排序方式： 共有34条查询结果，搜索用时 31 毫秒
11.
Fahimeh Westwood Kathy M. Bean Alan M. Dewar Richard H. Bromilow Keith Chamberlain 《Pest management science》1998,52(2):97-103
[14C]Imidacloprid was applied to pelleted seeds of sugar beet which were then grown in pots of field soil. Leaves, roots and soil were analysed at intervals up to 97 days after planting and the distributions of parent compound and of several metabolites were quantified. At the first sampling, 21 days after application, parent imidacloprid was the main compound found in the leaves and its concentration averaged 15·2 μg g-1 fresh weight. By the 25-leaf stage, 97 days after sowing, the concentration of parent compound in the leaves had fallen to an average of 0·5 μg g-1; the metabolites and parent compound in the leaves then represented respectively 44·5% and 4·5% of the total applied radioactivity. In the root at 97 days, parent imidacloprid and its metabolites together accounted for only 0·1% of the applied activity, whilst in the soil there was 23% of parent compound and 4% as metabolites. The persistence of both parent imidacloprid and the olefinic metabolite, which has recently been shown to have higher aphicidal activity than the parent imidacloprid, explains the prolonged control of aphids observed with imidacloprid in both glasshouse and field trials. © 1998 SCI. 相似文献
12.
In this study starch-montmorillonite/polyaniline (St-MMT/PANI) nanocomposite was synthesized by chemical oxidative polymerization of aniline in the presence of starch-montmorillonite nanocomposite dispersion. The prepared ternary nanocomposite was characterized using FT-IR, XRD, SEM, TGA and TEM techniques. XRD patterns combined with TEM results confirmed the intercalation of MMT in the starch matrix. SEM micrographs revealed the growth of polyaniline over the surface of the St-MMT nanocomposite. The St-MMT/PANI nanocomposite was used for the adsorption of a reactive dye. Batch removal experiment results showed complete removal of dye in a very short contact time. Further investigations indicated that the removal mechanism was based on both the adsorption and electrostatic attraction between nanocomposite and dye molecules. The experimental data were well fitted to the Langmuir isotherm and pseudo-second-order kinetic model. The adsorption capacity of reactive dye on St-MMT/PANI nanocomposite was 91.74 mg g?1. All these results demonstrated the effectiveness of the hybrid system as an efficient adsorbent for removal of reactive dyes from textile effluents. 相似文献
13.
Mohammad Ali Behdani Majid Jami Al-Ahmadi Hamid-Reza Fallahi 《Journal of Crop Science and Biotechnology》2016,19(1):71-76
In this study saffron biomass partitioning was investigated in the research station of the Saffron Research Group, University of Birjand, Iran during 2009 - 2010. Plant sampling was done 25 times during the crop growth cycle. In each sampling date, the amounts of corm dry weight, root dry weight, root length, leaf dry weight, leaf area, bud number, bud dry weight (nodes on the surface of the corm), and flower weight were measured. Finally, different regression models were tested for predicting biomass partitioning in saffron. The cubic polynomial model was found to be the best for predicting biomass changes in most saffron organs (R 2 = ~74%). Total corm dry weight showed a decreasing trend up to the 120th day of plant growth and then increased until the end of the life cycle (mid-May). However, different trends were observed for root and leaf dry weights. Root and leaf dry weight increased up to the 120th and 150th day of the plant growth cycle, respectively, followed then by decreasing trends. Therefore, in the early growing season, leaves and root systems were developed using mother corms reservoirs, but at the end of the growth cycle replacement corms were grown by translocation of reservoirs from other saffron organs. In addition, the number and dry weight of buds had increasing trends during 160 days of measurement from the beginning of the growing season. The total length of roots and leaf area increased up to the middle of the growth cycle (Feb. 10) and then decreased. Moreover, saffron flower yield showed a rapid increasing trend in the first phase of the flowering period and then declined with a slower trend during the second flowering phase. 相似文献
14.
Jami MJ Salehduost A Negarestan H 《Pakistan journal of biological sciences: PJBS》2010,13(20):993-999
Coral reefs are specialized communities that develop clear, well-lit tropical and subtropical water; they provide shelter and canopy for great variety of organisms, living in mean temperature of 20 degrees C. Coral Bleaching and mortality have been associated with elevated seawater temperature. The aim of the study was to investigate coral bleaching and evaluate health condition of the corals. Distribution of coral reefs around Kish Island was determined by the Timed Swim (TS) technique. This survey carried out in 2 times (May and October, 2009) in 2 depths of 3-5 m and 6-10 m. Two Divers swam in constant speed for a set amount of time in three dive sites. The timed swim survey around the Kish Island showed that the most healthy live hard coral assemblages were found in the site called Persian Gulf seaport, whereas the greatest percentage of bleached corals were located in Jurassic Park station, located at the southeast of the Island. Branching corals (Acropora sp.) were bleached among all 3 stations and no sign of recovery could be detected. In Big coral site suitable substrate for accumulation of living organisms including Echinometra mathaie (sea urchin) existed due to presence of great amount of algae on dead corals and rocks. Based on the observation, it seems that the cause of reef destruction in Kish Island fall in to two categories, natural and human impacts. 相似文献
15.
