重金属铅对绢毛委陵菜生理特性和叶片超微结构的影响

摘要

以绢毛委陵菜(Potentilla sericea)为试验材料,采用盆栽试验方法,对不同浓度的铅胁迫下植物的叶片超微结构和生理特性进行了测定分析.结果表明,绢毛委陵菜在受到铅胁迫时,叶绿素含量随着时间的延长,浓度较低的处理组(<600 mg·kg-1)呈现先升高后下降的趋势,浓度较高的处理组(>600 mg·kg-1)呈现下降趋势;叶片可溶性蛋白的含量随着处理浓度及时间的增加不断下降;叶片丙二醛的含量与脯氨酸含量随处理浓度和时间的增加显著上升(P<0.05);超氧化物歧化酶活性随着浓度的增加以及时间的延长,呈现先下降后上升的趋势.随着铅胁迫的加强,铅对其幼苗的毒害作用增加.高浓度(2 000 mg·kg-1)下,部分细胞膜消失,叶绿体双层膜系统遭到破坏,基粒片层溶解,线粒体呈空泡化,嵴消失.由此可见,绢毛委陵菜对铅的耐受范围在600 mg·kg-1以下.%Potentilla sericea was employed as an experimental material in a pot experiment to study leaf ultrastructure and physiological characteristics under different gradients of lead stress.The results showed that the chlorophyll content under low concentration (<600 mg·kg-1) of Pb stress first increased, and then decreased, with the increase in duration of treatment time, whereas high concentrations (>600 mg·kg-1) of Pb stress showed a declining trend.The content of soluble protein was decreased.The MDA and free proline content all significantly increased.SOD activities first decreased, and then increased.With the increase of stress, the toxicity of lead to P.sericea seedlings increased.Under high Pb concentration (2 000 mg·kg-1), part of the cell membrane disappeared, the double membrane system of chloroplasts was destroyed, granum lamella was dissolved, mitochondrial vacuolization was serious, and the crest disappeared.These results showed that P.sericea is tolerant to lead up to concentrations of 600 mg·kg-1.