Browsing by Author "Rajneesh Kumar Srivastava"

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Cadmium Alters Mitochondrial Membrane Potential, Inhibits Electron Transport Chain Activity and Induces Callose Deposition in Rice Seedlings
(Springer New York LLC, 2018) Rajneesh Kumar Srivastava; Ritika Rajpoot; Poonam Pandey; Anjana Rani; R.S. Dubey
In the present study, seedlings of indica rice (Oryza sativa L.) cultivars were subjected to 100 and 200 µM Cd(NO3)2 treatment in hydroponics for 10 days which resulted in a marked decline in the growth of the seedlings compared to untreated controls. The integrity of the root cell plasma membrane was significantly decreased and high callose deposition in roots was observed. We observed that mitochondrial functioning was adversely affected in Cd-treated seedling marked by alteration of mitochondrial membrane potential and inhibition of electron transport chain activity. In particular, the activity of the electron transport chain Complex II was more inhibited with Cd treatment compared to the activities of Complex I and Complex IV. Transmission electron microscopic (TEM) analysis of rice leaves from control and Cd-treated seedlings showed significant alteration in membrane composition. Cd treatment at 100 and 200 µM resulted in partial to full disintegration of the mitochondrial membrane, respectively. The increased callose deposition might be a defense response against Cd toxicity. The findings indicate that Cd exposure to rice seedlings causes damage to mitochondria and inhibition of mitochondrial electron transport activity which would ultimately contribute to inhibited growth of rice plants in Cd-polluted soils. © 2017, Springer Science+Business Media, LLC.
Cadmium and lead interactive effects on oxidative stress and antioxidative responses in rice seedlings
(Springer-Verlag Wien, 2014) Rajneesh Kumar Srivastava; Poonam Pandey; Ritika Rajpoot; Anjana Rani; R.S. Dubey
Interactive effects of two heavy metal pollutants Cd and Pb in the growth medium were examined on their uptake, production of reactive oxygen species (ROS), induction of oxidative stress and antioxidative defence responses in Indica rice (Oryza sativa L.) seedlings. When rice seedlings in sand culture were exposed to 150 μM Cd (NO3)2 or 600 μM Pb (CH3COO)2 individually or in combination for 8-16 days, a significant reduction in root/shoot length, fresh weight, relative water content, photosynthetic pigments and increased production of ROS (O2̇- and H2O2) was observed. Both Cd and Pb were readily taken up by rice roots and localisation of absorbed metals was greater in roots than in shoots. When present together in the growth medium, uptake of both the metals Cd and Pb declined by 25-40 %. Scanning electron microscope (SEM) imaging of leaf stomata revealed that Pb caused more distortion in the shape of guard cells than Cd. Dithizone staining of roots showed localisation of absorbed Cd on root hairs and epidermal cells. Both Cd and Pb caused increased lipid peroxidation, protein carbonylation, decline in protein thiol and increase in non-protein thiol. The level of reduced forms of non-enzymic antioxidants glutathione (GSH) and ascorbate (AsA) and their redox ratios (GSH/AsA) declined, whereas the activities of antioxidative enzymes superoxide dismutase (SOD) and guaiacol peroxidase (GPX) increased in metal treated seedlings compared to controls. In-gel activity staining also revealed increased intensities of SOD and GPX isoforms with metal treatments. Catalase (CAT) activity increased during early days (8 days) of metal exposure and declined by 16 days. Results suggest that oxidative stress is an important component in expression of Cd and Pb toxicities in rice, though uptake of both metals gets reduced considerably when present together in the medium. © 2014 Springer-Verlag Wien.
Exogenous application of calcium and silica alleviates cadmium toxicity by suppressing oxidative damage in rice seedlings
(Springer-Verlag Wien, 2015) Rajneesh Kumar Srivastava; Poonam Pandey; Ritika Rajpoot; Anjana Rani; Arti Gautam; R.S. Dubey
The present study was undertaken to examine the possible roles of calcium (Ca2+) and silica (Si) in protection against oxidative damage due to Cd2+ toxicity in rice (Oryza sativa L.) seedlings grown in hydroponics. Rice seedlings raised for 12 days in hydroponics containing Cd(NO3)2 (75 μM) showed reduced growth; increase in the level of reactive oxygen species (ROS) (O2 •− and H2O2), thiobarbituric acid reactive substances (TBARSs) and protein carbonylation; and increase in the activity of antioxidant enzymes—superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (GPX) compared to untreated controls. Exogenously added Ca2+ (2 mM) and Si (200 μM) significantly alleviated negative effect of Cd2+ by restoration of growth of the seedlings, suppression of Cd2+ uptake and restoration of root plasma membrane integrity. The levels of O2 •−, H2O2, lipid peroxidation and protein carbonyls were much lower when Ca2+ and Si were added in the growth medium along with Cd2+ as compared to Cd-alone-treated seedlings. Ca2+ and Si lowered Cd-induced increase in SOD, GPX and APX activities while they elevated Cd-induced decline in CAT activity. Using histochemical staining of O2 •− and H2O2 in leaf tissues, it was further confirmed that added Ca2+ and Si suppressed Cd-induced accumulation of O2 •− and H2O2 in the leaves. The results suggest that exogenous application of Ca2+ and Si appears to be advantageous for rice plants in alleviating Cd2+ toxicity effects by reducing Cd2+ uptake, decreasing ROS production and suppressing oxidative damage. The observations indicate that Ca2+ and Si treatments can help in reducing Cd2+ toxicity in rice plants. © Springer-Verlag Wien 2014.
