不同作物种苗对水中重金属镉去除的比较研究

Comparative Research on Cd Removal from Water by Different Kinds of Seedlings

以玉米、向日葵和蓖麻为实验材料,研究了3种作物种苗对镉的去除效果以及种苗生理生化指标的变化情况.结果表明,①随着处理时间的延长,溶液中镉含量逐渐降低,去除过程主要集中在前48 h.在1 mg.L-1和2 mg.L-1Cd溶液中,向日葵和蓖麻种苗的去除效果要好于玉米种苗的;而在5 mg.L-1和10 mg.L-1Cd溶液中,去除效果顺序为:蓖麻>玉米>向日葵.②种苗从溶液中吸收的镉绝大部分集中在根部.3种作物种苗对镉的富集能力大小顺序为:向日葵>蓖麻>玉米.③在不同镉处理浓度下,3种作物种苗的叶片质膜透性、根系活力、叶绿素含量和游离脯氨酸含量等生理生化指标均有不同程度的变化.向日葵的根系活力和脯氨酸含量均与镉积累量呈现显著相关性;蓖麻叶片的质膜透性和脯氨酸含量均与镉含量呈现显著正相关.3种作物种苗对镉都有一定的耐受性,而向日葵和蓖麻种苗的耐受性比玉米种苗的强.

Ecological effects of Cd removal from water and the changes of physiological and biochemical indexes of seedlings of maize, sunflower and castor-oil plant were investigated. The results showed that ① with the trial time lasting, Cd content in solution decreased, and the processes of Cd removal by seedlings of each concentration were almost completed in 48 hours. The removal effects of sunflower and castor-oil plant were better than those of maize at 1 mg·L^-1 and 2 mg·L^-1 Cd, whereas the best removal effects at 5 mg·L^-1 and 10 mg·L^-1 Cd were those of castor-oil plant, followed by maize and sunflower. ② Root absorbed the most proportion of Cd by all these three kinds of seedlings at every treatment. The ability of Cd accumulation by the three kinds of seedlings could be drawn as follow sunflower 〉 castor-oil plant 〉 maize. ③ The physiological and biochemical indexes of seedlings exposed to Cd for 72 hours had changed to different degree compared with control. The root activity and the proline content of sunflower both have significant relations with Cd accumulation, and the plasma membrane permeability and the proline content of castor-oil plant both have significant positive relations with Cd accumulation. Maize, sunflower and castor-oil plant could endure certain concentration of Cd, and the tolerance of sunflower and castor-oil plant are both greater than that of maize through general analysis of Cd accumulation and the changes of physiological and biochemical indexes.