镧对镉胁迫下菜豆(Phaseolus vulgaris)幼苗生长的影响

以菜豆(Phaseolus vulgaris)为实验材料,以水培方法研究了La对Cd抑制对菜豆幼苗生长与代谢的影响.结果表明,在30μmol·L^-1Cd剂量伤害下,菜豆的生长受到严重抑制,主要表现为株高、主根长下降31.1%和39.2%,叶面积、叶、茎、根的鲜重、干重分别降低48.0%,42.7%、29.6%、25.0%、26.7%、61.3%、49.4%.在50μmol·L^-1Cd剂量伤害下,其生理生化特性发生变化,叶绿素含量、根系活力下降23.5%和28.7%,质膜透性、MDA含量、CAT和POD活性增加5.58%、28.6%、0.6%、7.0%,且随Cd处理时间的延长,伤害加重.叶面喷施10 mg·L^-1 La 1次,对镉污染下的菜豆幼苗的生长与代谢有一定的缓解效应,可减轻镉对幼苗的伤害程度.这与La能提高菜豆幼苗叶绿素含量(30.0%),降低细胞膜透性(0.87%)和MDA含量(9.5%),维持CAT(0.1%)和POD活性(1.6%)等多重作用相关.

Effects of La on the Growth of Kidney Bean Seedling under Cd Stress

In this study, kidney bean (Phaseolus vulgaris) was used as experiment-material, and effects of lanthanum on growth and metabolism of kidney bean seedling under cadmium stress was studied by water culture. The results showed that kidney bean seedling was chronically harmed by 30 mumol.L-1 Cd2+, however, its height and main root were reduced about 31.1% and 39.2%, meanwhile, leaf area, fresh and dry weight of leaf, stem and root were decreased 48.0%, 42.7%, 29.6%, 61.3% and 49.4% respectively. With acute damage of 50 mumol.L-1 Cd2+, physiological and biochemical characteristics of seedling changed greatly, e.g., chlorophyll content and root activity were decreased about 23.5% and 28.7%, cell membrane permeability, the malonydialdehyde (MDA) content, activities of catalase (CAT) and peroxidase (POD) were increased 5.58%, 28.6%, 0.6% and 7.0% respectively. And with longer treatment time, the damage became more serious. When 10 mg.L-1 La was used to spray on kidney bean seedling under cadmium stress one time, growth and metabolism of seedling was obviously reconditioned and the damage of Cd pollution was reduced. It is proved, by the experiment, that La can improve chlorophyll content(30.0%) and reduce cell membrane permeability (0.87%) and content of MDA(9.5%), and keep the activities of CAT (0.1%) and POD(1.6%) of kidney bean seedling.