改良剂对酸性土壤上伴矿景天铝毒缓解作用及镉锌吸收性的影响

Effects of amendments on the alleviation of aluminum toxicity and cadmium and zinc uptake by Sedum plumbizincicola in acid soils

摘要:

为探究不同改良剂对酸性土壤铝 (Al) 胁迫条件下镉 (Cd) 锌 (Zn) 超积累植物伴矿景天Sedum plumbizincicola生长以及镉和锌吸取修复效率的影响，分别添加不同种类改良剂 (钙镁磷肥 (CMP)、MgCO3、KH2PO4) 和不同浓度CMP进行温室盆栽试验。结果表明，CMP能够一定程度上提高土壤pH值并降低土壤交换性Al的浓度，MgCO3能够显著提高土壤pH值和降低土壤交换性Al的浓度，KH2PO4能够降低土壤中交换性Al浓度但未改变土壤pH值。施用适量的CMP (9.39 mg/kg) 能够提高伴矿景天生物量和Cd、Zn吸取修复效率，用量过高会抑制伴矿景天生长和Cd、Zn修复效率；施用MgCO3可增大伴矿景天生物量和Cd、Zn修复效率，施用KH2PO4反而抑制了伴矿景天生长。酸性土壤上施用适量的CMP和MgCO3能够缓解伴矿景天的铝毒作用，维持较高的重金属吸收效率。

Abstract:

To explore the effects of some chemical amendments on the plant growth and phytoextraction efficiencies of cadmium (Cd)/zinc (Zn) hyper accumulator Sedum plumbizincicola in acid soils with high aluminum (Al) toxicity, a greenhouse pot experiment was conducted. Different kinds and dosages of amendments including calcium- magnesium-phosphorus fertilizer (CMP), magnesium carbonate (MgCO3), potassium dihydrogen phosphate (KH2PO4) were added. The results showed that CMP and MgCO3 increased soil pH and decreased soil exchangeable Al concentration to some extent, while KH2PO4 reduced soil exchangeable Al concentration but had little effect on increasing soil pH. Proper application (9.39 mg/kg) of CMP could improve the biomass and Cd and Zn phytoextraction efficiencies by S. plumbizincicola but it would inhibit plant growth and phytoextraction performance when exceeding 9.39 mg/kg. MgCO3 addition enhanced plant metal uptake while KH2PO4 presented an opposite effect. It suggests that using CMP and MgCO3 could alleviate Al toxicity to S. plumbizincicola in acid soils and maintain relatively high metal extraction efficiency.