Manganese-induced oxidative stress, ultrastructural changes, and proteomics studies in rice plants
(Springer, 2021) Ritika Rajpoot; Rajneesh Kumar Srivastava; Anjana Rani; Poonam Pandey; R.S. Dubey
Manganese (Mn) is an essential element for plant growth but it becomes phytotoxic at higher concentrations. The effect of Mn-excess in hydroponics medium was examined on growth, oxidative stress, and ultrastructural changes in chloroplasts and mitochondria as well proteomic alterations in rice (Oryza sativa L.) seedlings. Seedlings grown with 1 mM and 2 mM Mn in nutrient medium for 8 days showed decline in length and fresh biomass, and decline in net photosynthetic rate, transpiration rate, and stomatal conductance. Shoots of the seedlings had higher Mn content than roots. Mn-treated seedlings showed increased production of O2·−, H2O2, and .OH, increased lipid peroxidation, increased carbonylation of proteins, and increased proteolytic activity compared to untreated seedlings. Mn-treated seedlings showed disorganization and swelling of chloroplasts with appearance of plastoglobuli in TEM images and deformity in shape of mitochondria. Using confocal microscopy depolarization of mitochondrial membrane was observed marked by green fluorescence of JC-1 dye monomers in Mn-treated roots. Proteomics studies from leaves of Mn-treated seedlings involving 2DE and PDQuest analysis showed differential expression of 23 proteins, among which MALDI-TOF/TOF mass spectrometry analysis revealed Mn-led downregulation of photosynthesis-related proteins, namely oxygen-evolving complex protein associated with PSII, PAP-3, enzyme involved in protein folding peptidyl-prolyl cis-trans isomerase (PPIase) and carbohydrate metabolizing enzymes hydrolase, fructose-bisphosphate aldolase, transketolase, and isocitrate dehydrogenase, whereas ATP-dependent Clp protease, peroxidase, and nucleic acid–binding proteins were downregulated due to Mn treatment. Results indicate that Mn-excess inhibits growth of rice plants with induction of oxidative stress, causing structural alterations in chloroplasts, mitochondria, inhibiting photosynthesis, and downregulating many photosynthesis and carbohydrate metabolism–related proteins. © 2020, Springer-Verlag GmbH Austria, part of Springer Nature.
Physiological Mechanisms of Nitrogen Absorption and Assimilation in Plants under Stressful Conditions
(Taylor and Francis, 2014) Rama Shanker Dubey; Rajneesh Kumar Srivastava; Mohammad Pessarakli
Nitrogen is the most important element for plant growth and development. In the cell, it is present as constituent of proteins, amino acids, nucleic acids, coenzymes, vitamins, chlorophylls, hormones, and functional groups of enzymes. It is a major part of chlorophyll and the green color of plants. It is a key constituent of nucleic acids that serve as genetic material and regulate vital processes like growth, reproduction, and heredity. Being a principal macronutrient, N has a special place in plant nutrition, and plants require it in large amounts. Though N is the most abundant element in our atmosphere, majority of the plants cannot utilize it directly in the elemental form. An adequate supply of N in the soil is essential to maintain proper growth and yield of crops. The availability of N in the soil is due to N2 xation by symbiotic and nonsymbiotic bacteria; mineralization of organic matter, manure, and animal waste products; or application of inorganic N fertilizers. Though the natural sources can make significant contributions to soil N levels, with the advent of modern agricultural practices, to meet the needs of high-yielding varieties of crops, inorganic N fertilizers have become major input to the soil in order to achieve required optimum yields. To meet the increasing food demand for the growing population, keeping pace with high N requirements of the improved varieties of crops, in the near future, excessive uses of different forms of N fertilizers are anticipated. © 2014 by Taylor & Francis Group, LLC.
