外源ABA对西瓜幼苗抗冷性和某些生理指标的影响

摘要

以5、10,15、20、25 mg/L 5种质量浓度的ABA处理三叶一心西瓜幼苗,研究ABA对西瓜幼苗抗冷性的影响.结果表明,叶面喷施ABA能有效提高西瓜苗的抗冷性,其中以20 mg/L的效果最好.ABA能显著增加西瓜苗叶片的SOD和CAT活性,有效减缓低温胁迫过程中西瓜苗叶片叶绿素和GSH含量的降低,以及MDA的积累,促进脯氨酸含量和可溶性糖含量增加,使AsA含量保持在相对稳定的水平.%The seedlings of watermelon at 3 leaf stage were treated with 5,10,15,20 and 25 mg/L of ABA and then exposed at 5 ℃ for 24 h in order to study the effects of ABA on chilling-tolerance. The chilling-tolerance of watermelon seedling can be increased with ABA treatment. The concentration of ABA at 20 mg/L showed the most effective results. The results showed that ABA could improve the activity of superoxide dismutase (SOD) and catalase (CAT),remarkably delay the decrease of chlorophyll and reduced glutathione hormone (GSH) content aswell as the increase of malonaldehyde (MDA) content in the leaves of watermelon seedling during low temperature stress. On the other hand,ABA could effectively promote the increase of contents of proline and soluble sugar in the leaves of watermelon seedling during low temperature stress. The ascorbic acid (ASA) content was maintained a steady level in leaves of watermelon seedling by ABA treatment.