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1

Comparative toxicity of insecticides on thylakoids of intact Scenedesmus bijugatus [Turp.] Kutz. and Ankistrodesmus convolutus Corda cells: measurement of chlorophyll a fluorescence

100%
Mohapatra P. K., Mohanty R. C.
Acta Hydrobiologica
|
1996
|
tom 38
|
nr 3-4
A decrease in maximum fluorescence (Fm) and fluorescence yield (Fv/Fm) and increase in non-photochemical quenching (qN) were observed in the cultures treated with quinalphos, endosulfan, and carbaryl. The effects were time dependent but most of them were observed during the first 2 h. The insecticides also effectively increased the transthylakoid pH difference (ΔpH), this being attributed to inhibition of thylakoid ATPase. Acceleration of qN showed a direct correlation with the increase in ΔpH in all cases. A. convolutus was more sensitive to all insecticides. Carbaryl was less toxic than quinalphos and endosulfan.
2

Influence of dimethoate on the structure and function of the natural phytoplankton assemblage of the Darss-Zingst bodden chain reared in a laboratory

100%
Mohapatra P. K., Schiewer U.
Polish Journal of Environmental Studies
|
1996
|
tom 05
|
nr 2
The toxic effect of the organophosphorus (OP) insecticide dimethoate on the structure and function of natural phytoplankton assemblage of brackish lake water of the Darss-Zingst bodden chain was tested in a laboratory under both short- and long-term incubation. A decrease in photosynthetic activity, an increase of photosystem II (PS II) fluorescence emission and acceleration of respiratory O2 consumption were observed as immediate responses (1 h treatment) by the sample to the OP insecticide taken at concentrations of up to 1 mg/1. Long-term exposure (8 days) of the phytoplankton assemblage to the chemical caused elimination of the sensitive species, a change in phytoplankton density and diversity, a decrease of photosynthetic activity and differential fluorescence responses of PS II. A direct relation to the number of eliminated species with insecticide concentrations and days of incubation was observed. All the tested concentrations were found to be toxic to the phytoplankton assemblage albeit acceleration of growth of certain species at 0.01 mg/1 of the insecticide. The monitoring of the fluorescence response cf PS II and respiratory O2 consumption were considered convincing parameters for short-term toxicity assessment while photosynthetic efficiency and phytoplankton diversity were found to be better indicators of long-term toxicity exposure.
3

Farm practices influence the photosynthetic performance and plant efficiency of Oryza sativa L.

81%
Chhotaray D., Chandrakala Y., Mishra C. S. K., Mohapatra P. K.
Acta Physiologiae Plantarum
|
2014
|
tom 36
|
nr 06
The photosynthetic and physiological performances of Oryza sativa L. (rice) were evaluated in organic and conventional rice–rice agroecosystems for 120 days after transplantation by measuring net photosynthesis (PN), transpiration (E), stomatal conductance (gs), intercellular CO₂ concentration (Cᵢ), chlorophyll content (SPAD) and JIP fluorescence rise. The soil health was measured as soil bacterial and fungi density and activities of soil microbial enzymes (amylase, invertase, cellulase, protease, alkaline phosphatase and dehydrogenase). The conventionally managed fields showed lower microbial density and activity than of organic fields especially after 60 days of transplantation. The crop grown in the conventional fields has significantly low level of PN and chlorophyll, but E, gs and Cᵢ did not differ significantly till 105 days after transplantation. The JIP rise was low in conventional fields than in organic fields during 90–120 days. The efficiency and plant performance parameters (ᵩP₀, ψ₀, ᵩE₀, PIᵩ, PIψ, PIABS, and PItotal) showed a rapid rate of decrease in the conventional than of organic fields. Significant positive correlation could be established between the performance and soil microbial activities, whereas the stress indicating fluorescence parameters (VJ, M₀, ᵩD₀, DI₀/RC) showed significant negative correlation with the soil parameters in both the farming systems. The result showed that JIP analysis can be used as an early indicator of soil fertility and plant performance.
4

Mercury toxicity to Chlorella vulgaris Beijerinck: protection by amino acids

81%
Mohanty L., Mohapatra D. K., Mohapatra P. K., Mohanty R. C.
Polish Journal of Environmental Studies
|
1998
|
tom 07
|
nr 1
Mercury is known to be toxic to a number of phytoplankton even at very low concentrations. The metal inhibited survival, growth and biosynthesis of chlorophyll, carbohydrate and lipid of the green alga Chlorella vulgaris at its toxic concentrations (≥ 0.1 μM), but induced the biosynthesis of proline. The addition of amino acids (Alanine, Aspargine, Glutamate, Histidine and Cysteine) to the growth medium had a significant impact on bioassay results. The toxicity was expressed differently depending on concentration and type of amino acid added to cultures. LC50s ranged from 0.68 ± 0.004 to 0.97 ± 0.008 μM and the acute toxicity of Hg2+ in amino acid supplemented media followed the order C > C + ALA > C + GLU > C + ASP > C + HIS > C + CYS. The static dose of the metal to the alga was found to be 1 + 0.006 μM but its inhibitory effect on the alga was drastically reduced with the addition of amino acids. There were positive correlations between growth and metabolic activities of the alga and concentration of amino acid added to cultures at the presence of static concentration of Hg2+. The results suggested that amino acids have moderating effects on toxicity of Hg2+ because of their ability to regulate the concentration of free Hg2+ ions in growth medium.
5

Effect of organic carbon sources on the toxicity of mercury to Chlorococcum infusionum [Schrank.] Menegh. and Ankistrodesmus falcatus [Corda] Ralfs

81%
Mohapatra P. K., Mohanty R. C., Sinha M.
Acta Hydrobiologica
|
1995
|
tom 37
|
nr 1
Abstract - Mercury at all tested concentrations was found to be less toxic to Chlorococcum infusionum than to Ankistrodesmus falcatus. Ankistrodesmus growth was inhibited at all the tested doses of the metal while Chlorococcum remained unaffected up to 0.005µM of Hg2+. A reduction of chlorophyll and protein content, decrease in Chl a/b ratio, and accumulation of glycolate was observed at inhibitory concentrations of Hg2+ whereas amino acid synthesis was not significantly affected. Both the used carbon sources caused a reduction of Hg2+ toxicity to the test algae, glucose being more effective than glutamate.
6

Effect of the pyrethroid insecticide cypermethrin on photosynthetic pigments of the cyanobacterium Anabaena doliolum Bhar.