Protective Role of Mentha arvensis Aqueous Extract against Manganese Induced Toxicity by Reducing Mn Translocation and Promoting Antioxidative Defense in growing Indica Rice Seedlings
(Korean Society of Crop Science, 2018) Ritika Rajpoot; Anjana Rani; Rajneesh Kumar Srivastava; Poonam Pandey; R.S. Dubey
Mentha arvensis L. (Ma) leaf extract, a wide source of natural antioxidants is widely used to protect animal cells against oxidative stress. In the current study, we have studied the ameliorative effects of Ma leaf extract on Mn induced oxidative stress in rice (Oryza sativa L.) seedlings. Hydroponically grown rice seedlings treated with 1.5 mM MnCl2 showed a decline in vigour and contents of photosynthetic pigments, increased production of reactive oxygen species (O2˙‾, H2O2, and.OH), lipid peroxidation, protein thiol and carbonyl contents along with increased activity of antioxidative enzymes- superoxide dismutase (SOD), guaiacol peroxidase (GPX) and ascorbate peroxidase (APX). The activity of catalase (CAT), however, declined in the seedlings after prolonged Mn treatment of 8 days. Interestingly exogenous application of Ma leaf extract (638.4 mg ml-1) effectively restored the Mn-induced decline in seedling vigour, photosynthetic pigments, increased levels of H2O2, lipid peroxides and altered activities of antioxidative enzymes. The results indicate that exogenous application of Ma leaf extract significantly lowers the toxic effects of Mn in rice seedlings by modulating Mn translocation and reducing oxidative stress. © 2018, Korean Society of Crop Science (KSCS) and Springer Nature B.V.
Salicylic acid alleviates aluminum toxicity in rice seedlings better than magnesium and calcium by reducing aluminum uptake, suppressing oxidative damage and increasing antioxidative defense
(2013) Poonam Pandey; Rajneesh Kumar Srivastava; R.S. Dubey
Aluminum toxicity is a major constraint to crop production in acid soils. The present study was undertaken to examine the comparative ameliorating effects of salicylic acid, Ca and Mg on Al toxicity in rice (Oryza sativa L.) seedlings grown in hydroponics. Al treatment (0.5 mM AlCl3) caused decrease in plant vigour, loss of root plasma membrane integrity, increased contents of O2•-, H2O2, lipid peroxidation, protein carbonyls and decline in the level of protein thiol. Al treatment caused significant changes in activity of antioxidative enzymes in rice seedlings. Exogenously added salicylic acid (60 μM), Ca (1 mM) and Mg (0.25 mM) significantly alleviated Al toxicity effects in the seedlings marked by restoration of growth, suppression ofAl uptake, restoration of root plasma membrane integrity and decline in O2•-, H 2O2, lipid peroxidation and protein carbonyl contents. Salicylic acid, Ca and Mg suppressed Al-induced increase in SOD, GPX and APX activities while it elevated Al-induced decline in CAT activity. By histochemical staining of O2•- using NBT and H 2O2 using DAB, it was further confirmed that added salicylic acid, Ca orMg decreasedAl-induced accumulation ofO2 •- and H2O2 in the leaf tissues. Results indicate that exogenously added salicylic acid, Ca or Mg alleviates Al toxicity in rice seedlings by suppressing Al uptake, restoring root membrane integrity, reducing ROS level and ROS induced oxidative damage and regulating the level of antioxidative enzyme activities. Further salicylic appears to be superior toMg and Ca in alleviating Al toxicity effects in rice plants. © Springer Science+Business Media New York 2013.
Terminalia arjuna bark extract alleviates nickel toxicity by suppressing its uptake and modulating antioxidative defence in rice seedlings
(Springer-Verlag Wien, 2016) Ritika Rajpoot; Anjana Rani; Rajneesh Kumar Srivastava; Poonam Pandey; R.S. Dubey
Terminalia arjuna (Ta) bark contains various natural antioxidants and has been used to protect animal cells against oxidative stress. In the present study, we have examined alleviating effects of Ta bark aqueous extract against Ni toxicity in rice (Oryza sativa L.). When rice seedlings were raised for 8 days in hydroponics in Yoshida nutrient medium containing 200 μM NiSO4, a decline in height, reduced biomass, increased Ni uptake, loss of root plasma membrane integrity, increase in the level of O2˙−, H2O2 and ˙OH, increased lipid peroxidation, decline in photosynthetic pigments, increase in the level of antioxidative enzymes superoxide dismutase, catalase and glutathione peroxidase and alterations in their isoenzyme profile patterns were observed. Transmission electron microscopy (TEM) showed damage to chloroplasts marked by disorganised enlarged starch granules and disrupted thylakoids under Ni toxicity. Exogenously adding Ta bark extract (3.2 mg ml−1) to the growth medium considerably alleviated Ni toxicity in the seedlings by reducing Ni uptake, suppressing generation of reactive oxygen species, reducing lipid peroxidation, restoring level of photosynthesis pigments and ultrastructure of chloroplasts, and restoring levels of antioxidative enzymes. Results suggest that Ta bark extract considerably alleviates Ni toxicity in rice seedlings by preventing Ni uptake and reducing oxidative stress in the seedlings. © 2015, Springer-Verlag Wien.
