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:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   18篇
  免费   1篇
  国内免费   1篇
农学   1篇
  1篇
综合类   4篇
农作物   1篇
水产渔业   3篇
畜牧兽医   2篇
植物保护   8篇
  2020年   1篇
  2016年   1篇
  2014年   2篇
  2007年   3篇
  2005年   2篇
  2003年   1篇
  2002年   3篇
  2000年   1篇
  1999年   1篇
  1996年   1篇
  1970年   1篇
  1969年   3篇
排序方式: 共有20条查询结果,搜索用时 15 毫秒
1.
Summary. Tracer studies using single drops of solutions containing 3–amino-1,2,4–triazole-5–14C (aminotriazole-14C) or 2,2–dichloropropionic acid-2–14C (datapon-14C) revealed that in couch plants (Agropyron repens (L.) Beauv.) growing under field conditions in the autumn and at the stage where the aerial shoots were 40–50 cm long, both compounds moved in both symplast and apoplast. Dalapon was less mobile in the symplast than aminotriazole and only negligible amounts of dalapon were translocated to the rhizomes. The nodes of the treated shoots appeared to act as barriers to translocation, a phenomenon more pronounced for dalapon than for aminotriazole.
Application to a basal green leaf led to a more uniform distribution of the compounds within plants and rhizomes than when the application was made to the youngest fully-expanded leaf.
In couch plants with aerial shoots 10–15 cm long treated in the stubble, the distribution of both aminotriazole and dalapon was mainly restricted to the treated shoots. Even 15 days after application only trace amounts of radioactivity could be found in the rhizomes and untreated shoots.  相似文献   
2.
This study aimed to detect the genetic variability in Leptin and Pit‐1 genes using polymerase chain reaction–restriction fragment length polymorphism and DNA sequencing also to explore their possible associations with reproductive and productive traits of Egyptian buffaloes. Regarding Leptin gene, three genotypes (AA, AG and GG) were identified with frequency of 0.54, 0.40 and 0.06, respectively, and the genotypes were distributed according to the Hardy–Weinberg equilibrium. Allele A was comparatively higher than G with frequency of 0.74 and 0.26, respectively. For Pit‐1 gene, the association could not be performed due to the monomorphism (BB). The results showed that AA genotypes were found to be superior in most of production and reproduction traits. AA genotypes yielded more milk (2332.34 kg, p = 0.04) with higher fat% (6.10, p = 0.004) and fat yield (155.75 kg, p = 0.06), reach peak milk production at 42.19 days and required 2.19 services for conception in comparison with GG genotypes. Birthweight of animals with AA genotype was lesser than with GG genotype (39.35 and 43.67 kg, p = 0.02, respectively). The days open is numerically better in AA genotype animals (99.35 days), but the difference between the three genotypes was non‐significant. The distinct significant associations reported in this study suggested that Leptin is reputable candidate genetic marker, which might be used to enhance animals’ genetic potential for milk production in conjunction with reproduction.  相似文献   
3.
Atlantic salmon ( Salmo salar L.) fry were reared on a fishmeal-based diet with three different levels of vitamin D3 (0.2, 5 and 57 mg vitamin D3 kg–1 feed, ww) from first-feeding for 14 weeks. No significant differences were recorded in weight, length, specific growth rate, mortality, or kidney calcium concentration between the different dietary groups. No skeletal malformations or histopathological changes were recorded in any of the dietary groups. These results suggest Atlantic salmon fry to be highly tolerant of megadoses of vitamin D3 over a limited period of time.  相似文献   
4.
纪念性景观是城市绿地的重要组成部分,其地被植物的配置具有明显的景观特色。通过对典型纪念性景观——南京市雨花台风景区的地被植物的种类、生活型分类、应用方式、平面布置形式及应用分类进行调查,并对其配置进行分析探讨,提出了加大对乡土和野生地被植物资源开发力度、科学引入外地优良的地被植物、增加地被植物的配置艺术性以及提高植被养护管理水平等建议。  相似文献   
5.
6.
The effects of salt stress on physiological factors, such as inorganic ion absorption and antioxidative enzyme activities, of rice ( Oryza sativa L. cv. Anapurna) and Echinochloa oryzicola Vasing were investigated. Although having similar morphology, rice and E. oryzicola possessed considerably different salt-tolerance mechanisms. Echinochloa oryzicola was more salt-tolerant than rice. When exposed to salt stress (100 mmol L−1 sodium chloride, NaCl; six days), E. oryzicola had the ability to limit the accumulation of sodium ions (Na+), maintained high potassium ion (K+) content and had a constantly higher K+/Na+ ratio than rice. Rice was not effective in limiting Na+ absorption but had a higher antioxidative capacity than E. oryzicola . The constitutive activities of superoxide dismutase (SOD) and catalase of rice were three and five times higher than that of E. oryzicola, respectively. Induced activities of SOD, ascorbate peroxidase and glutathione reductase were also higher in rice than in E. oryzicola . The high antioxidative capacity was one of the tolerance mechanisms used by rice to cope with salt stress. Therefore, the salt tolerant-mechanisms are different between the two plants.  相似文献   
7.
8.
9.
An efficient, copper-based catalyst has been discovered that oxidizes a wide range of alcohols into aldehydes and ketones under mild conditions. This catalytic system utilizes oxygen or air as the ultimate, stoichiometric oxidant, producing water as the only by-product.  相似文献   
10.
Summary. A method of exposing seedlings of Norway spruce (Picea abies (L.) Karst.) to 14CO2 is described. Within the 1st hr alter 14CO2 exposure, no translocation of the 14C out of the treated branch could be observed. After a 24-hr period, however, the 14C in dormant seedlings had been translocated basipetally to part of the root system only, with no lateral diffusion of the 14C-compounds in the stem. About a week after exposure, both symplastic and apoplastic patterns of translocation had caused a more uniform distribution of 14C. In seedlings at active internode elongation, the translocation patterns were fundamentally identical to those in dormant seedlings, but the active shoot growth had led to a more uniform distribution of the 14C.
Simazine at 20 ppm had apparently stimulated both the photofixation of 14CO2 and the rate of translocation of the 14C-assimilates. At 30 ppm, however, simazine had blocked the translocation of nutrients to the roots. On the other hand, the 14CO2 uptake was not influenced. The simazine incubation had apparently no influence on the synthesis of cationic photosynthate.  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