Browsing by Subject "Antioxidative enzymes"

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Open Access
Heat acelimation and chemical pre-treatments induccd thermotolerancc in chickpea
(University of North Bengal, 2009-03) Tongden, C; Chakraborty, U
Induced heat-tolerance triggered by heat acclimation treatment and foliar application of salicylic acid and abscisic acid were evaluated in three different genotypes of chickpea (Cicer arietinum L.) distinctly differing in their sensitivity to heat stress. Seedlings pre-treated with 100uM salicylic acid (SA) and 50 uM abscisic acid (ABA) showed improved heat tolerance to a lethal temperature of 46°C than the untreated control seedlings. Heat stress increased lipid peroxidation of membranes and reduced plant survival. Protein and proline contents increased significantly in pre-treated seedlings. Cell membrane stability also increased remarkably in pre-treated seedlings of all three genotypes. Changes in activities of antioxidative enzymes like peroxidase, ascorbate peroxidase in pre-treated seedlings revealed increase in enzymatic activities which declined sharply at lethal temperuturc. Quantum of increase in enzymatic activity was however higher in thermotolerant genotype in comparison to heat susceptible genotype. Thermotolerant genotype also exhibited constitutively higher antioxidative activities. Catalase activity, in contrast, showed a significant decrease in its activity in pre-treated seedlings following exposure to lethal temperature. These results indicate that heat acclimation treatment and application of SA and ABA show great potential in inducing heat tolerance in chickpea seedlings and these can be further analyzed to understand their role in thermoprotection.
Open Access
ROS production, H2O2 detection and biochemical characterization of water stressed wheat (Triticum aestivum L.) varieties
(University of North Bengal, 2012-03) Pradhan, B.; Chakraborty, U.
One month old plant of four varieties (MW, KD, GY and GN) of wheat (Triticum aestivum L.) was taken and subjected to water stress for 3, 6 and 9 days. RWC was found to be higher in case of GY and KD when compared to MW and GY. There was an initial enhancement in the activities of all five tested antioxidative enzymes- peroxidase, ascorbate peroxidase, catalase, glutathione reductase and superoxide dismutase in K and GN varieties, while in MW and GY, the activity of catalase and superoxide dismutase showed a decline at all periods of water stress. Peroxidase and glutathione reductase activities increased even on 9th day of stress in K and GN, but all other activities showed a decline after 3 days of stress. The accumulation of H202, showed an increase with increasing days of water stress but in K and GN there was a decline during prolonged water stress. Lipid peroxidation increased significantly which was higher in case of MW and GY. With increase in the duration of water stress proline, phenol and ascorbate content increased. Higher values of MSI and total antioxidant were observed in the cultivar KD and GY with increase in the severity of water stress than in MW and GY. After an initial enhancement the content of carotenoid increased followed by a decline. Total chlorophylls showed a general decline during water stress, but the ratio of chla/b showed an initial increase in the 3rd day of water stress which declined during the latter stages of water stress. Results of the present study indicate that two of the varieties- MW and GY are susceptible to water stress, while the other two-K and GN is tolerant.