抗寒剂包膜对超甜玉米低温逆境下生理生化变化的影响

The effects of seed film coating with cold-tolerant agents on physiology and biochemistry changes of (supersweet) corn in low temperature stress.

试验以玉米sh2胚乳突变体(特甜1号和增甜2号)为材料,研究了低温逆境下A、B2种抗寒剂包膜超甜玉米种子对其生理生化变化的影响.结果表明,低温逆境下2种抗寒剂均显著提高了特甜1号种子发芽率、发芽指数、活力指数、壮苗率和幼苗素质.增甜2号2种抗寒剂处理的发芽率和壮苗率均与对照无显著差异.2个品种2种抗寒剂处理的苗高均显著高于对照,而根长均显著短于对照.低温逆境结束后,增甜2号2种抗寒剂处理的过氧化物酶和过氧化氢酶均显著高于对照,2个品种质膜相对透性和丙二醛含量均显著低于对照.与低温逆境前比,恢复生长3d后,2个品种2种抗寒剂处理的叶绿素含量增加幅度均比对照大.低温逆境后,2个品种脯氨酸含量提高;恢复生长3d后含量下降,但抗寒剂处理均显著低于对照并接近低温逆境前的水平.

The effects of seed film coating with cold-tolerant agents (A and B) on physiological and biochemical changes in supersweet corn, cv. Tetian No.1 and Zengtian No.2 (with sh_2 gene), were investigated under low temperature stress condition (at 5～6 ℃). After exposure of germinating seeds to low temperature stress, the germination percentage, germination index, vigor index, vigor of seedling percentage and seedling quality of seeds in Tetian No.1 coated with either of the two cold-tolerant (agents) were significantly higher than those of the uncoated controls. However, the percentage of seed germination and vigorous seedlings produced from the seeds were not significantly different between the seeds coated with cold-tolerant agents and the control seeds in Zengtian No.2. Shoot height was elevated and root length declined in both varieties after the seeds was coated with cold-tolerant agents. After low temperature stress, the activities of peroxidase(POD)and catalase(CAT)of seedlings from seeds coated with either of two cold-tolerant agents in Zengtian No.2 were significantly higher than those of the control, whereas the relative permeability of plasmmembrane and malondialdehyde(MDA)content of seedlings from the treated seeds were significantly lower than those of the control in both varieties. As compared with chlorophyll content before low temperature stress, the degree of increase in chlorophyll content of seedling leaves in the treatments of film coating with either of the two cold-tolerant agents was larger than that of the control after release from stress for three days in both varieties. The proline content of the leaves increased after low temperature stress and declined during the three-day recovering period. The restoration of proline content to normal level in seedlings from treated seeds was, however, more rapid than that from control seeds.