干旱胁迫对苎麻苗期理化指标的影响

用PEG-6000对苎麻（Boehmeria nivea ）幼苗进行不同时间的干旱胁迫，测定胁迫后第0 d，2 d，4 d，6 d及8 d内其叶片生理生化指标，包括游离脯氨酸（Pro）、过氧化物酶（POD）、丙二醛（MDA）和过氧化氢酶（CAT）的活性，细胞质膜透性、叶绿素含量及内源激素的变化。结果表明：随时间延长，Pro，POD和CAT活性呈先升高后降低的趋势；细胞膜透性和MDA活性增加；叶绿素含量降低；赤霉素（GA）和吲哚乙酸（IAA）含量下降；脱落酸（ABA）含量上升。因此，苎麻的保护系统能够进行自身的调节以抵抗干旱伤害。

The Effects of Drought Stress on Physicochemical Index of the Seedling-Stage Ramie

The leaf physiological and biochemical indexes, including the activity changes of the free proline (Pro), peroxidase (POD), malondialdehyde (MDA) and activity of catalase (CAT), were measured within 0 to 8 d after treated with PEG-6000 as a drought stress on the seedling stage of ramie (Boehmeria nivea). The changes of the cytoplasmic membrane permeability, chlorophyll content, and the endogenous hormones were also tested. The results showed that the activity of POD and CAT was first increased, and then dropped with the drought time increasing. The cell membrane permeability and the contents of Pro and MDA activity were increased with the extension of treatment time. The content of chlorophyll was decreased, while the endogenous GA and the content of IAA were dropped, and the ABA content was raised. The results indicated that the protection systems of the ramie were able to protect itself from the damage of drought stress.