不同磷水平和介质pH对玉米和小麦镉积累的影响

Effects of different levels of P supply and pH on the content of cadmium in corn and wheat plants

将植株培养在４个磷浓度（０，０．１２，０．６，３．０ｍｍｏｌ／Ｌ），两个镉浓度（０，４．０μｍｏｌ／Ｌ）和两个ｐＨ（５．０，６．０）的组合溶液中，研究介质中不同磷浓度和ｐＨ对玉米和小麦体内含镉量的影响。结果表明，在介质ｐＨ６．０条件下，提高磷水平能降低上述两种作物根系和茎叶中镉的含量。培养液中磷浓度为０．６ｍｍｏｌ／Ｌ时，植株体内镉的含量最低，其干物质积累量最高。磷的供应过多或过少均使玉米和小麦体内镉含量上升，其生长量则有所下降。在介质ｐＨ５．０时，玉米和小麦体内的含镉量均高于ｐＨ６．０下的植株，且随供磷量的提高呈上升趋势。在有镉条件下，介质ｐＨ６．０时，适宜的磷浓度还能提高上述作物体内锌、钙、镁、钾的含量。这对保持植株体内养分平衡、促进植物的生长具有重要的作用。

Cadmium accumulation in corn and wheat plants was studied using a solution culture with cadmium added at 0,4 0 μmol/L,phosphorus at 0,0 12,0 6,3 0 mmol/L,and solution pH controlled at 5 0 and 6 0 respectively. With increasing P from 0 to 3 0 mmol/L,the root and shoot cadmium contents in corn and wheat plants were decreased. Both corn and wheat plants cultured with 0 6 mmol/L P had a reduced content of cadmium and increased dry weight of biomass,compared to those with 0,0 12,3 0 mmol/L P. At pH 5 0,the cadmium concentration in corn and wheat was higher than that of pH 6 0,and generally arose while increase in P supply. The moderate level of P supply with 0 6 mmol/L at pH 6 0 increased the Zn,Ca,Mg,and K contents in both species subject to 4 0 μmol/L Cd This is particularly important in the balance of nutrients in plants and enhancement in plant growth.