红蛋植物对重金属镉、锌的吸收动态研究

Absorption dynamics of Cd and Zn by Echinodorus osiris

采用水培的方法研究了红蛋植物(Echinodorus osiris)对镉、锌的吸收动态。结果表明:无论是低镉(5 mg·L-1)还是高镉(15 mg·L-1)处理,长时间(27 d)培养时,红蛋地上部和地下部镉质量分数均持续增加,至收获时,低镉和高镉处理红蛋地上部镉质量分数分别为364.95和502.97 mg·kg-1;地下部镉质量分数分别达到1 762.81和2 742.95 mg·kg-1。短时间内,红蛋对镉的吸收速率随时间增加而降低,1.0 h内表现为快速吸收模式,而在1.0 h后表现为缓慢吸收模式。在低镉条件下,红蛋对镉的短时间吸收动态符合二次多项式数学模型,高镉条件下,红蛋对镉的吸收动态符合三次多项式数学模型。长时间(27 d)培养时,红蛋地上部锌和地下部质量分数的动态变化趋势基本一致,即先增加后减少再缓慢增加的趋势。低锌(100 mg·L-1)和高锌(400 mg·L-1)处理,红蛋地上部锌质量分数分别为2 211.38和3 190.47 mg·kg-1;地下部锌质量分数分别为3 067.89和3 303.85 mg·kg-1。短时间内,无论是低锌处理还是高锌处理,红蛋对锌的吸收动态均符合二次多项式数学模型,但是两者有所不同,低锌处理,红蛋吸收锌的速率短时间内略有降低,而高锌处理,红蛋对锌的吸收速率短时间内则持续增加。

The absorption dynamics of Cd and Zn by Echinodorus Osiris plant was studied by a hydroponic experiment.The results showed that the concentrations of Cd in the roots and shoots of Echinodorus Osiris increased with incubation time,which were 364.95 and 502.97 mg·kg-1in the shoots,1 762.81 and 2 742.95 mg·kg-1in the roots after 27 d incubation in a lower Cd concentration（5 mg·L-1） and a higher Cd concentration（15 mg·L-1） treatments,respectively.However,the Cd uptake rate decreased with incubation time with the faster absorption model was observed within 1h of the incubation and the slower absorption model was found after 1h incubation.The Cd uptake curve fitted the quadratic polynomial model and cubic polynomial model when plants grew in the lower and the higher Cd concentrations,respectively.The concentrations of Zn in the roots and shoots of Echinodorus Osiris also increased with time.The Zn concentrations in the shoots of Echinodorus osiris were 2 211.38 and 3 190.47 mg·kg-1after the plants grew 27 d in the lower（100 mg·L-1）and the higher（400 mg·L-1） Zn concentrations,respectively.The Zn concentrations in the roots of Echinodorus osiris reached 3 067.89 and 3 303.85 mg·kg-1in the lower Zn concentration and the higher Zn concentration treatments,respectively.The Zn uptake model of Echinodorus osiris fitted quadratic polynomial model in both treatments of the lower and the higher Zn concentrations within a short time（0-4 h） period.