首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:从到   被引次数:从到   他引次数:从到 提示：输入*表示无穷大
全文获取类型
  收费全文   21篇
  免费   0篇
专业分类
基础科学   1篇
  5篇
综合类   2篇
农作物   3篇
畜牧兽医   3篇
园艺   1篇
植物保护   6篇
出版年
  2023年   1篇
  2022年   1篇
  2021年   2篇
  2019年   2篇
  2018年   2篇
  2016年   2篇
  2014年   1篇
  2013年   5篇
  2012年   2篇
  2011年   1篇
  2010年   1篇
  2007年   1篇
排序方式： 共有21条查询结果，搜索用时 15 毫秒
11.
Abstract

The aim of this study was to investigate the influence of different compositions of nitrogen (N) sources on yield and nutritional quality in potato cultivars (Solanum tuberosum L.). The experiment used a factorial arrangement as two factors in randomized complete block design. Factor (A) was nitrogen sources: control, 75% M?+?25%V, 50% M?+?50%V, 100% M, where M plots received nitrogen from mineral fertilizer and V plots received nitrogen from vermicompost. Factor (B) was potato cultivars (Sante and Savalan). In Sante cultivar, 75% M?+?25%V produced the highest total and marketable yield. In Savalan, cultivar application of vermicompost in 75% M?+?25%V and 50% M?+?50%V increased significantly total and marketable yield as compared with 100% M. Application of vermicompost significantly decreases tuber nitrate content and increases nitrogen-use efficiency. In Savalan, cultivar 50% V?+?50%M and in Sante cultivar 75% V?+?25%M can effectively be used for improving yield and nutritional quality of tuber.  相似文献   
12.
The field strain of Anopheles stephensi, the main malaria vector in south of Iran, was colonized in laboratory and selected with DDT and dieldrin in two separate lines for 3 generations to a level of 19.5- and 14-fold for DDT and dieldrin resistance, respectively. Synergist tests with chlorofenethol (DMC) and piperonyl butoxide (PBO) on the selected strains indicated that dehydrochlorination and oxidative detoxification might be the underlying mechanisms involved in the resistance to dieldrin and DDT in selected strains. DDT selection decreased susceptibility to DDT and pyrethroids including lambdacyhalothrin, permethrin deltamethrin and cyfluthrin. The result also showed that selection with dieldrin caused negative and positive cross-resistance to pyrethroid and fipronil, respectively. Based on these results, it can be concluded that besides metabolic resistance mechanisms, other factors such as mutation in γ aminobutyric acid (GABA) and voltage-gated sodium channels (Kdr) might be involved.  相似文献   
13.
  相似文献   
14.
Cucumber mosaic virus (CMV) is one of the most important plant viruses responsible for sharp reductions in the production of many cultivated plants. Activities of antioxidant enzymes, photosynthetic capacity, proline and total soluble carbohydrates (TSC) content were measured in the leaves of tomato (Solanum lycopercicum cv. Falat) plants treated with phytohormones (salicylic and jasmonic acids and their combination) and inoculated with CMV at 0, 1, 2, 4, 6, 8, and 15 days after the treatments. Based on the results, catalase (CAT) activity decreased in the healthy and infected plants, but peroxidase (POD) activity increased in the CMV-infected plants signifying that POD is more active in H2O2 scavenging in tomato. Because the hormone treatments inhibited the reduction in the enzyme activity, it may be considered as a controlling method against CMV. Superoxide dismutase (SOD) activity was lower in the control until 6 days post inoculation (dpi), but increased after 8 dpi. The infected plants and the hormone-treated plants showed an increased SOD activity from 0 to 15 dpi. Phenylalanine ammonia lyase (PAL) activity also increased in all the treatments over the time period (0-15 dpi). Net photosynthesis (NP) rate and chlorophyll content decreased under the virus infection and hormone treatment, whereas control plants had the highest NP and chlorophyll content. Proline accumulation occurred in the infected and hormone- treated plants, but TSC content decreased in comparison to the control. Reduction of TSC content was not significant in the hormone and virus- treated plants. Expression of CMV coat protein gene (CMV-CP) was decreased by approximately 34% in SA+JA+CMV treatment in comparison to the CMV-infected plants. In conclusion, CMV had harmful effect on physiological traits of tomato plants, but hormone application induced resistance. This resistance may be accomplished through the combination of both hormone-related signaling pathways which likely established a strong resistance network together.  相似文献   
15.
