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This paper presents the simultaneous measurement of atmospheric concentration of gaseous NH3, SO2 and NO2, and particulate NH 4 + released from the mining activities of coal-mine area, Tirap colliery, Margherita (Assam). Gas samples were collected by impinger method and were analyzed colorimetrically. The vapor-phase concentration of NH3, SO2, and NO2 range between 4.7?C40.03, 1.47?C6.14, and 1.92?C2.40???g/m3. The NH 4 + concentration in PM10 and PM2.5 ranges between 0.02?C0.07 and 0.008?C0.03???g/m3, respectively. Moderately high concentrations of NH3 and SO2 on the first day were due to the coal-burning activity near the sampling site, while the low concentration of NO2 is due to less vehicle density near the sampling point. All the observed concentrations are below than those reported for the urban areas and the prescribed limit fixed by National Ambient Air Quality Standard, India. Study indicates that ammonia is the major neutralizing agent for sulfate and nitrate ions present in the particulate matter during mining activities.  相似文献   
2.
With continuous outbreaks of stripe rust (Puccinia striiformis f. sp. tritici) epidemics and rapid breakdown of deployed resistance in bread wheat (Triticum aestivum L.) cultivars in North West Plains Zone (NWPZ) in India warrant knowledge and deployment of new and durable sources of resistance to stripe rust. Bread wheat cultivar PBW 343, until recently the most widely cultivated wheat variety in India, is now highly susceptible to stripe rust (score 9 on a 1–9 scale), whereas PBW 621 (score 5.05–5.65) and HD 2967 (score 5.40–6.20) show low levels of resistance. We conducted an experiment, spanning three crop seasons (2013–2014 to 2015–2016), in which parental lines, F1 and F2 populations, F3 and F4 families from two bread wheat crosses, PBW 621/PBW 343 and HD 2967/PBW 343 were generated and evaluated for stripe rust resistance against a virulent pathotype. While the F1 revealed partial dominance, the segregation pattern for stripe rust resistance in F2 and F3 showed transgressive segregation for resistance in both crosses. Chi-square analysis indicated that resistant segregants possessed two genes, one contributed by PBW 621 or HD 2967 (depending on the cross) and the other, unexpectedly but obviously, came from the most susceptible cultivar, PBW 343. Possible genetic mechanisms for this residual resistance and implications for breeding programs are discussed.  相似文献   
3.
Accelerated ageing test methodology is valid and widely accepted procedure for estimating the lifetime of isotropic homogeneous polymeric materials. However for non-isotropic and heterogeneous polymeric compounds such as glass reinforced epoxy (GRE) pipes, accelerated ageing test methodology has not been much investigated. Various standards such as ASTM D 3681, ASTM D 5365 are being used to estimate the lifetime of GRE pipes using regression analysis which is time consuming, and requires large number of test specimens and fixtures specific to pipe dimensions. Accelerated ageing test methodology can be a viable method for estimating the lifetime. The research on accelerated test methodology as a vital tool to determine the lifetime of GRE pipes has been limited. The major concern for using accelerated ageing test methodology is primarily due to the degradation kinetics of the anisotropic composite materials which may not be governed by the Arrhenius principle. The present study on the estimation of lifetime of GRE pipes in extreme acidic and alkaline medium reveals that degradation of the composite pipe follows the Arrhenius principle and the degradation mechanism can be described by first order reaction kinetics. The degradation rate, the temperature dependence of the degradation rate and lifetime of the glass reinforced epoxy pipes in extreme acidic and alkaline medium as found in the current study are presented here, along with the morphological study of aged and un-aged GRE pipes.  相似文献   
4.
Interspecific interactions play an important role in ecosystem functioning. Several biocontrol agents are being introduced for the control of invasive species like the aquatic macrophyte, waterhyacinth, Eichhornia crassipes, in the hope of improving the eco-friendly natural control mechanism. Due to their overlapping niches, interspecific interactions among the biocontrol agents is high and there is a paucity of information on possible positive or negative impact they may have on each other hence affecting the biocontrol. Therefore studies on their interaction become even more important. In order to understand such possibilities, three potential fungi, Fusarium oxysporum (FO), F. roseum (FR), Paradendryphiella salina (PS) and two host-specific arthropods Orthogalumna terebrantis (OT) and Neochetina bruchi (NB) were applied on water hyacinth plants singly and in various combinations (OT, NB, FO, FO + OT, FO + NB, FR, FR + OT, FR + NB, PS, PS + OT, PS + NB). Observations were made on percentage damage caused by these agents to water hyacinth. Biocontrol agents applied in combination had cumulative impact on the target weed. FO + NB and FO + OT treated plants showed enhanced damage percentage of about 90%, after 120 h. But FR + NB and PS + NB treated plants were far less damaged compared to when these agents were applied separately. PS also had a repelling effect on NB. Results of such interactions are often variable and less predictable, especially under field conditions. These results demonstrate the need for studies on biotic interactions among biocontrol agents, prior to release of the biocontrol agents of weeds.  相似文献   
5.
Genetic Resources and Crop Evolution - Gradual deterioration in water resources and unpredictable distribution pattern of annual precipitation amount are major threats having drastic effects on...  相似文献   
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