伴矿景天和鹅掌柴间作系统中根系相互作用对植物生长和镉锌吸收的影响

为明确不同物种根系间的相互作用对植物生长和重金属元素吸收的影响,以Cd、Zn超积累植物伴矿景天与花卉植物鹅掌柴为材料,研究二者根系相互作用及对植物生长和Cd、Zn的影响。结果发现,二者根系具有相互抑制生长的作用。单作条件下伴矿景天的Cd、Zn吸收量最高,分别达0.812、19.6 mg/盆;较单作相比,无分隔间作条件下伴矿景天对土壤Cd、Zn吸收降低分别达30.0%和30.6%。两种植物根系改变了土壤养分性质,对土壤钾和磷的利用分别具有竞争和互补作用,但其有效态含量并未降低到亏缺水平,养分竞争可能不是两种植物根系相互作用的主要因素。水培试验表明鹅掌柴根系分泌物对伴矿景天的生长和Cd吸收具有抑制作用。

Root Interactions and Effects on Growth and Cadmium/Zinc Uptake by Sedum Plumbizincicola and Schefflera Arboricola in Intercropping System

Phytoextraction has advantages of eco-friendly and low-cost compared with other remediation methods for polluted soil, and the intercropping of hyperaccumulators with crops is a common implementation method in phytoextraction. In the current study, a pot intercropping experiment was carried out to research the root interactions between Sedum plumbizincicola and Schefflera arboricola, and the plant growth and Cd/Zn uptake of the intercropping system. When S. plumbizincicola intercropped with S. arboricola, the root-root interaction inhibited the root growth and Shoot Cd and Zn uptake of each other. The Cd and Zn removal rates of the intercropping system were lower than that of S. plumbizincicola single planting for 30.0% and 30.6% respectively. Soil nutrient properties were changed by the roots of the two plants, and there was competitive and complementary utilization of soil K and P, respectively. Both the concentrations of soil available K and P did not decrease to the deficit level, indicating that nutrient competition may not be the main factor of the root-root interaction of the two species. In a supplementary hydroponic experiment, the root exudates of S. arboricola had an inhibitory effect on the growth and Cd uptake of S. plumbizincicola, indicating the allelopathy inhibition was one of the crucial mechanisms of root-root interaction between the two species likely.