A rapid electron microscopic diagnosis of potato leafroll virus     

S. Sarkar 《Potato Research》1975,18(2):227-236

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Incorporating uncertainty about species’ potential distributions under climate change into the selection of conservation areas with a case study from the Arctic Coastal Plain of Alaska     

Trevon Fuller  Sahotra Sarkar 《Biological conservation》2008,141(6):1547-1559

This analysis presents a conservation planning framework for decisions under uncertainty and applies it to the Arctic Coastal Plain of Alaska. Uncertainty arises from variable distributional shifts of species’ ranges due to climate change. The planning framework consists of a two-stage optimization model that selects a nominal conservation area network in the first stage and evaluates its performance under the climate scenarios in the second stage. The model is applied to eleven at-risk species in Alaska including the threatened Spectacled Eider and Steller’s Eider sea ducks and the polar bear. The 109th United States Congress and 2008 federal budget proposed opening for oil and gas development the “1002 Area” of the Arctic National Wildlife Refuge, which intersects the Plain. This analysis finds that, if Arctic Alaska experiences 1.5 °C of warming by 2040 (as predicted by the Intergovernmental Panel on Climate Change’s A2 scenario), then potential habitat will decrease significantly for eight of these at-risk species, including the polar bear. This analysis also shows that there is synergism between oil and gas development and climate change. For instance, climate change accompanied by no development of the 1002 Area results in an increase of potential habitat for Steller’s Eider. However, if development accompanies climate change, then there is a 20% decrease in that area. Further, this analysis quantifies the tradeoff between development and maintenance of suitable habitat for at-risk species.  相似文献   

Momordica charantia L. (Cucurbitaceae) floral volatiles causing attraction of Epilachna dodecastigma (Coleoptera: Coccinellidae)     

Nupur Sarkar  Saubhik Mitra 《国际虫害防治杂志》2017,63(2):138-145

Epilachna dodecastigma (Wied.) (Coleoptera: Coccinellidae) causes economic losses to bitter gourd, Momordica charantia L. (Cucurbitaceae) production in India and Bangladesh because adults feed on the leaves and flowers resulting death of the plant. This insect is currently controlled by insecticides, which are harmful to human health and environment. We studied the behavioral responses of E. dodecastigma females to floral volatiles and synthetic compounds comparable to floral volatiles in a Y-tube olfactometer to determine their potential for monitoring this pest. The gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detector (GC-FID) analyses of M. charantia floral volatiles revealed the presence of 20 compounds. Myrcene was predominant followed by methyl jasmonate and 1-octadecanol in floral volatiles. Epilachna dodecastigma females were attracted to floral volatiles by a Y-tube olfactometer bioassay. Females were attracted to individual synthetic 1-heptanol, sabinene, myrcene and ocimene at 16, 1, 20, and 8 µg/25 mL methylene chloride in a dose response bioassay, respectively, and hence, these compounds might be used for insect pest management strategies such as baited traps.  相似文献   

Salicylic acid mediated multi-pronged strategy to combat bacterial blight disease (<Emphasis Type="Italic">Xanthomonas axonopodis</Emphasis> pv. <Emphasis Type="Italic">punicae</Emphasis>) in pomegranate     

Ashis Maity  Jyotsana Sharma  Ananta Sarkar  Amarja K. More  Ram K. Pal  Vinayak P. Nagane  Arnab Maity 《European journal of plant pathology / European Foundation for Plant Pathology》2018,150(4):923-937

Pomegranate bacterial blight disease caused by Xanthomonas axonopodis pv. punicae is one of the most serious threat to the pomegranate industry in India. So far, the chemicals used to control this pathogen alone are less effective. In this article, an attempt was made to supplement chemical control through improving the systemic acquired resistance of plant using nutrients such as nitrogen (N) and salicylic acid (SA) as elicitor. The study revealed that foliar application of SA at the rate of 300 ppm increased above-ground dry mass of plant by 64.97%, improved chlorophyll content of leaves and resulted higher concentration of macro-elements and micro-elements, particularly Mn and Zn, in leaves. It also significantly increased the activities of nitrate reductase (NR), superoxide dismutase (SOD), catalase and peroxidase. However, the maximum response of SA was recorded when it was sprayed after soil application of N at 100% of the recommended dose. As a consequence, this combination recorded the least bacterial blight infection with average severity of 11.58% followed by without-N application under challenge inoculation of the pathogen. However, sustainable production cannot be realized without N application. The integration of this strategy for activation of defence mechanism of plant with the bactericide streptocycline resulted in further reduction of bacterial blight disease incidence and severity under field condition to very low levels (3.84% and 18.57% respectively).  相似文献   

