title: Oxygen toxicity and antioxidative responses in arsenic stressed Helianthus annuus L. seedlings against UV-B.
abstract: In order to know the impact of elevated level of UV-B on arsenic stressed Helianthus annuus L. var. DRSF-113 plants, certain physiological (growth - root and shoot lengths, their fresh masses and leaf area; photosynthetic competence and respiration) and biochemical parameters (pigments - Chl a and b, Car, anthocyanin and flavonoids; reactive oxygen species - superoxide radicals, H2O2; reactive carbonyl group, electrolyte leakage; antioxidants - superoxide dismutase, peroxidise, catalase, glutathione-S-transferase, proline) of their seedlings were analysed under the simultaneous exposures of two arsenic doses (6mgkg-1soil, As1; and 12mgkg-1soil, As2) and two UV-B doses (1.2kJm-2d-1, UV-B1; and 3.6kJm-2d-1, UV-B2). As1and As2alone declined all the studied growth parameters - along with photosynthetic pigments which were further aggravated after the simultaneous exposures of predefined levels of UV-B. Each As exposure was accompanied by significant accumulation of As in root, shoot and leaves and was substantiated by simultaneous exposures of UV-B doses which manifested into suppressed growth, decreased chlorophyll contents and photosynthesis. In similar conditions, other photo-shielding pigments, viz. carotenoids, anthocyanin and flavonoids along with respiration and oxidative stress markers such as O2•¯, H2O2; and indicators of cell membrane damage like MDA (malondialdehyde), RCG (reactive carbonyl group), electrolyte leakage were enhanced by As, and became more pronounced after the simultaneous exposures of UV-B doses. As doses stimulated the activities of SOD, POD, CAT, GST and Pro which got further accelerated after the simultaneous exposures of UV-B doses.
authors: Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of Allahabad (A Central University of India), Allahabad 211 002, India.
authors: Geeta
authors: G
authors: Yadav
authors: Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of Allahabad (A Central University of India), Allahabad 211 002, India; Pt. Ravi Shankar Tripathi Government Degree College, Bhaiyathan, Surajpur 497 231, Chhattisgarh, India. Electronic address: prabhatsrivastava.au@gmail.com.
authors: Prabhat Kumar
authors: PK
authors: Srivastava
authors: Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of Allahabad (A Central University of India), Allahabad 211 002, India.
authors: Parul
authors: P
authors: Parihar
authors: Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of Allahabad (A Central University of India), Allahabad 211 002, India.
authors: Sanjesh
authors: S
authors: Tiwari
authors: Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of Allahabad (A Central University of India), Allahabad 211 002, India. Electronic address: profsmprasad@gmail.com.
authors: Sheo Mohan
authors: SM
authors: Prasad
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D001151:Arsenic / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D006368:Helianthus / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects; D010100:Oxygen / Q000633:toxicity*; D013312:Stress, Physiological; D014466:Ultraviolet Rays
chemical_list: D000975:Antioxidants; D001151:Arsenic; D010100:Oxygen
keywords: Antioxidants; Arsenic; Helianthus annuus; Oxidative damage; Oxygen toxicity UV-B