Water deficit and aluminum interactive effects on generation of reactive oxygen species and responses of antioxidative enzymes in the seedlings of two rice cultivars differing in stress tolerance
(Springer Verlag, 2016) Poonam Pandey; Rajneesh Kumar Srivastava; Ritika Rajpoot; Anjana Rani; Akhilesh Kumar Pandey; R.S. Dubey
Aluminum (Al) is a major constraint to crop productivity in acid soils, whereas water deficit severely limits crop production in arid and semi-arid regions of the world. The objective of the present study was to examine the effects of both stresses, Al excess and water deficit, individually and in combination on the production of the reactive oxygen species (ROS) superoxide anion (O2˙−), hydrogen peroxide (H2O2), hydroxyl radical, and lipid peroxidation and the activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and guaiacol peroxidase (GPX) in the seedlings of two rice (Oryza sativa L.) cvs. Malviya-36 (sensitive to water deficit and Al) and Vandana (tolerant to water deficit and Al). When 15-day grown seedlings were exposed to water deficit (created with 15 % polyethylene glycol, PEG-6000) or Al (1 mM AlCl3) treatment or both treatments together for 24–72 h, the lengths and fresh weights of root/shoot declined in the seedlings of the sensitive cultivar, whereas in the tolerant seedlings, either little or insignificant decline in these parameters was observed due to the treatments. Biochemical determinations and histochemical studies revealed that under a similar level of water deficit, Al, or combined treatment, seedlings of sensitive cultivar showed a higher level of production of O2˙−, H2O2, hydroxyl radical, and lipid peroxides compared to the tolerant seedlings. Seedlings of tolerant cultivars, both in roots and shoots, had constitutively higher activity levels of antioxidative enzymes SOD, CAT, and GPX and showed a greater increase in activity under water deficit or Al treatment alone or in combination compared to the similarly treated seedlings of sensitive cultivar. Our results suggest that a lower constitutive level of ROS and a high antioxidative enzyme capacity are associated with tolerance to both water deficit and Al excess in rice seedlings. © 2015, Springer-Verlag Berlin Heidelberg.
Water deficit and aluminum tolerance are associated with a high antioxidative enzyme capacity in Indica rice seedlings
(2014) Poonam Pandey; Rajneesh Kumar Srivastava; R.S. Dubey
Plant growth and productivity are greatly affected due to changes in the environmental conditions. In the present investigation, the interactive effects of two important abiotic stresses, i.e., water deficit and Al toxicity, were examined in the seedlings of two rice (Oryza sativa L.) cvs. Malviya-36 (water deficit/Al sensitive) and Vandana (water deficit/Al tolerant). When 15 days grown seedlings were exposed to water deficit (created with 15 % polyethylene glycol 6000) or Al (1 mM AlCl3) treatment or both the treatments together for 48 h, the lengths of root/shoot, relative water content, and chlorophyll greatly declined in the seedlings of the sensitive cultivar, whereas in the tolerant seedlings, either little or insignificant decline in these parameters was observed due to the treatments. Seedlings subjected to water deficit or Al treatment alone or in combination showed increased intensity of the isoenzyme activity bands of superoxide dismutase (SOD), guaiacol peroxidase (GPX), and ascorbate peroxidase (APX) in in-gel activity staining studies. Water deficit caused decrease in intensity of catalase (CAT) activity bands; however, when seedlings were exposed to AlCl3 alone or in combination with water deficit, the intensity of the CAT isoforms increased in both the rice cultivars. The level of expression of the activity bands of SOD, CAT, GPX, and APX was always higher in the seedlings of tolerant cv. Vandana compared to the sensitive cv. Malviya-36 under both controls as well as stress treatments. Higher intensity of isozymes representing higher activity levels of antioxidative enzymes in the rice seedlings and their further increase under water deficit, Al exposure, or in combination of both the stresses appears to serve as useful marker for specifying a combination of water deficit and Al tolerance in rice. © 2013 Springer-Verlag Wien.