Journal of Environmental Biology

Response of ultraviolet-B and nickel on pigments, metabolites

and antioxidants of Pisum sativum L.

 

Suruchi Singh, Shweta Mishra, Rima Kumari and S.B. Agrawal*

Ecology Research Circle, Department of Botany, Banaras Hindu University, Varanasi - 221 005, India

(Received: August 03, 2008; Revised received: September 23, 2008; Accepted: September 25, 2008)

 

Abstract: Ultraviolet radiation (UV) though harmful but is an important and unavoidable component of terrestrial ecosystem to which plants have been exposed since their migration from aquatic to land habitat. Incoming UV-B radiation and heavy metals abundance in contaminated soils are significant environmental threat affecting metabolic functions of plants through generation of reactive oxygen species. Plants have evolved mechanisms to counteract these reactive radicals and to repair the damage caused by UV-B and heavy metals. This study describes the impact of supplemental UV-B (sUV-B) and nickel (Ni) singly and in combination on photosynthetic pigments, flavonoids, enzymatic and non-enzymatic antioxidants, metabolites and lipid peroxidation of Pisum sativum L. (pea) plants. Compared to the controls, both the stresses individually and in combination led to reductions in photosynthetic pigments, ascorbic acid, protein and catalase (CAT) activity, whereas a reverse trend was observed for flavonoids, phenol, proline and thiol contents, superoxide dismutase (SOD) and peroxidase (POX) activities and lipid peroxidation (LPO). However, flavonoids increased significantly under individual exposure of sUV-B as compared to other treatments. An increase of LPO by 81% indicated the generation of reactive oxygen species under both the stress conditions. sUV-B and Ni in combination acted synergistically with stimulation of CAT activity by 51.6% , additively on SOD activity with increase of 16.4%,? while other parameters showed? antagonistic action of both the stresses.

Key words: sUV-B, Ni, Pigments, Lipid peroxidation, Antioxidants, Pisum sativum

 

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