分蘖高于主茎是困扰高粱(Sorghum bicolor)品种整齐度和机械化生产的重要因素之一, 内源激素及其互作效应在植物株高建成过程中起着关键的调控作用。为探索内源激素对高粱主茎和分蘖株高差异的影响, 利用主茎和分蘖高度一致的高粱品系K35-Y5和分蘖高于主茎的高粱品系1383为材料测定了4个时期主茎孕穗期、分蘖孕穗期、主茎开花期和分蘖开花期主茎与分蘖的株高性状和内源激素含量分析二者的变化特征及其相关性。不同时期主茎与分蘖株高差异变化分析发现, GA3在主茎和分蘖中的变化趋势与株高基本一致; ABA在K35-Y5主茎和分蘖间趋势基本一致, 在1383主茎开花期时分蘖明显高于主茎。IAA、ICA、tZR、IPA、Dx和JA含量随生育时期总体呈下降趋势; ACC、SA、JA和H2JA无明显变化规律。相关性分析得出, 在分蘖孕穗期、主茎开花期和分蘖开花期, 分蘖和主茎的株高差异与GA3相对含量为显著正相关; 且在主茎开花期和分蘖开花期, 分蘖和主茎的株高差异与GA3/ABA相对比值为显著正相关。综上所述, 在分蘖孕穗期、主茎开花期和分蘖开花期, GA3相对含量与主茎和分蘖株高差异密切相关。通过GA3处理和石蜡切片, 我们发现外施GA3影响细胞伸长来实现对株高整齐一致株型的改良, 将为选育适宜机械化生产高粱品种具有重要意义。

Higher tiller than stem is one of the important factors that hinder the uniformity and mechanical production of Sorghum bicolor. Endogenous hormones and their interaction effects play a key role in plant height building. To further explore the effects of endogenous hormones on height difference between stem and tiller of sorghum, Sorghum K35-Y5 with the same height of stem and tiller and 1383 with higher tiller than stem were used to measure the plant height and endogenous hormone contents in main stem booting stage, tiller booting stage, main stem flowering stage and tiller flowering stage, and analyze the dynamic change and correlation. The difference of height of stem and tiller in different stages showed that the stem of K35-Y5 was higher than that of tiller in the first three periods, and the height of[1] stem and tiller was basically the same at tiller flowering stage. The stem height of 1383 was higher than that of tiller in main stem booting stage, the height of stem and tiller was basically the same in tiller booting stage, and the height of tiller was higher than that of stem in the latter two stages. The analysis of dynamic change of endogenous hormone in different stages showed that GA₃ content in stem and tiller was basically consistent with the change of plant height. The dynamic change of ABA in K35-Y5 stem and tiller is basically the same, was significantly higher than stem of 1383 tiller in main stem flowering stage. The contents of IAA, ICA, tZR, IPA, Dx and JA showed a decreasing trend. ACC, SA, JA and H₂JA had no obvious characteristics. The correlation analysis showed that the difference of tiller and stem was positively correlated with the relative content of GA₃ at tiller booting stage, main stem flowering stage and tiller flowering stage, and positively correlated with the relative ratio of GA₃/ABA at main stem flowering stage and tiller flowering stage. Above of all, the height difference of stem and tiller was closely related to the relative content of GA₃ at tiller booting stage, main stem flowering stage and tiller flowering stage. Through the treatment of GA₃ and paraffin section, we found that spraying GA₃ affects cell elongation to achieve the improvement of plant height uniformity. This will be of great significance for the breeding of sorghum varieties suitable for mechanized production.