Herbicide ready-mixes effects on weed control efficacy,non-target and residual toxicities,productivity and profitability in sugarcane–green gram cropping system     

Hirak Banerjee  Krishnendu Ray  Aritri Laha  Sukamal Sarkar  Sukanta Pal 《国际虫害防治杂志》2018,64(3):221-229

Weeds pose a major challenge at the initial stages of sugarcane and when uncontrolled cause high yield losses. This study was undertaken to define a better and cost-effective weed management strategy. We compared ametryn + trifloxysulfuron-sodium (hereafter referred to as trifloxysulfuron) ready-mixes with single applications of trifloxysulfuron, atrazine and 2,4-D for efficacy, non-target and residual toxicities, yield and profitability in a sugarcane–green gram rotation. Results showed that a density of 100 weeds m^?2 could reduce sugarcane yield by 18.4 t ha^?1. The ready-mix ametryn + trifloxysulfuron (1097.3 + 27.8) g a.i. ha^?1 applied 15 days after planting (DAP) caused reductions in weed density by 88.2%, 90.9%, and 90.3%, and weed biomass by 68.0%, 53.8%, and 56.2% compared to unweeded control at 30, 60, and 90 DAP, respectively. Consequently, the sugarcane yield, system productivity, and net returns were increased by 92.1%, 43.5%, and 1515%, respectively due to this ready-mix. It increased system productivity by 23%, 17.2%, and 22.7% compared to trifloxysulfuron, atrazine, and 2,4-D treatments, respectively. This ready-mix may be recommended in sugarcane. This would reduce weed seed bank and herbicide application cost by 50%, and prevent/delay weed shift and resistance.  相似文献   

Depth dynamics of soil N contents and natural abundances of 15N after 43 years of long-term fertilization and liming in sub-tropical Alfisol     

Avijit Ghosh  Brahma Swaroop Dwivedi  Dipak Ranjan Biswas  Mahesh Chandra Meena  Abhijit Sarkar 《Archives of Agronomy and Soil Science》2018,64(9):1290-1301

The aim of this study was to understand impacts of long-term (43 years) fertilization on soil aggregation, N accumulation rates and δ¹⁵N in surface and deep layers in an Alfisol. Soil samples from seven treatments were analysed for N stocks, aggregate-associated N in 0–30 cm and the changes in δ¹⁵N in 0–90 cm depths. The treatments were: unfertilized control (control); recommended N dose (N); recommended N and phosphorus doses (NP); recommended N, P and potassium doses (NPK); 150% of recommended N, P and K doses (150% NPK); NPK + 10 Mg FYM ha^?1 (NPK + FYM) and NPK + 0.4 Mg lime ha^?1 (NPK + L). Results revealed that plots under NPK + FYM had ~39% higher total N concentrations than NPK + L in 0–30 cm soil layers. In NPK + L, macro-aggregates had 35 and 11% and microaggregates had 20 and 9% lower δ¹⁵N values than NPK + FYM in 0–15 and 15–30 cm soil layers, respectively. However, plots receiving NPK + FYM had ~39% greater deep soil (30–90 cm) N accumulation than NPK + L. These results would help understanding N supplying capacity by long-term fertilization and assist devising N management strategies in sub-tropical acidic Alfisols.  相似文献   

Evaluation of Chemical Extraction Methods for Determining Plant-Available Potassium in Some Soils of West Bengal,India     

Suranjit Sarkar  Sanmay Kumar Patra 《Communications in Soil Science and Plant Analysis》2017,48(9):1008-1019

