Prof. A. HemantaranjanTanu Priya2017-01-192017-01-192016Priya, T. 2016. Effect of brassinosteroids (brassinolide) on morpho- physiological, biochemical and antioxidant enzymes activity on field pea (Pisum sativum L.) genotypes under cadmium stress. M. Sc. (Ag.) Thesis, Department of Plant Physiology, Institute of Agricultural Sciences, BHU, Varanasi.http://krishikosh.egranth.ac.in/handle/1/97180The present investigation was carried out in soil culture by inducing cadmium toxicity with CaCr, @ 50 mM and Cd Cb @ 100 mM in the Department of Physiology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi. There were six treatments including control as follows, Control T0: [without CaCr, and brassinolide]; T1 [Brassinolide 0.05 mM]; T2 [CdCh 50 mM]; T3 [CdCb 100 mM]; T4 [Brassinolide 0.05 mM + CaCi, 50 mM]; T5 [Brassinolide 0.05 mM+ CaCi, 100 mM]. The experiment was conducted in factorial randomized block design with six individual treatments and each treatment was replicated three times. Observations were made on certain morpho-physiological, biochemical, antioxidant enzymes activity, viz., germination percentage, length of shoot, length of root, number of leaves per plant, leaf area, dry matter production of shoot, dry matter production of root, total dry matter production, root: shoot ratio, chlorophyll a, chlorophyll b, total chlorophyll, nitrate reductase activity, proline content, protein content, sugar content, hydrogen peroxide, catalase, ascorbate peroxidase, malondialdehyde content and superoxide dismutase activity. The observation for germination percentage was recorded at 10 DAS in growth chamber. However the observations on morpho-physiological parameters were taken at 40, 60 and 80 DAS in the net house. In present experiment with increase in induced cadmium stress, a significant enhancement in CAT activity with respect to control in the plants was observed. A similar trend was also observed after CdCh stress imposition, the NR activity in treated seedlings was drastically decreased with respect to control. The combined application of BL along with CdCh in pea plants altered the activities of antioxidant enzymes in comparison to CdCl, treated alone. During the combined application of 50 mM CdCl- with 0.05 mM BL, the increment in CAT activity was increased several times over Cd'Cl , treated alone, while in case of the combined application of 100 mM CdCh with 0.05 mM BL, the CAT activity was increased over CdCl-, treated but by relatively lesser margin over as compared to 50 mM CdCh with 0.05 mM BL. In case of the combined application of 50 mM CdCh with 0.05 mM BL the increment in hydrogen peroxide activity was found over CdCh treated alone. The increased accumulation of pro line resulted in the increased capacity of Cd stress in the present experiment, minimum in control plants. Keeping in view the facts regarding brassinosteroids (BRs ), this may be concluded that brassinolide (BL) has positive effects on morpho-physiological, biochemical and antioxidant enzymes activity under induced cadmium stress in pea. Therefore, brassinolide could be utilized effectively for combating cadmium stress.enThesis