelets, while the number and rate of degradation were the lowest.However,N2 treatment significantly increased the number of secondary spikelets in middle and lower secondary spikelets and decreased the number of degenerated spikelets,and promoted the formation of middle and lower secondary spikelets and spikelets.The trends of the two cultivars were consistent.Higher NSC storage in the stem sheath 20 days before heading and 10 days before heading was not beneficial to the differentiation of spikelets and spikelets of the two japonica rice varieties,on the contrary,it would increase the degradation.However,the accumulation of NSC in the spikelets 15 days before heading and 5 days before heading had a significant or extremely significant positive correlation with the differentiation of spikelets and spikelets and the existing number,and a significant or extremely significant negative correlation with the degradation number.It is the key period to determine the formation of kernel number per spike.