GLDA对狼尾草镉吸收、富集及转运能力的影响

Effects of GLDA on cadmium absorption,accumulation and translocation ability of Pennisetum alopecuroides

  • 摘要: 【目的】探究可降解螯合剂谷氨酸二乙酸四钠(GLDA)以不同浓度施加时,对狼尾草镉(Cd)吸收、富集及转运的影响,为充分利用螯合剂与植物联合修复Cd污染的土壤提供科学依据。【方法】以狼尾草为试验材料,采用盆栽试验法,分析不同浓度GLDA[0(对照)、1、2、3、4和5 mmol/kg]处理下狼尾草生长特性、生理指标及狼尾草各部位对Cd的富集量,并进行GLDA浓度与狼尾草理化性质的相关性分析。【结果】与对照相比,随着GLDA浓度的增加,狼尾草株高、根长和总生物量均呈先升高后降低的变化趋势,在GLDA浓度为2 mmol/kg时分别增加8.23%、4.41%和7.75%;狼尾草叶绿素a含量、总叶绿素含量和叶绿素a/b也呈先升高后降低的变化趋势,在GLDA浓度为2 mmol/kg时达最大值,分别为对照的1.16、1.09和1.19倍。在GLDA处理下狼尾草富集系数(BCF)与对照相比明显升高且表现为根>叶>茎;在GLDA浓度为2 mmol/kg时,狼尾草转运系数(TF)高于1.00,植物修复系数(PRF)达最大值,为1.93。相关分析表明,螯合剂GLDA处理浓度与狼尾草株高、叶绿素含量、地上部生物量及地下部生物量呈极显著负相关(P<0.01,下同),而与地下部Cd含量呈极显著正相关。【结论】低浓度GLDA可通过促进狼尾草叶绿素的生成提高光合效率,促进其生长,提高其富集及转运能力,高浓度则抑制狼尾草生长。GLDA对狼尾草修复Cd污染的最适浓度为2 mmol/kg,可显著提升狼尾草修复Cd污染的效率。

     

    Abstract: 【Objective】 The experimental objective was to explore the effects of the degradable chelating agent GLDA on the absorption, enrichment and transport of Pennisetum alopecuroides cadmium(Cd) when applied at different concentrations, aiming to provide a scientific basis for the full use of chelating agents and plants to repair Cd-contaminated soil.【Method】 P. alopecuroides was used as experimental material, and pot experiment was conducted to study the effects of different molar mass concentrations of GLDA0(control), 1, 2, 3, 4, 5 mmol/kgon the growth index, physiological index, the concentration of Cd in each part of P. alopecuroides. The correlation between GLDA concentration and the physicochemical properties of P. alopecuroides was analyzed.【Result】 The results showed that compared with the control, the plant height, root length and total biomass of P. alopecuroides increased first and then decreased with the increase of GLDA molar mass concentration, the plant height increased 8.23%, the root length increased 4.41% and the total biomass increased 7.75% with GLDA 2 mmol/kg. The chlorophyll a, total chlorophyll and chlorophyll a/b of P. alopecuroides increased firstly and then decreased, and reached the maximum value with GLDA 2 mmol/kg, which were 1.16, 1.09 and 1.19 times of those of the control treatment. Compared with the control, the bioconcentration factors(BCF) of P. alopecuroides under GLDA treatment increased and showed the order of root>leaf>stem. When the molar concentration of GLDA was 2 mmol/kg, translocation factor(TF) >1.00, the maximum value of PRF was 1.93. Correlation analysis showed that the concentration of GLDA was significantly negatively correlated with plant height, chlorophyll, aboveground biomass and underground biomass of P. alopecuroides(P<0.01, the same below), but positively correlated with underground Cd content.【Conclusion】 Comprehensive analysis showed that low concentration of GLDA can improve photosynthetic ef-ficiency, promote the growth of P. alopecuroides and increase its enrichment and transport capacity by promoting the production of chlorophyll, while high concentration can inhibit the growth of P. alopecuroides. The optimum molar mass concentration of GLDA for P. alopecuroides to remediate cadmium pollution is 2 mmol/kg, which can significantly improve the remediation efficiency of cadmium pollution.

     

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