镉胁迫对矮生四季豆种子萌发和幼苗生长发育的影响

以水培法研究了不同浓度的Cd2＋溶液对四季豆种子萌发和幼苗生长发育的影响。结果表明：当Cd2＋浓度较低时，Cd2＋对种子萌发及幼苗生长发育毒害作用较小，一定浓度范围内（0.05～0.5mg/L）还有促生作用，高浓度Cd2＋(5～100mg/L)能严重抑制四季豆幼苗根及下胚轴的生长；Cd2＋胁迫对四季豆幼苗体内过氧化物酶 (POD)，超氧化物歧化酶（SOD）,过氧化氢酶（CAT）活性存在低浓度激活和高浓度抑制的效应，且同一浓度的Cd2＋对四季豆幼苗POD、CAT活性的抑制作用表现为根系大于下胚轴，Cd2＋浓度＞0.5mg/L时，根系SOD活性大于下胚轴中的活性；Cd2＋胁迫下，四季豆下胚轴和根的丙二醛（MDA）含量增加，且根部含量大于下胚轴的量。

Effects of Cadmium Stress on Seed Germination and Seedling Growth of Dwarf Beans

The effects of Cd2＋on Dwarf beans seed germination and seedling growth were studied with water culture experiments. The results showed that when the concentration of Cd2＋at low level, the effects of Cd2＋on the seed germination and seedling growth were not significant. Seeds germination were activated at a certain extent when Cd2＋ concentration ranged from 0.05mg/L to 0.5 mg/L concentrations. The roots and Hypocotyls of seedling exhibited a significant decrease in growth at higher level of Cd2＋concentrations（5～100mg/L）.The activities of peroxidase（POD）, superoxide dismutase（SOD）, catalase（CAT）could be enhanced at low Cd2＋concentrations but inhibited at higher concentration. The activities of POD, CAT were more inhibited in roots than in Hypocotyls at the same Cd2＋concentrations, while that of SOD was higher in roots than in Hypocotyls when the concentration of Cd2＋ was more than 0.5mg/L. The malondialdehyde(MDA) contents were continuously increased with Cadmium exposure in both roots and Hypocotyls.