Effects of zinc on cadmium uptake by spring wheat (Triticum aestivum, L.): long-time hydroponic study and short-time ~(109)Cd tracing study

摘要

To investigate effects of Zn on Cd uptake by spring wheat (Tritictim aestivum, L.) in solution culture, long-time hydroponic experiment (1 month) (Experiment 1) and short-time Cd isotope (~(109)Cd) tracing experiment (24 h) (Experiment 2) were conducted. In Experiment 1, spring wheat (cv. Brookton) was grown in nutrient solution at uniform cadmium concentration of 20 umol/L and 10 zinc concentrations (0, 1, 5, 10, 20, 100, 200, 500, 1000, 2000 urnol/L). In Experiment 2, spring wheat seedlings, pre-cultivated in complete nutrient solution, were treated with ~(109)Cd of uniform activity and the same series of Zn concentrations as those in Experiment 1 for 24 h. Cd concentrations in shoots and roots in Experiment 1 increased marginally but not consistently with Zn increasing at Zn rates of 1-200 umol/L, and then decreased significantly at high rates (>200 umol/L). In Experiment 2, the response of ~(109)Cd activities in shoots and roots to increasing Zn was greatly similar to the response of Cd concentrations to Zn increasing in Experiment 1. The results of the two experiments indicated that the short-time and long-time exposure of spring wheat to Zn had similar effects on Cd accumulation.