Efficient reduction of Cr(Ⅵ)by guava(Psidium guajava)leaf extract and its mitigation effect on Cr toxicity in rice seedlings  

作　　者：Maodi Ran Yongqing Lu Yanzhen Ren Li He Jiaokun Li 

机构地区：[1]School of Minerals Processing and Bioengineering,Central South University,Changsha 410083,China

出　　处：《Journal of Environmental Sciences》2024年第7期1-15,共15页环境科学学报（英文版）

基　　金：supported by the Natural Science Foundation of Hunan Province of China(No.2019JJ40361)。

摘　　要：Hexavalent chromium(Cr(Ⅵ))is a toxic element that has negative impacts on crop growth and yield.Using plant extracts to convert toxic Cr(Ⅵ)into less toxic Cr(Ⅲ)may be a more favorable option compared to chemical reducing agents.In this study,the potential effects and mechanisms of using an aqueous extract of Psidium guajava L.leaves(AEP)in reducing Cr(Ⅵ)toxicity in rice were comprehensively studied.Firstly,the reducing power of AEP for Cr(Ⅵ)was confirmed by the cyclic voltammetry combined with X-ray photoelectron spectroscopy(XPS)assays.The highest Cr(Ⅵ)reduction efficiency reached approximately 78%under 1.5mg gallic acid equivalent(GAE)/mL of AEP and 10 mg/L Cr(Ⅵ)condition.Additionally,Cr(Ⅵ)stress had a significant inhibitory effect on rice growth.However,the exogenous application of AEP alleviated the growth inhibition and oxidative damage of rice under Cr(Ⅵ)stress by increasing the activity and level of enzymatic and non-enzymatic antioxidants.Furthermore,the addition of AEP restored the ultrastructure of root cells,promoted Cr adsorption onto root cell walls,and limited the translocation Cr to shoots.In shoots,AEP application also triggered the expression of specific genes involved in Cr defense and detoxification response,including photosynthesis pathways,antioxidant systems,flavonoids biosynthesis,and plant hormone signal transduction.These results suggest that AEP is an efficient reduction agent for Cr(Ⅵ),and exogenous application of AEP may be a promising strategy to mitigate the harm of Cr(Ⅵ)on rice,ultimately contributing to improved crop yield in Crcontaminated environments.

关 键 词：Hexavalent chromium Plant extract REDUCTION Rice plants MECHANISMS 

分 类 号：X173[环境科学与工程—环境科学] S511[农业科学—作物学]