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【目的】研究不同密度群体棉花生育期、光合有效辐射(PAR)分布、叶面积指数(LAI)和干物质累积特征值的差异。【方法】供试品种为转Bt(Bacillus thuringiensis)基因杂交种中棉所75(CCRI 75)和常规品种鲁棉研28(SCRC 28),2012和2013年密度处理为1.5万、5.1万和8.7万株·hm~(-2)。【结果】不同密度群体在棉花不同生育期PAR存在显著差异,且冠层光透射率随密度增加而减少,不同种植密度的棉花群体冠层株型结构各不相同,不同群体棉花茎叶的空间分布决定PAR的分布;LAI随生育进程呈现出开口向下的抛物线,不同的密度群体LAI均在播种后60 d左右开始快速增加,100 d或110 d后LAI开始急速下降;随密度增加最大生物量累计值减少,且营养器官占单株总干物质的比例增加,而生殖器官所占比例下降;密度显著影响马克隆值大小,高密度下马克隆值最大。【结论】本研究为棉花田间管理、合理密植提供理论依据。
【Objective】 The objective of this study was to investigate the differences of cotton growth period, PAR distribution, leaf area index (LAI) and dry matter accumulation of different density groups. 【Method】 The tested varieties were CCRI 75 and SCRC 28, which were Bt (Bacillus thuringiensis) genetic hybrids. The density was 15,000, 51,000 and 8.7 respectively in 2012 and 2013 Million strains · hm ~ (-2). 【Result】 The results showed that there were significant differences in PAR at different growth stages among different density groups, and the light transmittance of canopy decreased with the increase of density. The canopy structure of cotton population varied with different planting densities. The LAI of the different density groups began to increase rapidly around 60 days after sowing, and LAI began to drop sharply after 100 days or 110 days. With the increase of density, the maximum biomass The cumulative value decreased, and the ratio of vegetative organs to the total dry matter per plant increased, while the proportion of reproductive organs decreased. The density significantly affected micronaire size and the highest micronaire value at high density. 【Conclusion】 This study provides theoretical basis for field management of cotton and rational close planting.