Background:Gastric cancer is the fourth most common human malignancy and the second reason for cancer morbidity worldwide. LncRNA HOTAIR has recently emerged as a promoter of metastasis in various cancer types, including GC, through the EMT process. However, the exact mechanism of HOTAIR in promoting EMT is unknown. Aberrant expression of the miR-200 family has been linked to the occurrence and development of various types of malignant tumors. This study investigates the correlation between the HOTAIR and miR-200 family gene expression patterns in GC cell lines. We investigated the miR-200 and HOTAIR due to their common molecular features in the EMT process. Methods:AGS and MKN45 cell lines were transfected with si-HOTAIR, along with a negative control. The effect of HOTAIR knockdown was also analyzed on cell viability and also on the expression of miR-200 family members, including miR-200a, -200b, and -200c, in cell lines using qRT-PCR. Statistical analysis was performed to find the potential correlation between the expression level of HOTAIR and miRs. Results:Our results showed significant increased miR-200 family expression level in transfected AGS and MKN45 GC cells (fold changes > 2; p < 0.001). Moreover, a negative correlation was observed between HOTAIR and miR-200 expression levels in GC cell lines (p < 0.05). Conclusion:Our findings showed a significant association between miR-200 family and HOTAIR expression levels in GC cell lines. Taken together, the HOTAIR-miR-200 axis seems to play a vital role in human GC, suggesting a potential therapeutic target in future GC treatment. Key Words: Gene expression, Long noncoding RNA, HOTAIR, MicroRNAs  相似文献   
16.
The management of irrigated agricultural fields requires reliable information about soil hydraulic properties and their spatio-temporal variability. The spatial variability of saturated hydraulic conductivity, Ks and the alpha-parameter αvG-2007 of the van Genuchten equation was reviewed on an agricultural loamy soil after a 17-year period of repeated conventional agricultural practices for tillage and planting. The Beerkan infiltration method and its algorithm BEST were used to characterize the soil through the van Genuchten and Brooks and Corey equations. Forty field measurements were made at each node of a 6 m × 7.5 m grid. The soil hydraulic properties and their spatial structure were compared to those recorded in 1990 on the same field soil, through the exponential form of the soil hydraulic conductivity given by the Gardner equation, using the Guelph Pressure Infiltrometer technique. No significant differences in the results obtained in 1990 and 2007 were observed for either particle-size distribution or dry bulk density. The mean value of αvG-2007 was found to be identical to that of αG-1990, while that of Ks-2007 was significantly smaller than that of Ks-1990. In contrast to the Gardner equation, the van Genuchten/Brooks and Corey expression was found to be more representative of a well-graded particle-size distribution of a loamy soil. The geostatistical analysis showed the two parameters, Ks and αvG-2007, were autocorrelated up to about 30 and 21 m, respectively, as well as spatially positively correlated within a range of 30 m. Despite the difference in the mean values of Ks between the two studies, the spatial structures were similar to those found in the 1990 experiment except for the covariance sign. The similarity in autocorrelation ranges indicate that the spatial analysis of soil hydraulic properties is independent of the infiltration methods (i.e., measurement of an infiltration flux) used in the two studies, while the difference in the covariance sign may be linked to the use of two different techniques of soil hydraulic parameterization. The covariance values found in the 2007 campaign indicates a positive relationship between the two parameters, Ks and αvG-2007. The spatial correlations of soil hydraulic parameters appear to be temporally stabilized, at least within the agro-pedo-climatic context of the study. This may be attributed to the soil textural properties which remain constant in time and to the structural properties which are constantly renewed by the cyclic agricultural practices. However, further experiments are needed to strengthen this result.  相似文献   
17.
