玉米与番茄间作对土壤镉吸收的影响

Effects of intercropping on cadmium uptake by maize and tomato

摘要:

为探究间作对作物吸收重金属镉 (Cadmium，Cd) 的影响，以Cd相对高积累番茄 (中蔬4号) 和相对低积累玉米 (金珠蜜甜玉米) 为试验材料，在Cd 3.70 mg/kg的污染水平下以单作、限制性间作、间作 3种种植方式进行了盆栽试验，研究间作后作物各部位Cd积累差异及其形成原因。结果表明，番茄和玉米间作和限制性间作所产番茄根、茎、叶中Cd含量均有所提高 (叶中Cd含量从13.52 mg/kg分别升高至24.94 mg/kg和27.30 mg/kg)；与未种植作物的对照组相比，非单作条件下番茄根围土壤的pH有所下降，酸性磷酸酶活性上升，而脲酶活性下降，且间作组变化幅度较大；间作还能改变作物根围微生物种群结构,提高对重金属吸收有促进作用的微生物种群的丰度，最终实现Cd高积累番茄对Cd的吸收能力提高。研究结果可为利用间作模式修复土壤重金属污染和保障食品安全提供参考。

Abstract:

In order to explore the effect of intercropping on the uptake of heavy metal cadmium (Cd), pot experiments were undertaken using three different planting methods: monoculture, restrictive intercropping and intercropping. The effects of Cd accumulation in different plant parts, and their causes, were examined using a plant species regarded as a relatively high heavy metal accumulator (tomato: Lycopersicon esculentum var. Zhongshu 4) and a species regarded as a relatively low heavy metal accumulator (maize: Zea mays L. var. Jinzhumi). Cd levels for all experiments were 3.70 mg/kg. Results indicate that restricted intercropping and intercropping of tomato and maize increased the accumulation of Cd (from 13.52 mg/kg to 24.94 mg/kg and 27.30 mg/kg in tomato leaf, respectively). Compared with the control group, pH levels in soil surrounding tomato roots in the intercropped samples decreased and the activity of acid phosphatase increased, while the activity of urease decreased. Intercropping can also change the structure of the crop root microorganism population, increase the abundance of microbiological species that promote the uptake of heavy metals, and finally achieve high accumulation of Cd in tomatoes. Our research results provide reference for controlling soil heavy metal pollution and ensuring food safety by using an intercropping model.