TY - JOUR
TI - Hexavalent chromium leads to differential hormetic or damaging effects in alfalfa (Medicago sativa L.) plants in a concentration-dependent manner by regulating nitro-oxidative and proline metabolism
AU - Christou, A.
AU - Georgiadou, E.C.
AU - Zissimos, A.M.
AU - Christoforou, I.C.
AU - Christofi, C.
AU - Neocleous, D.
AU - Dalias, P.
AU - Torrado, S.O.C.A.
AU - Argyraki, A.
AU - Fotopoulos, V.
JO - Environmental Pollution
PY - 2020
VL - 267
TODO - null
SP - null
PB - Elsevier Ireland Ltd
SN - 0269-7491
TODO - 10.1016/j.envpol.2020.115379
TODO - Gene expression;  Irrigation;  Plants (botany);  Water, Adaptation response;  Concentration-dependent manners;  Enzymatic activities;  Gene expression levels;  Gene expression patterns;  Growth and development;  Photosynthetic pigments;  Threshold concentrations, Chromium compounds, carotenoid;  catalase;  chlorophyll a;  chlorophyll b;  chromium;  hydrogen peroxide;  nitrate reductase;  nitric oxide;  proline;  pyrroline 5 carboxylate reductase;  reduced nicotinamide adenine dinucleotide dehydrogenase;  superoxide dismutase;  antioxidant;  chromium;  chromium hexavalent ion;  proline, angiosperm;  antioxidant;  biomass;  chromium;  metabolism;  oxidative stress;  physiological response;  pigment;  pollution exposure, alfalfa;  amino acid metabolism;  Article;  biomass production;  concentration (parameter);  controlled study;  environmental exposure;  enzyme activity;  evolutionary adaptation;  gene overexpression;  GST17 gene;  GST7 gene;  hormesis;  irrigation (agriculture);  lipid peroxidation;  metabolic regulation;  ndh gene;  nonhuman;  NR gene;  oxidative stress;  P5CR gene;  P5CS gene;  photosynthesis;  phytotoxicity;  pigmentation;  plant damage;  plant gene;  plant leaf;  plant stress;  alfalfa;  oxidative stress, Medicago sativa, Antioxidants;  Chromium;  Hormesis;  Hydrogen Peroxide;  Medicago sativa;  Oxidative Stress;  Proline
TODO - Chromium has been proven to be extremely phytotoxic. This study explored the impacts of increasing Cr(VI) exposure (up to 10 mg L−1 K2Cr2O7) on the growth and development of alfalfa plants and adaptation responses employed, in an environmentally relevant context. The threshold concentration of K2Cr2O7 in irrigation water beyond which stress responses are initiated is 1 mg L−1. Lower Cr(VI) exposure (0.5 mg L−1 K2Cr2O7) induced hormesis, evident through increased biomass and larger leaves, likely mediated by increased NO content (supported by elevated NR enzymatic activity and overexpression of NR and ndh genes). Elevated Cr(VI) exposure (5 and 10 mg L−1 K2Cr2O7) resulted in reduced biomass and smaller leaves, and lower levels of photosynthetic pigment (10 mg L−1 K2Cr2O7). Higher levels of lipid peroxidation, H2O2 and NO contents in these plants suggested nitro-oxidative stress. Stress responses included increased SOD and CAT enzymatic activities, further supported to some extent by MnSOD, FeSOD, Cu/ZnSOD and CAT transcripts levels. GST7 and GST17 gene expression patterns, as well as proline content, P5CS enzymatic activity and corresponding P5CS and P5CR gene expression levels emphasized the role of proline and GSTs in the adaptation responses. Results highlight the importance of managing Cr(VI) levels in irrigation water. © 2020 Elsevier Ltd
ER -