81%
Mohapatra P. K., Patra S., Samantaray P. K., Mohanty R. C.
Polish Journal of Environmental Studies
|
2003
|
tom 12
|
nr 2
The degradation of chlorophyll a (Chl a), carotenoids and phycobiliproteins, and the fluorescence responses of the filamentous cyanobacterium Anabaena doliolum Bhar. were studied with short exposure (45 min-30 hours) to the pyrethroid insecticide cypermethrin by taking 20 μM and 50 μM of the chemical as treatment concentrations. There was significant reduction in Chl a, carotenoids and phycobiliprotein contents of cells in each of the selected concentrations of the insecticide. Pheophytin a and fluorescing and non-fluorescing chlorophyll catabolites (FCCs and NCCs) were produced as degradation products of Chl a during the exposure period. The amount of the degradation products gradually decreased with prolonged exposure of the cells to the insecticide. The pattern of degradation of carotenoids was similar to that of Chl a but the rate of degradation was less than for Chl a. The amount of lycopene also continuously decreased with increase of the insecticide concentration. There was gradual reduction of cellular phycocyanin and phycoerythrin contents of cells with rapid degradation during the first 6 hours of treatment. The fluorescence emission of phycobilisomes and photosystem II decreased with increased concentrations of insecticide and prolongation of treatment. The cyanobacterium did not show any recovery from insecticide stress during 30 hours of exposure.
7

Differences in the responses of stem diameter and pod thickness to drought stress during the grain filling stage in soybean plants

71%
Ohashi Y., Nakayama N., Saneoka H., Mohapatra P. K., Fujita K.
Acta Physiologiae Plantarum
|
2009
|
tom 31
|
nr 2
This study investigated the factor of the physiological characteristics causing the reduction of yield of soybean plants (Glycine max (L.) Merr.) by drought stress, by monitoring changes in stem diameter and pod thickness, and photosynthetic activity, partitioning of ¹³C-labeled photosynthate. Drought stress reduced the whole plant dry weight due to the decrease in leaf and pod dry matter accumulation; however, this stress did not have a significant effect on stem growth. Leaf photosynthesis was also severely decreased by drought stress in the early stage of stress treatment as leaf water potential decreased. Imposition of stress decreased pod thickness, but stem diameter increased. The adverse effect of drought stress on pod thickness was more evident at night than during the day. The stem diameter also shrank during the day and expanded at night, but the nocturnal increase in stem diameter during drought stress treatment was greater for stressed plants compared with well-watered controls. Drought stress significantly promoted ¹³C partitioning from the fed leaf to other parts of the plant; the stem was the largest beneficiary. Soluble carbohydrates accumulated in various plant parts under the influence of the stress, but starch concentration declined in all organs except the stem. These results indicated that stem growth was promoted by drought stress compared to pod growth at the early grain-filling stage.
8

In vitro plant regeneration from cotyledonary nodes of Withania somnifera (L.) Dunal and assessment of clonal fidelity using RAPD and ISSR markers

51%
Nayak S. A., Kumar S., Satapathy K., Moharana A., Behera B., Barik D. P., Achara L., Mohapatra P. K., Jena P. K., Naik S. K.
Acta Physiologiae Plantarum
|
2013
|
tom 35
|
nr 01
9

In vitro plant regeneration from cotyledonary nodes of Withania somnifera (L.) Dunal and assessment of clonal fidelity using RAPD and ISSR markers

51%
Nayak S. A., Kumar S., Satapathy K., Moharana A., Behera B., Barik D. P., Acharya L., Mohapatra P. K., Jena P. K., Naik S. K.
Acta Physiologiae Plantarum
|
2013
|
tom 35
|
nr 01
An efficient large-scale clonal propagation protocol has been described for Withania somnifera (L.) Dunal, a valuable medicinal plant, using cotyledonary nodes derived from axenic seedlings. Murashige and Skoog’s (Physiol Plant 15:473–497, 1962) (MS) medium supplemented with 1.0 mg l-1 N6-benzyladenine (BA) was found to be optimum for production of multiple shoots (100 % shoot proliferation frequency and 16.93 shoots per explant). Successive shoot cultures were established by repeatedly sub-culturing the original cotyledonary node on a fresh medium after each harvest of newly formed shoots. Multiple shoot proliferation was also achieved from nodal segments derived from in vitro raised shoots on MS medium augmented with 1.0 mg l-1 BA. Regenerated shoots were best rooted (95.2 %, 38.7 roots per shoot) in half-strength MS medium supplemented with 1.0 mg l-1 indole-3-butyric acid. The plantlets were successfully acclimated and established in soil. Random amplified polymorphic DNA and inter-simple sequence repeats analysis revealed a homogeneous amplification profile for all micropropagated plants analyzed validating the genetic fidelity of the in vitro regenerated plants.
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