镉、铅及其相互作用对小白菜根系生理生态效应的研究

EFFECT OF CADMIUM,LEAD AND THEIR INTERACTIONSON THE PHYSIOLOGICAL AND ECOLOGICAL CHARACTERISTICS OF ROOT SYSTEM OF Brassica chinensis

采用溶液培养方法，以镉、铅作为胁迫因子，研究了不同镉、铅浓度对小白菜根系生理生态的影响。实验结果表明：培养液中镉超过０．１ｍｇ／Ｌ以后，侧根数目减少，根的分枝程度降低，根系生物量和体积下降，根系生长发育受阻，根系不发达，根系对锰、锌的吸收能力受到抑制，根系活动降低，对硝酸盐吸收能力下降，蛋白质分解加快，游离氨基酸积累，氮代谢紊乱、失调。在含镉的培养液中，施入铅，由于铅的加入，加强了镉对根系的生理生态效应。

The physiological and ecological effects on root system of Brassica chinensis grown in hydroponic culture under the stresses at different concentration of Cd and Pb were studied.The experimental results show that the Cd solution concentration of greater than 0.1 mg/L significantly inhibited the root growth, decreased the number of lateral roots,suppressed the root branching,lowered the root biomass and volume,hindered the development of root system,depressed the uptake of Mn,Zn by root,reduced the root activities,accelerated the decomposition of protein in root,made the free amino acid accumulation,led to a reduction in nitrate contents in Brassica chinensis,and caused nitrogen metabolism disorder.When Pb had added to the culture solution containing Cd, physiological and ecological effects(toxicity) of Cd on root system was strengthened.