Mahin Rafieipour Alireza Motallebi-Azar Nasser Mahna Habib Davati Kazemnia Samaneh Kazemiani Fahimeh Yarmohamadi 《Russian Agricultural Sciences》2011,37(5):385-391
In this research, the factors affecting seed production of six landraces (Sefid-e-Ghom, Germez-e-Azarshahr, Dorcheh-e-Isfahan,
Tarom, Germez-e-Kazeroon, Sefid-e-Abarkooh) and a foreign cultivar (Yellow Sweet Spanish as a control) were evaluated in a
randomized complete block design experiment with three replications. Results indicated significant differences between genotypes
regarding some of the traits. Seed stalks were emerged in Tarom and Yellow Sweet Spanish earlier than other landraces. Flowering
of Germez-e-Kazeroon and Tarom were the first and last, respectively. Also, ripening of seed in Germez-e-Kazeroon and Yellow
Sweet Spanish was earlier and later than other landraces, respectively. The number of seed stalks/plant and seed yield/ha
were increased while increasing in bulb size from 5 to 7 cm. Among the landraces, Sefid-e-Ghom and Germez-e-Azarshahr showed
the highest and lowest number of seed stalks/plant, respectively. Sefid-e-Ghom, also, showed the highest seed yield/inflorescence,
/plant and/ha. Although the differences were not significant statistically. Relationships between traits showed that seed
yield/plant and /ha was a positively correlated with the number of seed stalks/plant. Genotypes were grouped in three clusters
using Ward method. 相似文献
16.
Nemati E Ghanbarpour F Taheri S Einollahi B 《Pakistan journal of biological sciences: PJBS》2008,11(6):910-914
The aim of this study is to document the prevalence of HTN and characterize risk factors associated with HTN in Iranian hemodialysis patients. Three hundred and thirty seven HD patients from 5 university based HD centers around Iran were enrolled in the study. Urea reduction ratio was calculated using formula: 100 * (1-(urea before HD/urea after HD)). Pearson Chi-square test, independent sample t-test and one way ANOVA were used for evaluations, where appropriate. Multivariate logistic regression model was used for defining independent risk factors. Two sided p < 0.05 were considered significant. Patients with diabetes mellitus and hypertension as causes of ESRD significantly were more likely to have hypertension before and after dialysis (p < 0.05). Patients with conventional thrice weekly dialysis (compared to twice), hemodialysis duration of more that 6 months, acetate type of dialysate, ESRD cause when diabetes mellitus and hypertension, were significantly associated with having pre-HD hypertension. We also found that hemodialysis center of the capital city had a significant better measures compared to other cities (p < 0.05). This study revealed a relatively acceptable prevalence of hypertension in our HD population. Nevertheless, because of higher prevalence of HTN in HD centers out of capital city, it seems necessary that we should urgently pay more attention in promotion of these centers toward achieving better outcome with implementing strict guidelines to follow. 相似文献
17.
Leonardo S. S. Oliveira Muhamad A. Saha Fahimeh Jami Rianza Asfa Maggie V. Maretha Jaliaman Sipayung Marthin Tarigan Alvaro Duran 《Forest Pathology》2023,53(5):e12825
Powdery mildews are biotrophic ascomycetes that do not typically kill their hosts, but instead interfere with normal plant growth. In Indonesia, white powdery spots were observed forming on the upper part of fully developed leaves of Eucalyptus pellita planted in sand beds of a clonal nursery. Thus, this study aimed to identify the causal agent of eucalypt powdery mildew in Indonesia as well as to develop control strategies to better manage the disease. Pathogen identification was based on morphology, molecular characterization of DNA sequencing the ITS region and pathogenicity test. In addition, considering that some powdery mildews are inhibited by free moisture on leaves, efficacy of foliar watering was tested for disease control. Phylogenetic analyses showed that isolates collected from infected eucalypt plants grouped together with other sequences of the Erysiphe elevata clade with bootstrap support of 99%; a similar result was also confirmed by morphological observations. Pathogenicity of powdery mildew on eucalypt plants was confirmed through artificial inoculation, thus fulfilling the Koch's postulates. For disease control, foliar watering reduced the incidence of powdery mildew on mother plants. The reduction of the disease incidence began to be more evident at 2 weeks after trial establishment, and in the fourth week, the incidence was below 10% in all three treatments, while the control was above 20%. Therefore, we concluded that E. elevata is the causal agent of powdery mildew in Indonesia and that one application of foliar watering per week was enough to minimize the disease impact in the nursery. 相似文献
18.
Genetic Resources and Crop Evolution - Citrus plants are one of the most important fruit plants which are consumed all over the world. The breeding of these valuable fruit plants is based on... 相似文献
19.
Alireza Motallebi-Azar Samaneh Kazemiani Fahimeh Yarmohamadi 《Russian Agricultural Sciences》2013,39(2):112-116
In order to evaluate of using microtubers for conservation of potato germplasm, the main effects of sucrose, mannitol and PEG on percentage of microtuber initiation and formation, size and fresh weight of microtuber were studied. PEG decreased production and weight of microtubers, whereas higher concentrations of sucrose promoted microtuber production, microtuber size as well as microtuber fresh weight. Increasing of sucrose concentrations were improved efficiently in vitro microtuber production without negative side effects. Addition of mannitol to all media was increased microtuberization than media containing PEG. So, alcoholic sugars such as mannitol increased microtuberization, but after 5 weeks, microtuberization in media supplied with sucrose was more than the mannitol. Such studies might help to reduce the cost of production of virus free potato seed from different cultivars. 相似文献
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