施氮量对小麦穗花发育及穗粒数的影响

Effect of Amount Nitrogen Applied on Young Spike Development and Kernel Number of Winter Wheat

为了解小麦穗发育与氮素营养的关系,通过田间试验,设置90、180、270kg·hm-2三个施氮量水平（分别用N1、N2和N3表示）,选用半冬性小麦品种豫麦49和弱春性品种太空6号为材料,研究了施氮量对小麦主茎幼穗长度、第九小穗小花发育进程、每穗总小穗数、不孕小穗数、小穗结实率、产量及其构成的影响。结果表明,随着时间的推移,小麦主茎幼穗长度对施氮量响应逐渐明显,豫麦49和太空6号分别表现为N3〉N2〉N1和N2〉N3〉N1。豫麦49第九小穗第4-6朵小花发育进程对施氮量响应差异显著,且分化程度随施氮水平的提高而增加;太空6号第3-6朵小花进程对施氮量响应差异显著,其中第3朵小花在发育进程前期N2处理快于N1、N3处理,中期和后期N2、N3处理快于N1处理,第4-6朵小花分化程度则一直表现为N2〉N3〉N1。不同施氮处理间总小穗数、不孕小穗数、小穗结实率、产量、穗粒数等指标差异亦显著,且品种之间对施氮反应存在差异,其中豫麦49的总小穗数、小穗结实率、产量、穗粒数呈N3〉N2〉N1,而太空6号呈N2〉N3〉N1;豫麦49小穗结实率呈N3〈N2〈N1,而太空6号呈N2〈N3〈N1。由此可见,施氮量对小麦产量的影响与其对小穗中部小花发育、每穗总小穗数、不孕小穗数和单穗结实率的影响相一致。

Semi-winter wheat cultivar Yumai 49and weak spring wheat cultivar Taikong 6were used in a field experiment with 3nitrogen application levels of 90（N1）,180（N2）,270（N3）kg·hm-2 to investigate the effects of nitrogen application on the spikelet length of main stem,development of the florets at different positions of the 9th spikelet,spikelet differentiation per spike,number of male sterile spikelets and spikelet setting rate,yield and its components.Results showed that along with wheat development,the spikelet length of the main stem response to nitrogen application obviously, as with the increasing of nitrogen application amount,Yumai 59showed N3〉N2〉N1,Taikong 6 showed N2〉N3〉N1.The 3rd-6th floret development of 9th spikelet of Yumai 49significantly responsed to the nitrogen application amount,the differentiation degree increased with the increasing of nitrogen application amount.The 3rd-6th floret development of the 9th spikelet of Taikong 6also obviously responsed to the nitrogen application amount,as the 3rd floret development at early period in N2was earlier than in N1and N3treaments,and at middle and later period in N2and N3treatemntswas earlier than in N1;the 4th-6th floret differentiation degree showed the trend of N2〉N3〉N1. Obvious differences among different nitrogen application amount were observed in the number of spikelet differentiation per spike,male sterile spikelet,spikelet setting rate,yield and spike number, and also between the two wheat cultivars.The number of spikelet differentiation per spike,seed setting rate,yield and spike number of Yumai 49showed as N3〉N2〉N1,while those of Taikong 6 showed as N2〉N3〉N1;the spikelet setting rate of Yumai 49showed as N3〉N2〉N1,while that of Taikong 6showed as N2〉 N3〉N1.It is concluded that nitrogen application amount had obvious effect on wheat yield and seed setting rate,and the effect was coherent with that of the floret development of spikelet,the number of spikelet differentiation per spike,male sterile spikelet and seed setting rate per spike;and the length of the spikelet at early period could reflect the floret development in certain degree.