title: Arsenic accumulation and tolerance in rootless macrophyte Najas indica are mediated through antioxidants, amino acids and phytochelatins.
abstract: Arsenic (As) accumulation and tolerance response of a submerged rootless macrophyte Najas indica were evaluated during arsenate (As(V); 10-250 μM) and arsenite (As(III); 1-50 μM) exposure. Higher As accumulation at As(III) exposure and more tolerance upon As(V) exposure resulted in more toxicity during As(III) stress than As(V), which was evident through measurement of growth parameters and oxidative stress related parameters viz., lipid peroxidation (MDA content), electrical conductivity (EC) and hydrogen peroxide (H2O2) levels. Antioxidant enzymes and various amino acids were more prominent during moderate exposure of As(V), suggesting their possible role in As tolerance and detoxification. Various non-enzymatic antioxidant metabolites viz., ascorbic acid (ASC), glutathione (GSH), non-protein thiols (NPTs) and phytochelatins (PCs) biosynthesis involving phytochelatin synthase (PCS) activity increased more significantly during As(III) stress. However, PCs content seems inadequate in response to As accumulation leading to lower PC-SH:As molar ratio and higher As phytotoxicity during As(III) stress. N. indica may prove useful plant species for phytoremediation purpose in moderately As contaminated water bodies due to high As accumulation and tolerance potential.
authors.affiliation: CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow 226 001, India. Electronic address: tripathi_rd@rediffmail.com.
authors.forename: Rudra Deo
authors.initials: RD
authors.lastname: Tripathi
authors.affiliation: CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow 226 001, India.
authors.forename: Ragini
authors.initials: R
authors.lastname: Singh
authors.affiliation: CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow 226 001, India.
authors.forename: Preeti
authors.initials: P
authors.lastname: Tripathi
authors.affiliation: CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow 226 001, India.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Dwivedi
authors.affiliation: CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow 226 001, India.
authors.forename: Reshu
authors.initials: R
authors.lastname: Chauhan
authors.affiliation: Rice Research Station, Department of Agriculture, Government of West Bengal, Chinsurah, Hooghly 712 102, India.
authors.forename: Bijan
authors.initials: B
authors.lastname: Adhikari
authors.affiliation: CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow 226 001, India.
authors.forename: Prabodh Kumar
authors.initials: PK
authors.lastname: Trivedi
mesh_terms: D035961:Alismatales / Q000187:drug effects* / Q000378:metabolism*; D000596:Amino Acids / Q000378:metabolism*; D019881:Aminoacyltransferases / Q000378:metabolism; D000975:Antioxidants / Q000378:metabolism*; D001151:Arsenic / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity*; D018053:Arsenites / Q000378:metabolism / Q000633:toxicity; D001673:Biodegradation, Environmental; D018384:Oxidative Stress / Q000187:drug effects; D054811:Phytochelatins / Q000096:biosynthesis / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D000596:Amino Acids; D000975:Antioxidants; D018053:Arsenites; D013438:Sulfhydryl Compounds; D014874:Water Pollutants, Chemical; D054811:Phytochelatins; D019881:Aminoacyltransferases; C093784:glutathione gamma-glutamylcysteinyltransferase; C015001:arsenite; D001151:Arsenic
keywords: Amino acid; Antioxidants; Arsenate; Arsenite; Najas indica; Phytochelatin