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Kumar D.,Allahabad University | Singh V.P.,Government Ramanuj Pratap Singhdev Post Graduate College | Tripathi D.K.,Allahabad University | Tripathi D.K.,Banaras Hindu University | And 2 more authors.
International Journal of Phytoremediation | Year: 2015

Hydroponic experiments were conducted to investigate the effect of arsenic on seedlings of Wrightia arborea and Holoptelea integrifolia. Results revealed that W. arborea could tolerate much higher arsenic concentration than H. integrifolia. Therefore, further investigations were focused on W. arborea using higher arsenic concentrations (0.2–2.0 mM). Seedlings of W. arborea accumulated about 312–2147 and 1048–5688 mg/kg dry weight of arsenic in shoots and roots, respectively, following treatments with 0.2–1.5 mM of arsenic without exhibiting arsenic toxicity signs. However, arsenic at 2.0 mM caused decline in growth. Macronutrients content such as Ca, S (except at 2.0 mM), and K (only in root) increased while Mg, P, and K (shoot) decreased by arsenic treatments. However, the content of micronutrients was enhanced under arsenic treatments. Non-protein thiols (NP-SH) showed positive correlations with arsenic doses up to 0.2–1.5 mM but at 2.0 mM there was a decline in NP-SH thus suggesting important role of NP-SH in imparting arsenic tolerance. This study demonstrated that W. arborea that could tolerate arsenic concentrations up to 0.2–1.5 mM may be useful in arsenic phytoremediation programs. © 2015, Taylor & Francis Group, LLC.

Singh R.,Allahabad University | Singh S.,Allahabad University | Parihar P.,Allahabad University | Singh V.P.,Government Ramanuj Pratap Singhdev Post Graduate College | Prasad S.M.,Allahabad University
Journal of Plant Physiology | Year: 2015

Retrograde signaling, defined as the signaling events leading from the plastids to the nucleus, coordinates the expression of plastid and nuclear genes and is crucial for metabolic as well as developmental processes of the plastids. In the recent past, the identification of various components that are involved in the generation and transmission of plastid-originated retrograde signals and the regulation of nuclear gene expression has only provided a glimpse of the plastid retrograde signaling network, which remains poorly understood. The basic assumptions underlying our current understanding of retrograde signaling stayed untouched for many years. Therefore, an attempt has been made in this review article to summarize established facts and recent advances regarding various retrograde signaling pathways derived from different sources, the identification of key elements mediating retrograde signal transduction and also to give an overview of possible signaling molecules that remain to be investigated. © 2015 Elsevier GmbH.

Singh R.,Allahabad University | Singh S.,University of Lucknow | Parihar P.,Allahabad University | Singh V.P.,Government Ramanuj Pratap Singhdev Post Graduate College | Prasad S.M.,Allahabad University
Ecotoxicology and Environmental Safety | Year: 2015

The exposure to low or high concentrations of arsenic (As), either due to the direct consumption of As contaminated drinking water, or indirectly through daily intake of As contaminated food may be fatal to the human health. Arsenic contamination in drinking water threatens more than 150 millions peoples all over the world. Around 110 millions of those peoples live in 10 countries in South and South-East Asia: Bangladesh, Cambodia, China, India, Laos, Myanmar, Nepal, Pakistan, Taiwan and Vietnam. Therefore, treatment of As contaminated water and soil could be the only effective option to minimize the health hazard. Therefore, keeping in view the above facts, an attempt has been made in this paper to review As contamination, its effect on human health and various conventional and advance technologies which are being used for the removal of As from soil and water. © 2014 Elsevier Inc.

Parihar P.,Allahabad University | Singh S.,University of Lucknow | Singh R.,Allahabad University | Singh V.P.,Government Ramanuj Pratap Singhdev Post Graduate College | Prasad S.M.,Allahabad University
Environmental Science and Pollution Research | Year: 2015

The environmental stress is a major area of scientific concern because it constraints plant as well as crop productivity. This situation has been further worsened by anthropogenic activities. Therefore, there is a much scientific saddle on researchers to enhance crop productivity under environmental stress in order to cope with the increasing food demands. The abiotic stresses such as salinity, drought, cold, and heat negatively influence the survival, biomass production and yield of staple food crops. According to an estimate of FAO, over 6 % of the world’s land is affected by salinity. Thus, salinity stress appears to be a major constraint to plant and crop productivity. Here, we review our understanding of salinity impact on various aspects of plant metabolism and its tolerance strategies in plants. © 2014, Springer-Verlag Berlin Heidelberg.

Singh M.,Allahabad University | Pratap Singh V.,Government Ramanuj Pratap Singhdev Post Graduate College | Dubey G.,University of Rajasthan | Mohan Prasad S.,Allahabad University
Ecotoxicology and Environmental Safety | Year: 2015

Hydroponic experiments were conducted to investigate an effect of exogenous application of proline (Pro; 25μM) in alleviating arsenate (AsV; 5 and 25μM) toxicity in Solanum melongena L. (eggplant) seedlings. Exposure of AsV declined growth of eggplant, which was coincided with an enhanced accumulation of As. However, exogenous Pro application alleviated AsV toxicity in eggplant seedlings by reducing the accumulation of As. The fluorescence characteristics (JIP-test): ϕP0, Ψ0, ϕE0, PIABS, ABS/RC, TR0/RC, ET0/RC, DI0/RC, NPQ and qP were also affected by AsV. However, the effects of AsV were more prominent on PIABS DI0/RC and NPQ. In Pro treated seedlings, following parameters viz. ϕP0, Ψ0, ϕE0 and PIABS were stimulated, while, energy flux parameters (ABS/RC, TR0/RC, ET0/RC and DI0/RC) were inhibited. Toxic effects of AsV on photochemistry of photosystem II (PS II) were ameliorated by an exogenous application of Pro. Oxidative stress markers: superoxide radical, hydrogen peroxide and malondialdehyde (lipid peroxidation) were enhanced by AsV exposure, however, their levels were significantly diminished by an exogenous application of Pro. Treatment of AsV stimulated the activities of superoxide dismutase, peroxidase and catalase except that of glutathione-S-transferase. Exogenous Pro application improved the activities of enzymatic antioxidants. The level of endogenous Pro was higher in AsV treated as well as in Pro fed seedlings. The activity of a key enzyme of Pro biosynthesis: δ1-pyrroline-5-carboxylate synthetase was higher in Pro fed seedlings. The activity of Pro dehydrogenase was inhibited under AsV stress, and its activity was minimum in case of Pro+AsV combination. These results indicate that Pro metabolism could play a key role in regulating the accumulation of As and levels of antioxidants, which concomitantly result into a better growth of eggplant seedlings when compared to the AsV treatments alone. © 2015 Elsevier Inc.

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