ALA协同PASP强化伴矿景天提取土壤重金属Cd的研究

Study on Polyaspartic Acid(PASP)and 5-Aminovaleric Acid(ALA)to Enhance Extraction of Heavy Metal Cd from Soil by Sedum plumbizincicola

[目的]探究5-氨基酮戊酸(ALA)协同螯合剂聚天冬氨酸(PASP)增强伴矿景天提取土壤Cd的最佳条件。[方法]通过盆栽试验,伴矿景天种植于Cd污染土壤(总Cd0.68 mg/kg)中,且在移栽45 d后开始浇灌不同添加浓度的PASP(3、6、12 g/kg,分别等分为3次使用,2~3次使用的间隔时间分别为15、30 d);ALA(25 mmol/L)于PASP处理后第3天灌施,按不同的施用次数(0、1、2、3)处理,间隔时间同PASP处理。分析伴矿景茎长、地上部生物量、Cd含量和Cd提取量,建立各指标之间的相关性并拟合生物量和Cd提取量与PASP施用量、ALA使用次数的预测模型。[结果]ALA协同中等剂量(6 g/kg)PASP连续3次的施用能显著提高伴矿景天茎长、地上部生物量、地上部分Cd含量和Cd提取量;线性回归显示PASP施用量和ALA施用次数是地上部分生物量和Cd提取量的关键影响因子;地上部分Cd提取量在PASP施用量为6 g/kg协同ALA 3次连续使用时达到最大,为1.09 g/盆,是CK提取量的2.79倍;地上部分生物量、茎长与ALA施用次数呈显著正相关,而与PASP施用量呈显著负相关。[结论]研究结果揭示了ALA协同PASP在强化伴矿景天提取土壤Cd具有重要意义,且需选择合适的配比和施用次数。

[Objective]To explore the optimal conditions for enhancing the extraction of soil Cd from S.plumbizincicola by synergistic chelating agent polyaspartic acid(PASP)with 5-aminopyruvic acid(ALA).[Method]A pot experiment was conducted to plant S.plumbizincicola in Cd contaminated soil(total Cd 0.68 mg/kg).After 45 d of transplanting,PASP was applied in different doses within 45 days:total application mounts of 3,6 and 12 g/kg(base on a dry soil)were equally divided into 1-3 applications,respectively,and the time intervals of 2-3 applications were 15,30 days.ALA(25 mmol/L)was applied on the third day after each PASP treatment,and treated according to different application times(0,1,2,3).The interval time was the same as that of PASP.The stem length,biomass,Cd content and amount of Cd extracted from aboveground part of S.plumbizincicola were analyzed,in addition to the correlation between the indexes was established,and fitted the prediction model of biomass and Cd extraction amount on PASP application rate and ALA use times.[Result]ALA combined with medium dose(6 g/kg)of PASP for three consecutive times could significantly increase the stem length,aboveground biomass,Cd content and extraction amount of S.plumbizincicola.Linear regression showed that PASP application rate and ALA application times were the key influencing factors of aboveground biomass and Cd extraction amount.The highest value of Cd extracted from aboveground part was 1.09 g/por when applying PASP in 6 mg/kg,which was 2.79 times higher than CK when it was used 3 times in combination with ALA.The aboveground biomass and stem length were significantly positively correlated with the application times of ALA,but negatively correlated with the application amount of PASP.[Conclusion]The results reveal that ALA assisted PASP had important significance in enhancing the extraction of soil cadmium by S.plumbizincicola,and it was necessary to choose the appropriate combination mode.