Modulation of salt stress in paddy field cyanobacteria with exogenous application of gibberellic acid: growth behavior and antioxidative status.

Unlabelled: The present study explores the possible function of gibberellic acid (GA: 20 µM) in reducing salt (NaCl) induced toxicity in two diazo-trophic cyanobacteria i.e. and .

Differential response of copper nanoparticles and ionic copper on growth, chlorophyll fluorescence, oxidative stress, and antioxidant machinery of two paddy field cyanobacteria.

The current study explored the role of ionic copper (CuCl; 0.2 µM and 1 µM) and synthesized copper nanoparticles (CuNPs; 0.2 mM and 1 mM) in the two paddy field cyanobacteria (Nostoc muscorum ATCC 27893 and Anabaena sp.

Arsenate and arsenite-induced inhibition and recovery in two diazotrophic cyanobacteria Nostoc muscorum and Anabaena sp.: study on time-dependent toxicity regulation.

Exposure time, metal bio-accumulation, and upregulation of ascorbate-glutathione (AsA-GSH) cycle are the key factor that provide tolerance against heavy metal stress. Thus, the current study is an endeavor to prove our hypothesis that regulation of arsenate (As: 50, 100, and 150 mM) and arsenite (As: 50, 100, and 150 μM) toxicity is time dependent (48-96 h) due to modulation in bio-accumulation pattern, AsA-GSH cycle, and non-enzymatic antioxidants in two paddy field cyanobacteria Nostoc muscorum ATCC27893 and Anabaena sp. PCC7120.

Effect of Time Interval on Arsenic Toxicity to Paddy Field Cyanobacteria as Evident by Nitrogen Metabolism, Biochemical Constituent, and Exopolysaccharide Content.

Arsenic poisoning in aquatic ecosystem is a global concern that obstructs the productivity of agricultural lands (paddy fields) by targeting the growth of cyanobacteria. The cyanobacteria also tolerate and accumulate elevated concentration of arsenic (As) inside the cell and excrete out from cells in less toxic forms after the successive time interval. Thus to validate this, the study was carried out at two different time intervals, i.

Phytohormone up-regulates the biochemical constituent, exopolysaccharide and nitrogen metabolism in paddy-field cyanobacteria exposed to chromium stress.

Background: Cyanobacteria are well known for their inherent ability to serve as atmospheric nitrogen fixers and as bio-fertilizers; however, increased contaminants in aquatic ecosystem significantly decline the growth and function of these microbes in paddy fields. Plant growth regulators play beneficial role in combating the negative effects induced by heavy metals in photoautotroph. Current study evaluates the potential role of indole acetic acid (IAA; 290 nm) and kinetin (KN; 10 nm) on growth, nitrogen metabolism and biochemical constituents of two paddy field cyanobacteria Nostoc muscorum ATCC 27893 and Anabaena sp.

Kinetin alleviates chromium toxicity on growth and PS II photochemistry in Nostoc muscorum by regulating antioxidant system.

The present study was undertaken to evaluate the metal toxicity alleviating effects of kinetin (KN, 10 nM) on growth, photosynthetic pigments and photochemistry of PS II in the cyanobacterium Nostoc muscorum exposed to chromium (Cr) stress (100 and 150 µM). Chromium declined growth, photosynthetic pigments (chlorophyll a, phycocyanin and carotenoids), photosynthetic oxygen evolution rate and parameters of fluorescence kinetics (ϕP, F/F, ϕE, Ψ and PI except F/F) in concentration dependent manner, while stimulating effects on respiration, energy flux parameters (ABS/RC, TR/RC, ET/RC and DI/RC), oxidative stress biomarkers i.e.

Toxicity assessment of arsenate and arsenite on growth, chlorophyll a fluorescence and antioxidant machinery in Nostoc muscorum.

The present study deals with impact of varied doses of arsenite (As; 50, 100 and 150 µM) and arsenate (As; 50, 100 and 150 mM) on growth, photosynthetic pigments, photochemistry of photosystem II, oxidative biomarkers, (O¯, HO and MDA equivalents contents) and activity of antioxidant enzymes in diazotrophic cyanobacterium Nostoc muscorum after 48 and 96 h of the treatments. The reduction in growth, pigment contents (Chl a, Phy and Car) and PS II photochemistry was found to increase with enhanced accumulation of test metal in cells, and the damaging effect on photosynthetic pigments showed the order (Phy > chl a> Car). The negative effect on PS II photochemistry was due to significant decrease in the value of JIP kinetics ϕP, F/F, ϕE,Ψ and PI except F/F and significant rise in values of energy flux parameters such as ABS/RC, TR/RC, ET/RC and DI/RC.

Pretilachlor toxicity is decided by discrete photo-acclimatizing conditions: Physiological and biochemical evidence from Anabaena sp. and Nostoc muscorum.

The current study was undertaken to elucidate the impact of the herbicide pretilachlor (3 µg ml and 6 µg ml) on cyanobacteria, Nostoc muscorum ATCC 27893 and Anabaena sp. PCC 7120 under three levels of photoacclimatization (suboptimum, 25 µmol photon m s; optimum, 75 µmol photon m s; and supra-optimum, 225 µmol photon m s) by analyzing certain physiological (biomass accumulation, photosynthesis, Chl a fluorescence and respiration) and biochemical parameters (photosynthetic pigments‒ chlorophyll a, carotenoids and phycocyanin; reactive oxygen species‒ O¯, HO, lipid peroxidation; antioxidant system‒ superoxide dismutase, peroxidise, catalase and glutathione-S-transferase). The light conditioning played the most prominent role in deciding the extent of herbicide toxicity on both the tested cyanobacteria as the maximum toxicity was observed in suboptimum light acclimatized cyanobacterial cells corroborated by the least growth in the same cells.

Oxygen toxicity and antioxidative responses in arsenic stressed Helianthus annuus L. seedlings against UV-B.

In order to know the impact of elevated level of UV-B on arsenic stressed Helianthus annuus L. var. DRSF-113 plants, certain physiological (growth - root and shoot lengths, their fresh masses and leaf area; photosynthetic competence and respiration) and biochemical parameters (pigments - Chl a and b, Car, anthocyanin and flavonoids; reactive oxygen species - superoxide radicals, HO; reactive carbonyl group, electrolyte leakage; antioxidants - superoxide dismutase, peroxidise, catalase, glutathione-S-transferase, proline) of their seedlings were analysed under the simultaneous exposures of two arsenic doses (6mgkg soil, As; and 12mgkg soil, As) and two UV-B doses (1.