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161.
Rapid detection technologies with high sensitivity and selectivity for plant pathogens are essential to prevent disease spread and minimize losses to assure optimal productivity and food security. Traditional laboratory techniques such as microscopy and culture are time-consuming, labour intensive and require complex sample handling. Immunological and molecular techniques have advanced but have some issues related to rapidity, signal strength and instrumentation. The integration of immunological and molecular diagnostics with nanotechnology systems offers an option where all detection steps can be accommodated on a portable miniaturized device for rapid and accurate detection of plant pathogens. The sensitive nature of functionalized nanoparticles can be used to design phytopathogen detection devices with smart sensing capabilities for field use. This review summarizes the current status and future prospects of nanotechnology for detection and diagnosis of plant pathogens. 相似文献
162.
Rahul Bhadouria Pratap Srivastava Rishikesh Singh Sachchidanand Tripathi Hema Singh A. S. Raghubanshi 《The Environmentalist》2017,37(1):88-100
The current anthropogenic activities and climate change are increasingly becoming a growing global concern for dry tropical forests. Worldwide, these ecologically important forests have degraded considerably since the past few decades due to such factors. These factors have harmful consequences on the vegetation structure and diversity especially tree seedlings, which may further aggravate climate change. Generally, the vegetation recovery is very slow and unpredictable in the dry tropics due to complex interaction among tree seedling, site (particularly, soil) and climatic conditions. We inculcated that a better understanding of the behavior of individuals of different tree species at seedling stage in dry forests is of immense importance. It is increasingly being recognized for explaining and managing the future composition of plant communities under changing environmental conditions. In this regard, the multi-factorial interaction studies under various resource–disturbance combinations are needed in dry tropical ecosystems to understand the: (1) impact of relative variability in resources and disturbances on the responses of tree seedlings of native species and (2) how the later relates to distinct functional and life history traits of the individual tree species. Most importantly, such studies would improve our limited understanding of how variation (natural and man-made) in nutrient availability, under the influence of other local environmental factors (such as water, light, grass competition, herbivory, fire, allelopathy and enhanced CO2 conditions), would affect the dynamics of dry tropical forest community. It may help in the proper management of these forests. Moreover, it may prove helpful in the current climate change scenario, as change in forest community dynamics may have consequences on soil C sequestration and CO2 efflux at global scale. 相似文献
163.
Agricultural production in the state of Alabama, USA, is mostly rain-fed, because of which it is vulnerable to drought during
growing season. Since Alabama receives a significant portion of its annual precipitation during winter months, the goal of
this study was to evaluate the feasibility of water withdrawal from streams during winter months for irrigation in the growing
season. The Soil and Water Assessment Tool (SWAT) was used to estimate the quantity of water that can be sustainably withdrawn
from streams during winter high flow periods. The model was successfully calibrated and validated for surface runoff, base
flow, and total stream flow. The stream flows generated by the model at several locations within the watershed were then used
to examine how much water can be sustainably withdrawn from streams of various orders (first, second and third). Although
there was a considerable year-to-year variability in the amount of water that can be withdrawn, a 16-year average showed that
first, second, and third order streams can irrigate about 11.6, 10.3, and 10.6% of their drainage areas, respectively. The
percentage of drainage area that can be irrigated was not a function of stream order. 相似文献
164.
Tonk S Bartarya R Maharaj Kumari K Bhatnagar VP Srivastava SS 《Journal of environmental biology / Academy of Environmental Biology, India》2006,27(1):103-105
Leaves of Artemisia annua linn. and Azadirachta indica were extracted in petroleum ether and hexane respectively by different methods of extraction i.e. cold extraction, reflux extraction and soxhlet extraction. The crude extract obtained was tested against third instar larvae of Anopheles stephensi. On comparison of larval mortality of crude extract obtained by these three methods, both soxhlet and reflux extraction method showed 100% mortality at 200 ppm after 48 hr in case of A. annua. However LC50 (20 ppm) value of crude extract obtained by soxhlet extraction showed better results than reflux extraction (35 ppm) method after 72 hr. In case of A. indica, crude obtained by soxhlet showed 100% mortality (after 48 hr) at 250 ppm and LC50 of 69 ppm at 72 hr. Reflux extraction does not show any appreciable mortality even at 250 ppm concentration. 相似文献
165.
