镉污染土壤伴矿景天的萃取强化-螯合剂和植物激素的叶面调控

为提高Cd超富集植物伴矿景天(Sedum plumbizicola)的植物萃取能力,采用盆栽试验研究螯合剂乙二胺四乙酸(EDTA)和植物激素脱落酸(ABA)单独和联合作用的叶面调控对伴矿景天生长和Cd吸收转运的影响,并通过大田试验进行验证。结果表明:盆栽试验叶面喷施EDTA、ABA均能提高伴矿景天对Cd的转运,地下部至地上部的Cd转运系数为EDTA＞ABA,但叶面EDTA处理对生长旺盛期伴矿景天的生长有抑制。伴矿景天各部位Cd富集浓度差异很大,呈现新叶＞地下部＞茎＞老叶,新叶中Cd浓度是老叶的3.6~5.4倍,且主要富集在细胞壁和细胞器中,占总富集量的88%~94%。EDTA处理新叶细胞器中Cd浓度剧增,ABA处理新叶细胞壁中Cd浓度增加,ABA和EDTA联合使用可以缓解EDTA对生长的抑制,且更有利于Cd从根系向地上部转运。大田小区试验叶面诱导强化伴矿景天Cd萃取是可行的,ABA和EDTA联合处理显著增加伴矿景天总Cd积累量,增幅达到37.87%。研究结果为伴矿景天修复Cd污染土壤提供理论指导。

An Enhanced Phytoextraction of Sedum plumbizicola in Cd Contaminated Soil-the Foliar Application of Chelating Agent and Phytohormones

To improve the phytoextraction capacity of Cd hyperaccumulotor Sedum plumbizicola, pot experiments were done to investigate the effects of the chelating agent ethylenediaminetetraacetic acid (EDTA) and the plant hormone abscisic acid (ABA) on the growth and Cd transport of Sedum plumbizicola and verified by field experiment. The results of pot experiments showed that the foliar spraying EDTA and ABA could promote the transport of Cd by Sedum plumbizicola, and the transport coefficient of Cd from underground part to aboveground part was EDTA > ABA. But foliar application of EDTA inhibit the growth of Sedum plumbizicola. The concentrations of Cd in different tissues of Sedum plumbizicola varied greatly, with new leaves > roots > stems > old leaves. The concentration of Cd in the new leaves was 3.6~5.4 times of that in old leaves, and the majority was enriched in the cell wall and organelle fraction, accounting for 88%~94% of the total. EDTA treatment caused a sharp increase in the proportion of Cd allocated to organelles, and ABA, on the contrary, greatly increased the proportion of Cd distributed in the cell wall of new leaves. The combination of ABA and EDTA could alleviate the inhibition of growth by EDTA, and could be conducive to the Cd transportation from root to aboveground.. Field experiment verified that the enhanced phytoextraction of Sedum plumbizicola in Cd contaminated soil based on the foliar application of ABA and EDTA was feasible. The combination of ABA and EDTA treatment significantly increased the total Cd accumulation of Sedum plumbizicola by 37.87%. The results provide theoretical guidance for strengthening the remediation of Cd contaminated soil by Sedum plumbizicola.