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Singh S.,Allahabad University | Srivastava P.K.,Allahabad University | Srivastava P.K.,Pt Ravi Shankar Tripathi Government Degree College | Kumar D.,Allahabad University | And 4 more authors.
Biocatalysis and Agricultural Biotechnology | Year: 2015

This study was aimed to investigate an impact of different concentrations of lead (Pb: 50-300μM) and chromium (Cr: 50-300μM) on maize seedlings (Zea mays L.). Results revealed that Pb and Cr at their 300μM concentrations showed significant (P<0.05) reduction in growth, photosynthetic pigments, protein and mineral contents (except S), which were accompanied by a significant increase in the accumulation of Pb and Cr, lipid peroxidation (measured as malondialdehyde; MDA) and hydrogen peroxide (H2O2). Mineral distribution and anatomical traits were also severely affected at 300μM of Pb and Cr concentration. Moreover, in comparison to Pb, different Cr treatments up to 200μM showed severe toxicity responses and significantly hampered the growth, photosynthetic pigments, minerals (except S) and anatomical features of the maize seedlings due to an increase in the accumulation of Cr in tissues and oxidative stress.Shoot and root anatomy of maize seedlings was severely affected up to 200. μM concentration of Cr while Pb showed trivial impact on anatomical features. Interestingly, the thickness of leaf midrib increased which could be correlated with the increased level of Pb and Cr in the cell wall, representing an approach to avoid their translocation to photosynthetic tissues. Epiblema and endodermis of the root were thickened while cortical cells were degraded. An increase in the number of protoxylem, perhaps had increased the availability of water in roots under different concentrations of Pb and Cr which could have protected the plants under the stress conditions. © 2015 Elsevier Ltd. Source

Singh V.P.,Allahabad University | Singh V.P.,Government Ramanuj Pratap Singhdev Post Graduate College | Srivastava P.K.,Allahabad University | Srivastava P.K.,Pt Ravi Shankar Tripathi Government Degree College | Prasad S.M.,Allahabad University
Plant Physiology and Biochemistry | Year: 2013

Hydroponic experiments were conducted to investigate whether exogenous addition of nitric oxide (NO) as sodium nitroprusside (SNP) alleviates arsenic (As) toxicity in Luffa acutangula (L.) Roxb. seedlings. Arsenic (5 and 50μM) declined growth of Luffa seedlings which was accompanied by significant accumulation of As. SNP (100μM) protected Luffa seedlings against As toxicity as it declined As accumulation significantly. The photosynthetic pigments and chlorophyll fluorescence parameters such as Fv/Fm, Fv/F0, Fm/F0 and qP were decreased while NPQ was raised by As. However, the toxic effects of As on photosynthesis were significantly ameliorated by SNP. The oxidative stress markers such as superoxide radical, hydrogen peroxide and malondialdehyde (lipid peroxidation) contents were enhanced by As, however, these oxidative indices were diminished significantly in the presence of SNP. As treatment stimulated the activities of SOD and CAT while the activities of APX and GST, and AsA content and AsA/DHA ratio were decreased. Upon SNP addition, along with further rise in SOD and CAT activity, APX and GST activity, and levels of AsA and AsA/DHA ratio were restored considerably. Overall results revealed that significant accumulation of As suppressed growth, photosynthesis, APX and GST activities and decreased AsA content, hence led to the oxidative stress. However, the addition of SNP protected seedlings against As stress by regulating As accumulation, oxidative stress and antioxidant defense system. © 2013 Elsevier Masson SAS. Source

Srivastava P.K.,Allahabad University | Srivastava P.K.,Pt Ravi Shankar Tripathi Government Degree College | Singh V.P.,Allahabad University | Singh V.P.,Government Ramanuj Pratap Singhdev Post Graduate College | Prasad S.M.,Allahabad University
Ecotoxicology and Environmental Safety | Year: 2014

The present study assessed the comparative responses on the specific growth rate, nitrogen metabolism and enzymes associated with nitrogen metabolism in two nitrogen fixing cyanobacteria-Nostoc muscorum and Phormidium foveolarum exposed to two UV-B doses (low; UV-BL: 0.5472kJm-2 and high; UV-BH: 5.472kJm-2) and two doses of the insecticide chlorpyrifos (O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate; low i.e. CPL, 1μgml-1 and high i.e. CPH, 2μgml-1) singly and in combination. The specific growth rate, NO3 - and NO2 - uptake, nitrate assimilating enzymes - nitrate reductase and nitrite reductase and ammonium assimilating enzymes - glutamine synthetase and glutamate synthase were severely affected when treated either with CPH or/and UV-BH while glutamate dehydrogenase exhibited a stimulatory response. CPL also reduced all the measured parameters (except GDH activity) after 24h, however, a stimulatory effect was observed after 72h due to an increase in nitrogen metabolism (and other antioxidant) enzymes during this period. UV-BL did not cause significant alteration in the studied parameters while in combination with CP doses, it either alleviated the inhibitory effects or further enhanced the CPL induced activities of these enzymes (except GDH). Overall results indicate the resistant nature of P. foveolarum against the inhibitory doses of UV-B and chlorpyrifos in comparison to N. muscorum. © 2014 Elsevier Inc. Source

Yadav G.,Allahabad University | Srivastava P.K.,Allahabad University | Srivastava P.K.,Pt Ravi Shankar Tripathi Government Degree College | Singh V.P.,Allahabad University | And 2 more authors.
Biological Trace Element Research | Year: 2014

The present study is aimed at assessing the extent of arsenic (As) toxicity under three different light intensities - optimum (400 μmole photon m -2 s-1), sub-optimum (225 μmole photon m-2 s-1), and low (75 μmole photon m-2 s-1) - exposed to Helianthus annuus L. var. DRSF-113 seedlings by examining various physiological and biochemical parameters. Irrespective of the light intensities under which H. annuus L. seedlings were grown, there was an As dose (low, i.e., 6 mg kg-1 soil, As1; and high, i.e., 12 mg kg-1 soil, As2)-dependent decrease in all the growth parameters, viz., fresh mass, shoot length, and root length. Optimum light-grown seedlings exhibited better growth performance than the sub-optimum and low light-grown seedlings; however, low light-grown plants had maximum root and shoot lengths. Accumulation of As in the plant tissues depended upon its concentration used, proximity of the plant tissue, and intensity of the light. Greater intensity of light allowed greater assimilation of photosynthates accompanied by more uptake of nutrients along with As from the medium. The levels of chlorophyll a, b, and carotenoids declined with increasing concentrations of As. Seedlings acquired maximum Chl a and b under optimum light which were more compatible to face As1 and As2 doses of As, also evident from the overall status of enzymatic (SOD, POD, CAT, and GST) and non-enzymatic antioxidant (Pro). © 2014 Springer Science+Business Media. Source

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