Singh Suruchi, Mishra Shweta, Kumari Rima, Agrawal S B
Ecology Research Circle, Department of Botany, Banaras Hindu University, Varanasi-221 005, India.
J Environ Biol. 2009 Sep;30(5):677-84.
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.
紫外线辐射（UV）虽然有害，但却是陆地生态系统的一个重要且不可避免的组成部分，自植物从水生栖息地迁移到陆地栖息地以来，它们就一直暴露在这种辐射之下。受污染土壤中入射的UV-B辐射和重金属含量是重大的环境威胁，通过产生活性氧影响植物的代谢功能。植物已经进化出机制来对抗这些活性自由基，并修复由UV-B和重金属造成的损害。本研究描述了补充UV-B（sUV-B）和镍（Ni）单独及联合作用对豌豆（Pisum sativum L.）植株光合色素、黄酮类化合物、酶促和非酶促抗氧化剂、代谢物及脂质过氧化的影响。与对照相比，两种胁迫单独及联合作用均导致光合色素、抗坏血酸、蛋白质和过氧化氢酶（CAT）活性降低，而黄酮类化合物、酚类、脯氨酸和硫醇含量、超氧化物歧化酶（SOD）和过氧化物酶（POX）活性以及脂质过氧化（LPO）则呈现相反趋势。然而，与其他处理相比，在单独暴露于sUV-B时黄酮类化合物显著增加。LPO增加81%表明在两种胁迫条件下均产生活性氧。sUV-B和Ni联合作用具有协同效应，使CAT活性提高51.6%，对SOD活性具有累加效应，增加16.4%，而其他参数则显示两种胁迫具有拮抗作用。