Srivastava A 《Journal of environmental radioactivity》2005,78(1):113-121
This paper reports on radon concentrations in dwellings from fifty different locations of India. The incorporated data were obtained using the passive solid state nuclear track detector technique. The estimated geometric mean value for India is 67.1 Bq m(-3). Chuadanga in Bangladesh had the lowest observed indoor radon concentration of 27.3 Bq m(-3) and Una in the northern part of India had the highest concentration of 281.5 Bq m(-3). This paper discusses the national geometrical mean value in terms of the national geometric mean values of other countries and also in terms of the geological influence. The estimated indoor radon levels are compared with the indoor radon levels as recommended by the International Commission on Radiation Protection (ICRP). It was observed that there are several locations in India where dwellings have higher indoor radon levels than the ICRP recommended value and requires some sort of intervention from regulating authorities. The mean value for indoor radon level given in the report of UNSCEAR 2000 for India needs to be revised. 相似文献
166.
Srivastava A 《Environmental monitoring and assessment》2005,107(1-3):363-373
The variability of pollutants is an important factor in determining human exposure to the chemicals. This study presents the result of investigation of variability of Volatile organic compounds (VOCs) in urban area of Delhi, capital of India. Fifteen locations, in five categories namely residential, commercial, industrial, traffic intersections and petrol pump were monitored for one year every month during peak hours in morning and evening. Measurement focused on target VOCs as defined by USEPA. Variability was divided into measurement, spatial, temporal and temporal–spatial interaction components. Temporal component along with temporal–spatial interaction were found to be the major contributors to the variability of measured VOC concentrations. Need of continuous monitoring to capture short–term peak concentration and averages is evident. 相似文献
167.
168.
169.
Treatment with 40% and 80% of the LC50 (24h) of the pyrethroid permethrin after 24h exposure causes significant reduction in the activity of lactate dehydrogenase and cytochrome oxidase and enhanced the succinate dehydrogenase activity in the tissues of the freshwater fish Channa striatus. The results indicate that permethrin blocks aerobic as well as anaerobic metabolism in the exposed fishes. 相似文献
170.
Gopal K Srivastava SB Shukla S Bersillon JL 《Journal of environmental biology / Academy of Environmental Biology, India》2004,25(4):469-475
Various options are applicable for the removal of water pollutants included reverse osmosis, ion exchange, coagulation, co-precipitation, catalytic reduction, herbal filtration, electrodialysis and adsorption. This paper deals with the sorption phenomena for the removal of pollutants from drinking water. Attempts have been made to use low cost sorbents developed by pretreatment/activation/impregnation with alkalis, acids, iron oxide, manganese dioxide, ferric chloride, alum, lime, aluminum salts with natural products/indigenous minerals viz. activated alumina, activated carbon, groundnut husk, saw dust, chemically coated sand, fly ash, zeolites, clay minerals and other plant products. Application of Freundich and Langmuir isotherms were used to assess the adsorption capacity. Equilibrium isotherms were determined at optimum temperature and pH to characterize the sorption process. Statistical parameters such as mass transfer coefficients, multiple regression analysis were applied to establish the mechanism. It is suggested that the characterization of suitable, and exhausted sorbent through the application of fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF) is essential to establish its surface bonding. Scope for safety evaluation and risk assessment to human and biosphere may provide the guideline and predication to the regulatory agencies for its sustainable use and safe disposal The ecotoxicological assessment of the leachates and low cost removal technology are discussed in this paper. 相似文献