Effect of UV - B Radiation on Plants

Abstract

UV-B is a biologically active portion of ultraviolet light that has significant effects on the development and metabolism of plants. Despite it being a small component of sunlight, it can be damaging to many higher plant species and can cause mutations, damage to genetic material, reductions in photosynthetic activity, lower electron transfer rates, smaller shoot biomass, decreased leaf size, leaf number, and reductions in chlorophyll content, biomass and ultimately plant productivity. At the cellular level, it initially causes oxidative stress by increasing the reactive oxygen species (ROS) levels, which subsequently damage to proteins, lipids, and other biomolecules, thus, compromising the functionality and integrity of enzymes and cell membranes. Exposure to UV-B is obligatory for higher plants because of the need to maximize light capture for photosynthesis.UV-B radiation significantly increases enzymatic and non enzymatic antioxidants, cytosolutes (proline,sugars glycine betane), secondary metabolites and bioactive compounds for survival of plants. Plant Growth Regulators (PGRs) play important role in mitigating adverse effects of the radiation in plants. Plants have specific signaling pathway that regulate the protective gene expression responses to UV-B required for plant survival in sunlight. Recently, genetic engineering has contributed enormously to the develop transgenic plants . The identification of UV B stress-responsive genes and their subsequent introgression or overexpression within sensitive crop species are now being widely carried out by plant scientists.