聚乙二醇对烟草种子活力及幼苗保护酶活性的影响

 以烟草种子为材料,用不同浓度的聚乙二醇（PEG）浸种不同时间,测定了浸种后种子萌发过程中和萌发后幼苗中某些生理生化指标及保护酶活性的变化。结果表明,PEG浸种能显著提高种子发芽率和幼苗活力指数,增强萌发种子的呼吸强度和淀粉酶活性,以20% PEG-6000浸种48 h效果最好。不同活力水平的种子经20%PEG处理后,幼苗活力指数明显提高,叶片超氧物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）等保护酶活性升高,膜脂过氧化产物丙二醛（MDA）和超氧阴离子（O₂^-）含量及电解质外渗率显著低于对照。研究还发现,PEG处理能提高种子在低温下的萌发率,增强幼苗抗冷性。

Effects of Seed Soaking in PEG on Seed Vigor and Protective Enzyme Activities of Tobacco Seedlings

The tobacco seeds were soaked in the different concentration PEG solution and treat them different time respectively. During germination seeds and growth seedlings, the physiological and biochemical index and the activity of protective enzyme were determined. The results showed that PEG could obviously promote the germination rate of tobacco seeds and vigor index of tobacco seedlings. It also could increase the intensity of respiration and α-amylase activities of germinating seeds and it had best effect with seed soaking in 20% PEG solution for 48 hours. The activity of superoxide dismutase(SOD), the peroxidase (POD) and catalase (CAT) increased compare to the control in different vigor levels seeds. While the content of MDA and the rate of O₂^- production and electric conductivity decreased significantly than those the control. This also indicate that increased germination rate of seeds and the chilling resistance of seedlings under lower temperature stress thought immersed pretreatment with PEG.