多效唑对繁茂度不同株型大豆产量及生理调控的影响

Effects of Paclobutrazol on Yield and Physiological Regulation of Soybean with Different Plant Types of Lush Degree

为了明确多效唑对繁茂度不同类型大豆产量及生理性状的影响,以株型繁茂度不同的两个类型品种杂交豆5号和九农30为试验材料,初花期喷施900 g/hm2多效唑,分析多效唑对繁茂度不同品种类型大豆生理和农艺性状调控。结果表明,多效唑提高了不同繁茂度大豆品种叶绿素含量、光合速率、气孔导度、蒸腾速率,增加了茎粗、分枝数;降低了大豆株高、中部节间长度及叶面积指数,且对不同类型品种产量影响差异显著。繁茂型杂交大豆品种,早发优势显著,叶面积指数较大,通过多效唑控制,降低了叶面积指数,增加叶片光合特性,防止徒长,利于田间透光,显著增加单株粒重、百粒重,从而显著增加产量。而收敛型品种最大叶面积指数接近最适叶面积指数范围,喷施多效唑后,叶面积指数进一步降低,虽然增加叶片光合速率,增加百粒重,但单株粒重显著降低,反而显著减产。说明施用多效唑增产效果与大豆冠层繁茂度密切相关,应根据冠层发育特征在合理情况下施用。

In order to clarify the effects of paclobutrazol on the yield and physiological traits of different types of lushsoybeans, the application of 900 g/hm2 paclobutrazol on the physiological and agronomic traits of different types oflush soybeans was analyzed by using two varieties with different plant types of lush soybeans as experimental materi-als at the early flowering stage. The results showed that paclobutrazol increased the chlorophyll content, photosyn-thetic rate, stomatal conductance, transpiration rate, stem diameter and branching number of soybean varieties withdifferent flourishing degrees. The plant height, middle internode length and leaf area index of soybean were de-creased, and the effects on yield of different types of soybean varieties were significant. With the control of pa-clobutrazol, LAI was reduced, the photosynthetic characteristics of the leaves were increased, and the light transmit-tability in the field was prevented. The grain weight per plant and the grain weight per hundred grains were signifi-cantly increased, thus the yield was significantly increased. However, the maximum LAI of the convergent cultivarswas close to the optimal LAI range, and the LAI was further decreased after the application of paclobutrazol. Al-though the leaf photosynthetic rate and 100-grain weight were increased, the grain weight per plant was significantlydecreased, but the yield was significantly decreased. The results indicated that the yield increase effect of using pa-clobutra was closely related to the canopy prosperity of soybean and should be applied under reasonable conditionsaccording to the characteristics of canopy development.