两种基因型玉米苞叶的衰老生理特性

对大田条件下‘郑单958’（Zea mays‘Zhengdan 958’）和‘农大364’（Z.mays‘Nongda 364’）2种基因型玉米苞叶衰老过程中的生理特性进行了研究。结果表明，玉米苞叶衰老过程中，叶绿素和可溶性糖含量均呈先升后降的变化趋势，并在灌浆期达到最高值，且‘郑单958’的叶绿素降解速率高于‘农大364’；‘农大364’苞叶的可溶性糖含量在不同生育期均高于‘郑单958’。细胞膜透性和MDA含量均逐渐升高，并在蜡熟期达到最高值，其中‘农大364’细胞膜受损害程度和过氧化程度均低于‘郑单958’。苞叶中可溶性蛋白质含量呈递减趋势，在灌浆期至蜡熟期的降幅最明显，且‘郑单958’苞叶的可溶性蛋白质含量降幅低于‘农大364’苞叶。

Senescence physiological characteristics of husk of two maize genotypes

The senescence physiological characteristics of husk of two maize genotypes （Zea mays ＇ Zhengdan 958 ＇ and Z. mays ＇ Nongda 364＇ ） were studied under the field condition. The results showed that the contents of chlorophyll and soluble sugar in husk of two genotypes increased first and then decreased, and reached the peak values at milk-filling stage. The degradation rate of chlorophyll in husk of ＇ Zhengdan 958＇ was higher than that of ＇ Nongda 364＇ and the content of soluble sugar in husk of ＇ Nongda 364＇ at different growth stages was higher than that of ＇ Zhengdan 958＇. The cell membrane permeability and MDA content in husk of two genotypes increased gradually, and reached the peak values at dough stage, during which the extent of damage and peroxidation of cell membrane of ＇ Nongda 364＇ was less serious than that of ＇ Zhengdan 958＇ The content of soluble protein in husk of two genotypes decreased gradually during the senescence phase and the reduction from milk-filling stage to dough stage was the most obvious, in which the reduction of soluble protein content in husk of ＇ Zhengdan 958＇ was lower than that of ＇ Nongda 364＇.