玉米果穗不同部位子粒水分动态差异研究

为明确玉米果穗不同部位子粒含水率和脱水速率的动态变化差异,在春玉米区宁夏银川和夏玉米区河南新乡采用8个不同熟期和脱水速率的品种,将玉米果穗垂直等分为5个部位,定期测定不同部位子粒含水率,计算子粒脱水速率。结果表明,玉米生长中后期,果穗上部子粒含水率低于中下部子粒含水率,生理成熟前各部位子粒含水率的差值低于生理成熟后。参试品种生理成熟前20 d时不同部位子粒含水率极差低于3%,成熟期的极差值变幅为0.6%～5.2%,生理成熟后极差最大值可达6.2%。同一果穗自上而下子粒的脱水速率逐渐降低,品种之间有明显差异,先玉335、迪卡517和迪卡519果穗不同部位子粒脱水速率差异较大。果穗中部子粒脱水速率和平均脱水速率与不同部位子粒含水率的极差值呈负相关。

Study on Dynamic Difference of Kernel Moisture Content in Different Parts of Maize Ears

Eight cultivars with different growth stages and dehydration rates in Yinchuan, Ningxia(spring maize region) and Xinxiang, Henan(summer maize region) were used to study the dynamic difference of kernel moisture content and dehydration rate in the different parts of maize ear. We divided the maize ear into five parts vertically, then measured the kernel moisture content and calculated the kernel dehydration rate in different parts periodically. The results showed that during the middle and late stages, the kernel moisture content in the upper part of the ear was lower than that in the middle and lower parts. The differences of kernel moisture content in various parts of the ear were lower before physiological maturity than that after physiological maturity. The range of different parts of the kernel moisture content was less than 3% in test maize cultivars on 20 d before physiology maturity. The range at maturity was 0.6%-5.2%, and the maximum range was 6.2% after physiological maturity. The dehydration rate gradually decreased from the top to the bottom of the ear, and there were differences in different cultivars. The kernel dehydration rate in different parts of the ear was great in Xianyu335, Dika517 and Dika519. The range of kernel moisture content in different parts was negatively correlated with the dehydration rate of middle kernels and total ear.