Light intensity alters the extent of arsenic toxicity in Helianthus annuus L. seedlings.
The present study is aimed at assessing the extent of arsenic (As) toxicity under three different light intensities-optimum (400 μmole photon m(-2) s(-1)), sub-optimum (225 μmole photon m(-2) s(-1)), and low (75 μmole photon m(-2) s(-1))-exposed to Helianthus annuus L. var. DRSF-113 seedlings by examining various physiological and biochemical parameters. Irrespective of the light intensities under which H. annuus L. seedlings were grown, there was an As dose (low, i.e., 6 mg kg(-1) soil, As1; and high, i.e., 12 mg kg(-1) soil, As2)-dependent decrease in all the growth parameters, viz., fresh mass, shoot length, and root length. Optimum light-grown seedlings exhibited better growth performance than the sub-optimum and low light-grown seedlings; however, low light-grown plants had maximum root and shoot lengths. Accumulation of As in the plant tissues depended upon its concentration used, proximity of the plant tissue, and intensity of the light. Greater intensity of light allowed greater assimilation of photosynthates accompanied by more uptake of nutrients along with As from the medium. The levels of chlorophyll a, b, and carotenoids declined with increasing concentrations of As. Seedlings acquired maximum Chl a and b under optimum light which were more compatible to face As1 and As2 doses of As, also evident from the overall status of enzymatic (SOD, POD, CAT, and GST) and non-enzymatic antioxidant (Pro).
Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of Allahabad (A Central University of India), Allahabad, 211 002, India, geetayadav_au@yahoo.com.
Geeta
G
Yadav
Prabhat Kumar
PK
Srivastava
Vijay Pratap
VP
Singh
Sheo Mohan
SM
Prasad
D001151:Arsenic / Q000633:toxicity*; D018533:Biomass; D002338:Carotenoids / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D005982:Glutathione Transferase / Q000378:metabolism; D006368:Helianthus / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D008027:Light; D008315:Malondialdehyde / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects / Q000528:radiation effects; D009195:Peroxidase / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects / Q000528:radiation effects; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects; D018547:Plant Stems / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects; D011392:Proline / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development* / Q000528:radiation effects; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism
D013481:Superoxides; D002734:Chlorophyll; D002338:Carotenoids; D008315:Malondialdehyde; C037184:chlorophyll b; D011392:Proline; D006861:Hydrogen Peroxide; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase; D001151:Arsenic; D000077194:Chlorophyll A