The effectiveness of eight chemical extraction methods was evaluated on 15 Indian soils for the prediction of plant-available potassium (K⁺) to Sudan grass (Sorghum vulgare var. sudanensis) grown in modified Neubauer technique. Average amounts of soil K⁺ extracted were in descending order: Morgan’s reagent > 0.5 M sodium bicarbonate (NaHCO₃) > neutral 1N ammonium acetate (NH₄OAc) > 1N nitric acid (HNO₃) > 0.02 M calcium chloride (CaCl₂) > 0.1N HNO₃ > Bray and Kurtz No.1> distilled water. The highest simple correlation with plant K⁺ uptake was obtained with NH₄OAc-K⁺ (r = 0.866**) and the lowest with CaCl₂-K⁺ (r = 0.45*). To develop the predictive models using stepwise regression, plant K⁺ uptake was used as the dependent variable and the extractable soil K⁺, pH, sand, silt and organic carbon (C) contents as the independent variables. Based on the final R², the NH₄OAc model was found to be the best predictor of plant-available K⁺ in the soils when used along with sand and organic C.  相似文献   

Pyrrolizidine alkaloid poisoning in yak.     

D B Mondal  U A Nandankar  T K Mohanty  S K Barari  R N Pal  M Sarkar 《The Veterinary record》1999,144(18):508-509

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Evaluation and impact assessment of culture‐based fisheries to enhance fish yield in small reservoirs in Odisha State,India     

Uttam K. Sarkar  Lianthuamluaia Lianthuamluaia  Debabrata Panda  Suman Kumari  Pranaya K. Parida  Gunjan Karnatak  Puthiyottil Mishal 《Fisheries Management and Ecology》2020,27(5):481-489

The present study investigates the success of stocking fingerlings of Indian major carps ‐Gibelion catla (Hamilton), Labeo rohita Hamilton and Cirrhinus mrigala Hamilton – to enhance fish yield in 58 small reservoirs in Odisha State, India. Fish stocking and yield data were collected from State Fisheries Department, Odisha. The relationships between area, stocking density and fish yield of different size groups of reservoirs were assessed using the Pearson correlation coefficient (r). Fish yield increased significantly (p < 0.05, t‐test) from 204 kg/ha/year in 2012–13 to 323 kg/ha/year in 2013–14 due to adoption of CBF. The corresponding per capita fish production increased from 398 kg fisher^?1 year^?1 to 702 kg fisher^?1 year^?1 benefitting more than 8,000 fisher households. Reservoirs in the size group 100–500 ha showed the highest response of fish yield with respect to stocking of fingerlings. The size of fingerlings at stocking and area of the reservoir had greater impact on enhancing fish yield. Stocking had a profound positive impact on fish yield. This study forms a baseline evaluation of the impact of stocking on small tropical reservoirs in India. It also recommends management measures and discusses issues, and the way forward for sustainable fisheries enhancement in small tropical reservoirs in eastern India.  相似文献   

Effect of LDPE microplastics on chemical properties and microbial communities in soil     

Kumuduni Niroshika Palansooriya  Liang Shi  Binoy Sarkar  Sanjai J. Parikh  Mee Kyung Sang  Sang-Ryong Lee  Yong Sik Ok 《Soil Use and Management》2022,38(3):1481-1492

The accumulation of plastics in the soil ecosystem poses an increasing environmental concern worldwide. However, little is known about the effect of plastic concentrations on soil properties and soil biota. In this study, we investigated the effect of low-density polyethylene (LDPE) microplastics (MPs) on the chemical and microbial properties of agricultural soil using a set of microcosm experiments. The soil was incubated for 100 days with LDPE at concentrations of 0%, 0.1%, 1%, 3%, 5%, and 7% at 25°C with 70% water-holding capacity. Along with soil chemical analysis, we conducted an analysis of soil microbial properties on the first day and again after 100 days of incubation. LDPE concentrations of ≥1% significantly (p < .05) decreased the pH but increased the electrical conductivity of the soil in comparison with the control (0% LDPE at 100 days). Increasing the LDPE concentration did not affect the soil exchangeable cation content or the available Pb concentration. Firmicutes were the most abundant phyla in the soil on the first day, whereas Proteobacteria, Firmicutes and Actinobacteria became dominant in all treatments after 100 days. An increasing LDPE concentration increased the abundance of Actinobacteria and decreased Proteobacteria. Principal component analysis demonstrated that only 7% LDPE was positively correlated with Actinobacteria, indicating that higher concentrations of LDPE contributed to the growth of this phylum. The findings of this study imply that MP contamination could affect soil chemical properties and microbial activity and that these effects primarily depend on MP concentrations in soil.  相似文献