A field study was carried out at the Indian Agricultural Research Institute, New Delhi, India, for three crop years (2000–2001 to 2003–2004) to find out the effect of cropping systems on the production and chemical and biological properties of soil. Rice-potato-mungbean cropping system gave 59–89% higher productivity, 30–46% higher protein yield, 18–38% higher energy output and resulted in 7–16% higher available P, 60% higher fungi population, 15% higher actinomycetes population, 14% higher microbial biomass and 3% higher CO2 evolution in soil than rice-wheat cropping system. Rice-rapeseed-mungbean cropping system also gave 12–15% higher productivity, 19–26% higher protein yield and resulted in 11–18% higher available P, 65% higher fungi population, 22% higher actinomycetes population, 12% higher microbial biomass and 2% higher CO2 evolution in soil than rice-wheat cropping system. However, the rice-potato-mungbean cropping system was significantly superior to the rice-rapeseed-mungbean cropping system in productivity, protein yield and energy output and thus recommended as in alternative to rice-wheat cropping system.  相似文献   
18.
Field experiments were conducted at the Indian Agricultural Research Institute, New Delhi, India for three years from 2001–2002 to 2003–2004 to study the relative efficiency of diammonium phosphate (DAP) and mussoorie rock phosphate (MRP) in a rice-potato-mungbean cropping system. Phosphorus application significantly increased productivity, protein yield and energy output of rice-potato-mungbean cropping system and resulted in an increase in 0.5 M sodium bicarbonate (NaHCO3) extractable phosphorus (P) content in soil. The MRP at 35 kg P ha?1 was at par with 17.5 kg P ha?1 as DAP in terms of productivity, protein yield, and energy output but significantly superior in terms of PSB population in soil. Phosphorus balance (application – crop removal) was generally more positive for MRP than DAP and the highest with an application of 52.5 kg P ha?1 as MRP. Present study indicates that P requirement of a rice-potato-mungbean cropping system can be met with 76–79% higher dose of MRP as compared to DAP.  相似文献   
19.
This research is performed for evaluating the morphogenesis responses of thin cell layers (TCL) of alfalfa (Medicago sativa cv. Karysary) hypocotyls. TCLs (0.1–0.5 mm) were obtained from sterile hypocotyls that were cultured to SH medium containing various combinations of 2,4-D and kin (0, 0.5, 1, 1.5 and 2 mg/l). Unexpectedly, the percentage of callus induction (PCI) and Callus diameter (CD) were not affected by different concentrations of 2,4-D and kin. PCI was 100% without any correlation to hormonal combinations. Significantly the difference between concentrations of 2,4-D and kin for percentage of somatic embryogenesis (PSE) was observed (p < 0.01) so that, the maximum PSE occurred with 1.5 mg/l 2,4-D and without kin. The 2,4-D and kin interaction was not significant for PSE showing that each of these hormones affected by PSE independently. The number of embryoids (NE) was significantly different on the various concentrations of 2,4-D (p < 0.05) and maximum NEs were observed on 1.5 mg/l 2,4-D and without kin.  相似文献   
20.
Nanofibers have a great potential for enzyme immobilization application due to their large surface area to volume ratio besides their porous structure. In this work, we produce polymethyl methacrylate (PMMA) nanofibers via electrospinning method in dimethylformamide (DMF) as solvent. Thereafter, we employ a chemical method on final PMMA nanofiberous web to covalently immobilize acetylcholinesterase (AChE) enzyme on membrane surface. Morphology and tensile properties of nanofibers are studied as first steps of characterization to make sure of obtaining a properly stable membrane for enzyme carrying application. Thereafter, the stability and activity of immobilized enzymes as two main characteristic parameters are tested and reported for different applications such as biosensor manufacturing.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号