干旱胁迫对千屈菜种子萌发和幼苗生长的影响

Effects of drought stress on seed germination and seedling growth of Lythrum salicaria

摘要:

以千屈菜(Lythrum salicaria)种子为试验材料，采用不同浓度聚乙二醇(PEG ‐6000)模拟干旱条件，研究干旱胁迫对种子萌发和幼苗生长的影响。结果表明：随 PEG 浓度的增加，千屈菜种子的发芽率、发芽势和发芽指数及幼苗的根长、株高和鲜重均呈先升高后降低的趋势，且在 PEG 体积分数 5% 时达到最大。幼苗的脯氨酸及可溶性蛋白含量在 PEG 体积分数 25% 达到最大，超氧化物歧化酶及过氧化氢酶活性在 PEG 体积分数 5% 达到最大。可溶性糖含量及过氧化物酶活性先升高后降低且相同浓度 PEG 处理均高于对照组。丙二醛含量及抗坏血酸过氧化物酶活性随 PEG 浓度的增加而增加。相关性分析表明：PEG 浓度与种子萌发和幼苗生长各指标呈负相关，与幼苗各生理指标呈正相关。综上所述，千屈菜的抗旱性是由多种因素共同决定。

Abstract:

The effects of drought stress on seed germination and seedling growth of Lythrum salicaria were stud‐ ied by simulating drought conditions with different concentrations of polyethylene glycol(PEG ‐6000). The results showed that with the increase of PEG concentration，the seed germination rate，germination potential，germination index，root length，plant height and fresh weight of the seedlings increased firstly and then decreased，and reached the maximum at PEG 5%. The contents of proline and soluble protein reached the maximum in PEG 25%，and the activities of superoxide dismutase and catalase reached the maximum in PEG 5%. The soluble sugar content and per‐ oxidase activity increased first and then decreased，and were higher than those in the control group. The content of malondialdehyde and the activity of ascorbate peroxidase increased with the increase of PEG concentration. The cor‐ relation analysis showed that PEG concentration was negatively correlated with various indexes of seed germination and seedling growth，and positively correlated with various indexes of seedling physiology. In conclusion，the drought resistance of Lythrumsalicaria is determined by multiple factors rather than a single factor.