Browsing by Author "Parida, Asish Kumar"

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    Impacts of Climate Change on Asian Mangrove Forests
    (2014-02-06) Parida, Asish Kumar; Tiwari, Vivekanand; Bhavanath, Jha
    Mangroves are woody trees and shrubs which thrive in the inhospitable zone between land and sea along the tropical and subtropical coasts of the globe. Mangroves have made significant contributions to the economical status of the coastal communities of tropical regions for centuries, affording a large number of goods and services such aswood and timber production, salt production, support for commercial and subsistence fisheries, protection of shoreline from cyclones and typhoons and controlling coastal erosion. It has been estimated that the total mangrove area of the world was 137,760 km2 in 2000, and Asia occupies the largest mangrove covering area in the world. The mangrove forests of Asia are currently threatened by many human activities. Besides the overexploitation of mangrove ecosystems by human activities, climate changes pose serious impacts on Asian mangrove forests. The recent studies that have focused on various climate change components affecting the mangrove forests will be discussed in this chapter with special emphasis on Asian mangrove forests. The changes in the temperature, atmospheric CO2 concentration, precipitation, storms, ocean circulation patterns, hydrology (flows of tidal and fresh
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    Inductive responses of some organic metabolites for osmotic homeostasis in peanut (Arachis hypogaea L.) seedlings during salt stress
    (2014-02-06) Parida, Asish Kumar; Jha, Bhavanath
    The salt tolerance of peanut (Arachis hypogaea L.) seedlings was evaluated by analyzing growth, nutrient uptake, electrolyte leakage, lipid peroxidation and alterations in levels of some organic metabolites under NaCl stress. The plant height, leaf area and plant biomass decreased significantly in salt-treated seedlings as compared with control. The relative water content (RWC %) of leaf decreased by 16 % at high concentrations of NaCl. There was an increase in the lipid peroxidation level and decrease in the electrolyte leakage at high concentrations of NaCl. The total free amino acid and proline contents of leaf increased by 5.5- and 43-folds, respectively in 150 mM NaCl-treated plants as compared with control. Total sugar and starch content increased significantly at high concentrations of NaCl. Chl a, Chl b, total chlorophyll and carotenoid contents decreased significantly at high salinity. Na? contents of leaf, stem and root increased in dosedependent manner. K? content remained unaffected in leaf and root and decreased in stem by salinity. The results from present study reveal that the peanut plants have an efficient adaptive mechanism to tolerate high salinity by maintaining adequate leaf water status associated with growth restriction. In order to circumvent the stress resulting from high salinity, the levels of some organic metabolites such as total free amino acids, proline, total sugars and starch were elevated. The elevated levels of the organic metabolites may possibly have some role in maintenance of
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    Physiological and Biochemical Responses Reveal the Drought Tolerance Efficacy of the Halophyte Salicornia brachiata
    (2014-02-06) Parida, Asish Kumar; Jha, Bhavanath
    The drought tolerance of Salicornia brachiata seedlings was assessed by monitoring growth, nutrient uptake, electrolyte leakage, lipid peroxidation, and biochemical responses under drought conditions simulated with 0, 10, 20, and 30 % polyethylene glycol (PEG 6000). After 7 days of drought induction, plants were harvested for measurement of various parameters. The biomass decreased and the plant height remained unchanged with PEG treatment. The total plant water content (TWC%) decreased by 11 % at the highest concentration of PEG (30 %). The electrolyte leakage and lipid peroxidation of shoots increased by 17 and 5 %, respectively, in 30 % PEG-treated plants. K? and Ca2? contents of shoots increased in a dose-dependent manner. However, in roots K? content decreased and Ca2? content remained unaffected by PEG treatment. Mg2? content increased at high concentrations of PEG (20–30 %) in shoots and decreased at the highest concentration of PEG (30 %) in roots. Total free amino acids, proline, and polyphenol contents increased progressively with increase in severity of the drought stress. Total sugar content and reducing sugar content increased in 10 and 20 % PEG-treated plants and decreased in 30 % PEG-treated plants. Our results suggest that proline and other free amino acids, sugars, and polyphenols are the main compatible solutes in S. brachiata for maintenance of osmotic balance, protection of cellular macromolecules, detoxification of the cells, and scavenging of free radicals under drought stress. A greater