种植密度对不同小麦品种茎秆形态特征、化学成分及抗倒性能的影响

Effects of planting density on stem morphological characteristics,chemical composition and lodging resistance of different wheat varieties

[目的]本文旨在明确不同种植密度下小麦品种的抗倒性能差异,为小麦生产中品种选择及其合理密植提供依据。[方法]采用两因素裂区设计,主区为8个小麦品种,副区为2个密度处理,分析小麦茎秆形态结构、化学成分及抗倒伏能力的差异。[结果]小麦种植密度由基本苗300万·hm-2增加到450万·hm-2,小麦株高、基部节间长度及重心高度分别增加1.77%、6.11%和3.59%,基部节间直径及节间壁厚分别降低5.56%和10.25%,茎秆纤维素、半纤维素和木质素含量分别降低4.14%、7.60%和13.68%,机械强度下降17.59%,倒伏指数上升14.77%,最终导致倒伏率及倒伏程度显著上升,增幅达295.08%和53.57%。从品种来看,‘矮抗58’和‘洛麦23’的植株较矮,重心高度较低,基部节间长度较短,节间直径和节间壁厚较大,茎秆中纤维素、半纤维素和木质素含量较高,机械强度较大,倒伏指数较小,‘矮抗58’未发生倒伏现象,‘洛麦23’发生少量倒伏,产量也较高;‘烟优361’的植株和重心高度较高,节间直径和节间壁厚较小,茎秆中纤维素、半纤维素和木质素含量最低,机械强度最小,倒伏指数最大,倒伏率和倒伏程度最高,产量中等。相关分析表明:化学成分中纤维素、半纤维素和木质素含量均与抗倒性能显著相关,木质素含量对抗倒伏的贡献最大。[结论]密度过大不能达到增产效果,反而增加了倒伏概率。‘矮抗58’和‘洛麦23’的植株较矮,重心高度较低,基部节间粗短,结构性碳水化合物含量较高,抗倒性能较好,产量较高,适宜种植。

[Objectives]In order to give references to select the best variety and planting density in the area of wheat production,we have investigated the effects of planting density on lodging resistance of different wheat varieties.[Methods]The study was arranged in a split plot design with eight varieties as the main-plot and two planting densities as the sub-plot,in which we studied the differences of their stem morphological characteristics,chemical composition and lodging resistances.[Results]Experiment results showed when planting density increased from 3 million plants per hectare to 4.5 million plants per hectare,wheat plant height,gravity center height and basal internode lengths increased by 1.77%,6.11%and 3.59%,respectively.At the same time,internode external diameter and wall thickness reduced by 5.56%and 10.25%,and cellulose,hemicellulose and lignin content in the stem reduced by 4.14%,7.60%and 13.68%,respectively.What’s more,mechanical strength reduced by 17.59%,and the lodging index increased by 14.77%,so the lodging rate and the degree of lodging dramatically increased by 295.08%and 53.57%.In the terms of wheat varieties,the plant height and gravity center height of‘Aikang 58’and‘Luomai 23’were shorter,and their basal internode lengths were shorter,and internode external diameter and wall thickness were larger,and cellulose,hemicellulose and lignin content in the stem were higher.Further more,they also had large mechanical strength and small lodging index,and there was no lodging phenomenon for‘Aikang 58’and only a little for‘Luomai 23’.In addition,their yields were both high.However,‘Yanyou 361’had higher plant height and gravity center height,and its internode external diameter and wall thickness were small,and its cellulose,hemicellulose and lignin content in the stem were the lowest.Besides,it also had small mechanical strength and large lodging index,and its lodging rate and lodging level were the highest,and the output was medium.Correlation analysis showed that the chemical composition of cellulose,hemicellulose and lignin content were all associated with lodging resistance significantly,and the largest contribution to lodging resistance was lignin content.[Conclusions]In summary,large density planting cannot increase yield,instead it will cause high lodging rate.‘Aikang 58’and‘Luomai 23’possess shorter plant height and gravity center height,and thicker and shorter basal internodes.Besides,its structural carbohydrate content is higher,so they have good lodging resistance and higher yield.