Effect of brassinosteroids on nickel Induced changes in vigna radiata

Abstract

Abstract of the thesis, submitted to Aligarh Muslim University, Aligarh, India, for the degree of Doctor of Philosophy in Botany, in the year 2011. Five pot experiments were conducted, during 2008-2010 to elucidate the effect of brassinosteroids on nickel induced changes in Vigna radiata L. Wilczek. Nickel was administered in soil whereas; brassinosteroids were applied as pre-sowing seed soaking treatment or to the foliage. The salient features of each of the five experiments are mentioned below. Experiment 1 The surface sterilized seeds of mung bean (Vigna radiata L.) Wilczek cv. T-44, SML-668, K-851, LML-613, and PDM-139 were inoculated with a uniform layer of Rhizobium sp. The coated seeds were sown in earthen pots (25and#61620; 25 cm) filled with sandy loam soil and farmyard manure mixed in the ratio of 6:1. The Ni was administered through soil (0, 50, 100, or 150 mg kg-1) in the form of NiCl2. Thinning was done 7 d after sowing (DAS), leaving three plants per pot where five pots were maintained per treatment. The plant samples were collected at 30 DAS to assess various growth, photosynthetic, biochemical attributes. All the varieties showed significantly different response to various concentrations of the metal. The varieties T-44, SML-668 and K-851 exhibited lesser damage in response to different levels (0, 50, 100, or 150 mg kg-1) of Ni. The highest level (150 mg kg-1) of Ni generated maximum damage. The varieties PDM-139, LML-613 and K-851 showed less resistance against higher level (150 mg kg-1) of metal. The varieties T-44 and SML-668 found least and moderately affected respectively whereas PDM-139 experienced maximum damage at 150 mg kg-1 of Ni. Moreover, PDM-139 was found most sensitive against metal stress. All the parameters except the activity of antioxidant enzymes, electrolyte leakage and proline content in all the varieties showed a linear decrease as the level of the metal in the soil increased (0, 50, 100, or 150 mg kg-1).