水分胁迫对玉米花粉活力和花受精能力的影响

抽穗期的玉米植株经不同强度水分胁迫处理后，花粉和花丝中ＳＯＤ活性下降，膜脂过氧化作用增强，对生物膜系统产生直接伤害，电解质外渗率增加，电镜下观察到线粒体和细胞质膜破坏，胞间连丝膨大变形，甚至断裂，粗糙内质网卷曲成空心筒状，甚至部分解体，导致代谢紊乱，物质运输受阻，影响花粉和花丝发育，降低雌穗花丝受精能力，减少穗粒数，从而造成减产。耐旱性不同的玉米，其花粉和花丝活力及花丝受精能力受水分胁迫的影响不同

Effects of Water Stress on Maize Pollen Vigour and Filament Fertility

Maize plants at tasseling stage were treated with light, moderate and severe water stress. The results showed that water stress had different negative effects on pollen vigour, filament vigour and filament fertility of maize cultivar with different drought-tolerance. The filament vigour was more sensitive to water stress than that of pollen vigour in all of the three cultivar tested. Water stress could decrease SOD activity and enhance membrane lipid peri- oxidation, led to direct injury on the biological membrane system and a sharp increase of elec trolyte leakage in maize pollen and filament tissue. The changing of ultrastructure showed that mitochondria and protoplasmic membrane of water stressed pollen and filament tissue were dam aged , then plasmodesmata were swollen, deformed or even ruptured and rough endoplasmic reticula curved into hollow cylinder. These ultrastructural changes led to disorder in metabolism, hindered the development of pollen and filament, decreased filament fertility, and finally result in a reduction of grain number and grain weight per ear.