Abstract:

In this study, wild Leymus secalinus seeds from 4 different regions of Tibet were collected as experimental materials, and the effect of Cu²⁺ and Zn²⁺ on the germination of wild Leymus secalinus seeds, seedling growth and MDA content in germ was preliminary researched. The study was to provide scientific reference for the evaluation and utilization of the resource of Leymus secalinus from Tibet at the heavy metal pollution areas. The results showed that the response of the seeds germination and seedling growth of different regions of Leymus secalinus seeds were not the same under the two metal ions stresses. The seed vigor index of Leymus secalinus decreased with the increase of Cu²⁺ content, and the difference was significant (P < 0.05).The seed germination and seedling growth were promoted under low concentration Zn²⁺ stress, while the high concentration inhibited the wild Leymus secalinus seeds in 4 different regions; MDA content in 4 different regions of the wild Leymus secalinus germ increased with the increase of the concentration of heavy metal ions under Cu²⁺ and Zn²⁺ stress, and there were significant differences (P < 0.05). It showed that heavy metal ions had damage to germ. The wild Leymus secalinus collected from Lhasa had the best resistance to Cu²⁺ and Zn²⁺ among the 4 collected seeds from different. It could be introduced, domesticated and chosen as the choice material for the restoration of heavy metal contaminated soil.

Key words: Wild Leymus secalinus, Different regions, Heavy metals, Seed germination, Physiological effect, Tibet

摘要：

本研究以采集于西藏4个不同区域的野生赖草（Leymus secalinus）种子作为试验材料，初步探究Cu²⁺、Zn²⁺对野生赖草种子萌发、幼苗生长和胚芽中MDA含量的影响，以期为赖草种子资源的评价与利用提供科学参考依据。研究表明，不同区域的赖草种子萌发和幼苗生长指标对两种金属离子胁迫的响应不尽相同，Cu²⁺胁迫下，赖草种子活力指数随着Cu²⁺的增加而降低，差异性显著（P < 0.05）；低浓度Zn²⁺对4个赖草种子的萌发和幼苗生长均表现为促进作用，而高浓度Zn²⁺则表现为抑制作用；Cu²⁺、Zn²⁺胁迫下4个不同区域的野生赖草胚芽中MDA含量均随着重金属离子浓度的增大而升高，存在显著性差异（P < 0.05），表明重金属离子对胚芽具有损害作用。Cu²⁺、Zn²⁺胁迫下，4个不同区域的野生赖草中采自拉萨的赖草对这两种重金属具有较好的抗性，可以进行驯化选育，以便作为重金属污染土壤恢复治理的选择材料。

关键词: 野生赖草, 不同区域, 重金属, 萌发特性, 生理效应, 西藏