摘要:种植单一的超富集植物修复重金属污染土壤，不但中断农业生产导致经济收益降低，而且因生物量较低、修复周期长等诸多弊端导致修复效果不甚理想。间作作为一种传统的农艺管理方式，利用生态位和生物多样性原理等能提高农作物对资源的有效利用，对共植的农作物种类增量提质。在中、轻度污染土壤修复中利用间作体系，通过调控超富集植物与农作物的生长发育，促进超富集植物根系低分子量有机酸（LMWOAs）的分泌，降低其根际土壤pH，增加重金属活性，从而增加超富集植物对重金属的吸收，同时抑制农作物根系LMWOAs的分泌，以减少农作物对重金属的吸收，提高其产量和品质，实现“边生产边修复”，提高土地利用率，并增加经济效益。本文根据近几年来国内外相关文献，综述了间作条件下超富集植物和农作物生物量、生理生化响应、重金属吸收、转运、富集等方面的变化，以及间作对土壤环境质量的影响，并对间作修复重金属污染土壤领域的发展趋势，如超富集植物和农作物间作的信号转导和分子生物学机制、间作体系下两类植物根际微生物类群的差异及其功能机制，以及构建高效间作体系提高重金属污染土壤的修复效率等方面进行了展望。
关键词:超富集植物/
间作/
重金属/
农作物/
土壤修复
Abstract:Phytoextraction is an efficient, novel, economic, green, and low-risk method for metal-polluted soil remediation that harvests metal hyperaccumulators to remove heavy metals from the soil. The cultivation of a single hyperaccumulator for the remediation of heavy metal-polluted soil not only interrupts agricultural production, leading to economic loss, but also results in low remediation efficiency owing to many disadvantages, such as low biomass and long remediation cycle. As a traditional agronomic management method, intercropping can improve the utilization efficiency of resources and increase the quality of co-planted crop species by using the principles of ecological niche and biodiversity. For the remediation of moderately or lightly metal-polluted soil, an intercropping system can be used to increase the concentrations of heavy metals in hyperaccumulators by regulating the growth and development of the hyperaccumulators and crops. Furthermore, the antioxidative ability of the hyperaccumulators and crops is also improved, which decreases the contents of peroxidation products, such as malondialdehyde and reactive oxygen species, in the cell membrane lipids. Intercropping generally enhances low molecular weight organic acid (LMWOA) secretion from the roots of heavy metal hyperaccumulators, decreases the pH value of rhizospheric soil, increases the activity of heavy metals, and consequently promotes heavy metal uptake by hyperaccumulators. However, LMWOA secretion from the crop roots is inhibited, resulting in decreased heavy metal uptake and improved crop yield and quality. Decreased heavy metal uptake by crops reduces the risk to human health, and the increased metal accumulation in hyperaccumulators enhances the removal of heavy metals from the soil. Moreover, the benefits to farmers are not affected or may even increase when using intercropping remediation technology. Therefore, the land utilization rate and economic benefits increase based on the "production while remediated" approach. This study systematically reviewed changes in biomass, physiological and biochemical responses, heavy metal uptake, translocation, and accumulation in hyperaccumulators and crops, as well as the effects of intercropping on soil environmental quality. While many studies examining the effects of intercropping systems on heavy metal hyperaccumulators and crops had focused on growth and development, metal uptake, translocation, accumulation, and physiological and biochemical responses to heavy metal stress, little information was available on the underlying molecular mechanisms of the physiological and biochemical processes. Additionally, the effects of intercropping on the microbial composition of the rhizosphere of heavy metal hyperaccumulators and crops and the related ecological implications and main function mechanisms remained unclear. From these unsolved questions, future perspectives in this field, such as the signal transduction and molecular mechanisms of the intercropping system of hyperaccumulators and crops, the different and functional mechanisms of rhizosphere microorganisms of two plants, and how to construct an efficient intercropping system to improve the remediation efficiency of heavy metal-polluted soil, were also proposed.
Key words:Hyperaccumulator/
Intercropping/
Heavy metals/
Crops/
Soil remediation
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