{"title":"Lead accumulation and concomitant reactive oxygen species (ROS) scavenging in Robinia pseudoacacia are dependent on nitrogen nutrition.","authors":"Zhuyuan Xia, Caixin Xue, Rui Liu, Qiuling Hui, Bin Hu, Heinz Rennenberg","doi":"10.1016/j.plaphy.2024.109388","DOIUrl":null,"url":null,"abstract":"<p><p>Heavy metal pollution combined with nitrogen (N) limitation is a major factor preventing revegetation of contaminated land. Woody N<sub>2</sub>-fixing legumes are a natural choice for phytoremediation. However, the physiological responses of woody legumes to lead (Pb) with low N exposure are currently unknown. In the present study, a common Robinia cultivar from Northeast China, inoculated and non-inoculated with rhizobia, was exposed to -Pb or + Pb at moderate (norN) or low N application (lowN). Our results showed that without inoculation, independent of N application, Pb taken up by the roots was allocated to the shoot and inhibited photosynthesis and biomass production. In non-inoculated Robinia, Pb-mediated oxidative stress resulted in reduced H<sub>2</sub>O<sub>2</sub> scavenging as indicated by increased ascorbate peroxidase (APX) activity in the leaves and proline contents in the roots, independent of N application. Combined lowN∗Pb exposure significantly increased malondialdehyde (MDA) contents in roots and leaves and enhanced APX and dehydroascorbate reductase activities in leaves compared to individual Pb exposure. Rhizobia inoculation raised the abundance of nodules and promoted Pb uptake by roots. Under Pb exposure, inoculation with rhizobia reduced MDA contents, increased proline contents in leaves and roots and enhanced activity of nitrate reductase in the leaves, independent of N application. Under Pb exposure, nitrogenase activity of inoculated Robinia under low- and norN application were similar indicating that enhanced of N<sub>2</sub>-fixation at lowN was counteracted by Pb exposure. These results show that inoculation of Robinia with rhizobia can alleviate Pb toxicity at combined lowN and Pb exposure by reducing oxidative stress.</p>","PeriodicalId":20234,"journal":{"name":"Plant Physiology and Biochemistry","volume":"219 ","pages":"109388"},"PeriodicalIF":6.1000,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Plant Physiology and Biochemistry","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1016/j.plaphy.2024.109388","RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PLANT SCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
Heavy metal pollution combined with nitrogen (N) limitation is a major factor preventing revegetation of contaminated land. Woody N2-fixing legumes are a natural choice for phytoremediation. However, the physiological responses of woody legumes to lead (Pb) with low N exposure are currently unknown. In the present study, a common Robinia cultivar from Northeast China, inoculated and non-inoculated with rhizobia, was exposed to -Pb or + Pb at moderate (norN) or low N application (lowN). Our results showed that without inoculation, independent of N application, Pb taken up by the roots was allocated to the shoot and inhibited photosynthesis and biomass production. In non-inoculated Robinia, Pb-mediated oxidative stress resulted in reduced H2O2 scavenging as indicated by increased ascorbate peroxidase (APX) activity in the leaves and proline contents in the roots, independent of N application. Combined lowN∗Pb exposure significantly increased malondialdehyde (MDA) contents in roots and leaves and enhanced APX and dehydroascorbate reductase activities in leaves compared to individual Pb exposure. Rhizobia inoculation raised the abundance of nodules and promoted Pb uptake by roots. Under Pb exposure, inoculation with rhizobia reduced MDA contents, increased proline contents in leaves and roots and enhanced activity of nitrate reductase in the leaves, independent of N application. Under Pb exposure, nitrogenase activity of inoculated Robinia under low- and norN application were similar indicating that enhanced of N2-fixation at lowN was counteracted by Pb exposure. These results show that inoculation of Robinia with rhizobia can alleviate Pb toxicity at combined lowN and Pb exposure by reducing oxidative stress.
期刊介绍:
Plant Physiology and Biochemistry publishes original theoretical, experimental and technical contributions in the various fields of plant physiology (biochemistry, physiology, structure, genetics, plant-microbe interactions, etc.) at diverse levels of integration (molecular, subcellular, cellular, organ, whole plant, environmental). Opinions expressed in the journal are the sole responsibility of the authors and publication does not imply the editors'' agreement.
Manuscripts describing molecular-genetic and/or gene expression data that are not integrated with biochemical analysis and/or actual measurements of plant physiological processes are not suitable for PPB. Also "Omics" studies (transcriptomics, proteomics, metabolomics, etc.) reporting descriptive analysis without an element of functional validation assays, will not be considered. Similarly, applied agronomic or phytochemical studies that generate no new, fundamental insights in plant physiological and/or biochemical processes are not suitable for publication in PPB.
Plant Physiology and Biochemistry publishes several types of articles: Reviews, Papers and Short Papers. Articles for Reviews are either invited by the editor or proposed by the authors for the editor''s prior agreement. Reviews should not exceed 40 typewritten pages and Short Papers no more than approximately 8 typewritten pages. The fundamental character of Plant Physiology and Biochemistry remains that of a journal for original results.