酸性土壤上伴矿景天铝毒的缓解技术研究

Alleviating Aluminum Toxicity to Cadmium Hyperaccumulator Sedum plumbizincicola in Acid Soils

为缓解酸性土壤上铝(Al)毒对重金属污染超积累植物生长及重金属吸收的抑制作用,利用水培和盆栽试验比较了不同措施对镉(Cd)超积累植物伴矿景天的Al胁迫缓解作用。结果发现:(1)在水培条件下,锌添加促进了Al胁迫下伴矿景天根表Cd2+吸收速率,而添加氯化钙或柠檬酸没有显著的作用;(2)在盆栽试验条件下,添加石灰处理显著提高了土壤p H,促进了伴矿景天生长和地上部对Cd的吸收,但添加生物质炭或柠檬酸没有显著缓解Al毒对伴矿景天生长和Cd吸收的抑制,添加柠檬酸反而加剧了土壤酸化,提高了土壤Al的活性;(3)在伴矿景天与荞麦间作条件下,其一定程度上降低了土壤的Al活性,在合适的种植密度下并未显著影响伴矿景天单株地上部Cd吸收量。综上,酸性土壤上耐Al作物与修复植物间作结合添加改良剂调控Al毒,能够不显著降低土壤Cd的有效性和修复植物的Cd吸收,进而实现污染土壤的边生产边修复。

To alleviate aluminum(Al) toxicity to the normal growth and efficient metal removal by hyperaccumulators in acid soils, the efficiencies of different strategies to relieve Al stress on cadmium(Cd) hyperaccumulator Sedum plumbizincicola were compared. The results show that in the hydroponic experiment, Zn addition significantly enhances root Cd2+uptake rate by S.plumbizincicola under Al stress while adding CaCl2or citric acid to solution has no significant effect on root Cd2+uptake. In the pot experiment, adding lime significantly increases soil pH, and enhances the growth and shoot Cd uptake of the hyperaccumulating plant. However, adding rice or maize biochars, or citric acid in soil does not significantly alleviate the inhibition of plant growth and Cd uptake raised by Al stress. In contrast, adding citric acid aggravates soil acidification.Agricultural strategy of intercropping with S. plumbizincicola and buckwheat was also used to alleviate Al stress, which decreases soil Al activity to some extent and does not significantly affect shoot Cd uptake per plant by S. plumbizincicola with appropriate planting density. Above all, using a combined strategy of intercropping with the hyperaccumulator and Al-tolerant crop with the application of soil amendment to alleviate Al toxicity will not significantly decrease soil Cd availability and plant Cd uptake, thus can realize remediation and crop production simultaneously in Al-stressed soils.