海马齿对重金属Pb、Zn胁迫的生长及生理生化响应

Effects of Pb and Zn on the growth and physiological response of Sesuvium portulacastrum

关键词:  重金属  海马齿  生理生化  生长动态

Key words:  heavy metal  Sesuvium portulacastrum  physiological and biochemical  growth dynamics

摘要:

重金属污染是当前生态环境保护话题的一个热点,当环境污染后,重金属容易被植物体吸收、富集,阻碍植物的生长发育。海马齿(Sesuvium portulacastrum)是一种生长在海边沙地及河流入海口两岸滩涂地带的多年生肉质草本植物,拥有一套有别于淡土植物的遗传背景和耐盐碱生理机制。为了讨论其抗重金属逆境能力,用1/10的Hoagland营养液配制不同浓度的Zn²⁺、Pb²⁺溶液, 浓度梯度为0、5、10、25、50 μmol·L^-1(0 μmol·L^-1为对照组),在Pb、Zn单因子处理下对海马齿的生物量指标节间长度、鲜重、干重和海马齿生理生化指标叶绿素、丙二醛、脯氨酸、可溶性糖、可溶性蛋白和根系活力进行测定,研究其生理活动和生长动态。结果表明:叶片叶绿素含量下降,根系活力降低; 同时,高浓度的Pb、Zn离子对海马齿的相对生长率和节间长度存在明显的抑制作用; 蛋白质含量显著下降; 脯氨酸、可溶性糖、丙二醛能够被诱导且显著升高; 但同时,海马齿鲜重和干重并没有显著的变化。说明海马齿对重金属Pb、Zn具有一定的耐受性,为研究海马齿是否可以作为一种净化水源的植物提供理论参考依据。

Abstract:

Heavy metal pollution is a hot spot of the current ecological environment protection topic. When the environmental pollution happened,the heavy metal will be easily absorbed and enriched by the plants,and then affect the plant's normal growth. Sesuvium portulacastrum is a perennial herb with the fleshy stem. It grows in the coast land and salt tidal flats. It has its own salt tolerant mechanism and genetic background,which are different with the fresh water plant. In order to discuss the heavy metal resistance ability of S. portulacastrum, the changes in physiological activity and the growth of S. portulacastrum influenced by Pb and Zn were investigated. 1/10 Hoagland nutrient solution was used to prepare Zn ²⁺ and Pb²⁺ solutions with the concentrations from 0(CK),5,10,25 to 50 μmol·L^-1. Under the Zn ²⁺ and Pb²⁺ stresses and separately,the biomass indexes including the internode length,the fresh and dry weights, the physiological and biochemical indicators including the Chlorophyll content,proline and malondialdehyde activities, soluble sugar, soluble protein and the root activity were analyzed. The results showed that the obvious symptoms were observed in the decrease of the root activity and chlorophyll content in the leaves. The soluble sugar, the proline and malondialdehyde activities would be induced to increase under the stresses of single Pb²⁺ and Zn²⁺. The soluble protein, the relative growth rate and the panel length dropped significantly with the increase of Pb²⁺ and Zn²⁺ concentrations separately. But the fresh and dry weights of S. portulacastrum had no significant changes under the heavy metal stress. This result illustrated the S. portulacastrum on heavy metal Pb and Zn had a certain tolerance. This study will provide the data of theoretical reference whether Sesuvium portulacastrum can serve as a plant for water purification.