Activity

Nitrogen (N) is the basis of plant growth and development and, is considered as one of the priming agents to elevate a range of stresses. Plants use solar radiations through photosynthesis, which amasses the assimilatory components of crop yield to meet the global demand for food. Nitrogen is the main regulator in the allocation of photosynthetic apparatus which changes of the photosynthesis (Pn) and quantum yield (Fv/Fm) of the plant. In the present study, dynamics of the photosynthetic establishment, N-dependent relation with chlorophyll fluorescence attributes and Rubisco efficacy was evaluated in low-N tolerant (cv. CR Dhan 311) and low-N sensitive (cv. Rasi) rice cultivars under low-N and optimum-N conditions. There was a decrease in the stored leaf N under low-N condition, resulting in the decreased Pn and Fv/Fm efficiency of the plants through depletion in the activity and content of Rubisco. The Pn and Fv/Fm followed the parallel trend of leaf N content during low-N condition along with depletion of intercellular CO2 concentration and overall conductance under low-N condition. Photosynthetic saturation curve cleared abrupt decrease of effective quantum yield in the low-N sensitive rice cultivar than the low-N tolerant rice. Also, the rapid light curve highlighted the unacclimated regulation of photochemical and non-photochemical quenching in the low-N condition. The low-N sensitive rice cultivar triumphed non-photochemical quenching, whereas the low-N tolerant rice cultivar rose gradually during the light curve. Our study suggested that the quantum yield is the key limitation for photosynthesis in low-N condition. Regulation of Rubisco, photochemical and non-photochemical quenching may help plants to grow under low-N level. © Prof. H.S. Srivastava Foundation for Science and Society 2019.In the present study the potentials of aqueous extracts of the two plants, neem (Azadirachta indica) and Tulsi (Ocimum sanctum) were examined in alleviating arsenic toxicity in rice (Oryza sativa L.) plants grown in hydroponics. Seedlings of rice grown for 8 days in nutrient solution containing 50 μM sodium arsenite showed decline in growth, reduced biomass, altered membrane permeability and increased production of superoxide anion (O2 ·-), H2O2 and hydroxyl radicals (·OH). Increased lipid peroxidation marked by elevated TBARS (thiobarbituric acid reactive substances) level, increased protein carbonylation, alterated levels of ascorbate, glutathione and increased activities of enzymes SOD (superoxide dismutase), CAT (catalase), APX (ascorbate peroxidase) and GPX (glutathione peroxidase) were noted in the seedlings on As treatment. Exogenously added leaf aqueous extracts of Azadirachta indica (0.75 mg mL-1, w/v) and Ocimum sanctum (0.87 mg mL-1, w/v) in the growth medium considerably alleviated As toxicity effects in the seedlings, marked by reduced As uptake, restoration of membrane integrity, reduced production of ROS, lowering oxidative damage and restoring the levels of ascorbate, glutathione and activity levels of antioxidative enzymes. Arsenic uptake in the seedlings declined by 72.5% in roots and 72.8% in shoots, when A. indica extract was present in the As treatment medium whereas with O. sanctum extract, the uptake declined by 67.2% in roots and 70.01% in shoots. Results suggest that both A. indica and O. sanctum aqueous extracts have potentials to alleviate arsenic toxicity in rice plants and that A. indica can serve as better As toxicity alleviator compared to O. sanctum. © Prof. H.S. Srivastava Foundation for Science and Society 2019.The manuscript highlights the role of antioxidants in alleviation of salinity stress in two principal legume crops Cyamopsis tetragonoloba and Vigna radiata of Indian Thar Desert. The study evaluates correlation between the antioxidants of two cultivars in terms of morphological and physiological alterations. Hydroponically acclimatized seedlings of both the crops were subjected to NaCl stress at different concentrations ranges from 10 to 100 mM. After 96 h, the treated legumes were harvested to analyze the cellular homeostasis and salt tolerance mechanism via examining growth, stress parameters, osmoprotectants and enzymatic antioxidants. Differential response in the antioxidants activity was observed in crops. Equal contribution of antioxidants in mitigation of salinity stress was recorded in C. tetragonoloba while V. radiata shows greater tolerance by accumulating greater amount of proline which is approximately 2.72 folds higher than C. tetragonoloba. Moreover, the NR and HO1 activities in V. radiata were recorded to be 2.76 and 1.55 folds respectively which is 1.2 times higher in comparison to C. tetragonoloba. The detrimental effect of NaCl in terms of MDA content was also higher in V. radiata which concluded that V. radiata is more reactive towards salinity stress than C. tetragonoloba. The study is significant as this is the first report illustrating the sensitivity and tolerance level of NaCl in legumes of Thar Desert. © Prof. H.S. Srivastava Foundation for Science and Society 2019.The present study provides the first comparative fatty acid profiling of the three Indian seabuckthorn species, collected from varying altitudes (2900-4300 masl) of Trans-Himalayas (Hippophae rhamnoides, H. Cyclosporin A manufacturer tibetana) and Sikkim Himalayas (H. salicifolia) regions. Gas chromatography-mass spectrometry analysis showed variability in fatty acid composition of different seabuckthorn populations. Sikkim populations showed higher (1.28-1.6 folds) palmitic acid than Trans-Himalayan populations which possess higher linoleic (1.3-1.5 folds) and linolenic (1.6-1.8 folds) acids. Interestingly, a strong altitudinal gradient associated positive correlation was observed with the degree of unsaturation and PUFA content while negative correlation was observed with saturated fatty acids content of different seabuckthorn populations. H. salicifolia collected from Sikkim showed healthy ω-6ω-3 ratio (closer to 11) of functional lipids exhibiting its better nutraceutical potential than other commonly used seed oils. Interestingly, H.