宁夏枸杞雄性不育育性标准研究(英文)     

曹君迈  任贤  刘建利  贝盏临  宋莎 《（《农业科学与技术》）编辑部》2009,(3)

Botanical features of "YX-1" reproductive organ and bearing rate by number of pollen granules in pollen sacs of Lycium chinensis was observed and researched through field investigation, smear preparation and paraffin sections. YX-1 of Lycium chinensis was determined as incomplete male sterility and further classified into complete sterile type, sterile type I and sterile type II. The fertility standard of male sterility of Lycium chinensis was preliminarily proposed to establish a basis for crossbreeding of male sterility of Lycium chinensis.  相似文献   

基于RAGA的投影寻踪模型在土壤重金属污染评价中的应用   总被引：2，自引：0，他引：2  

刘慧卿张先起  杨会娟 《河南农业科学》2005,(10):60-63

将投影寻踪分类模型(PPC)应用于土壤环境质量综合评价中,利用基于实码的加速遗传算法(RAGA)来优化投影方向,将多维数据指标转换成低维子空间,通过寻求最优投影方向来计算投影函数值,从而根据投影值的大小进行土壤综合评价。并结合实例进行了应用,其结果合理,避免了权重确定的人为干扰,为土壤环境质量评价提供了一条新的方法和思路。  相似文献   

Seasonality of oocyte development and pigmentation in Atlantic salmon, Salmo salar     

B. North  M. Porter  V. Crampton  D. Guerrero-Tortolero  N. Bromage 《Fish physiology and biochemistry》2003,28(1-4):513-514

This study identifies the presence of a spring drop of flesh pigmentation that coincided with oocyte atresia in Atlantic salmon and outlines the potential influence that additional lighting and feed management strategies can have on these processes.  相似文献   

Clinical response of masitinib mesylate in the treatment of canine macroscopic mast cell tumours          下载免费PDF全文

J. Grant  S. North  D. Lanore 《The Journal of small animal practice》2016,57(6):283-290

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Fin erosion on rainbow trout on commercial trout farms in the United Kingdom     

St-Hilaire S  Ellis T  Cooke A  North BP  Turnbull JF  Knowles T  Kestin S 《The Veterinary record》2006,159(14):446-450

Fish weighing less than 30 g and more than 100 g were sampled from 38 rearing units on 10 commercial farms growing rainbow trout for the table market. A fin index was calculated for each of the eight rayed fins on 949 trout by dividing their length by the standard length of the fish. There was a large range in the indices of all eight fins. The fin indices of the small and large fish were compared, controlling for farm effect. With the exception of the dorsal fin, all the indices were larger for the small fish than for the large fish, but the magnitude of the difference was greater for some fins than others. In comparison with the fins of wild fish, the pectoral and dorsal fins appeared to be most eroded and the damage to these fins was evident even in the small fish. The erosion of the caudal, anal and ventral (or pelvic) fins was more prominent in the larger fish. Variations in the fin indices of the caudal, anal and ventral fins suggested that there was little variation between rearing units on the same farm, but that there was significant variation between individual fish in the same rearing units, and between fish on different farms.  相似文献   

Biological Features of Flowering and Development of Male Gametophyte in Anthurium andreanum     

Bai Jing-shu Zhu Xiao-qing Li Feng-lan Guo Hui-hong Li Zhi-dan College of Biological Sciences  Biotechnology  Beijing Forestry University  Beijing  P. R. China North National Forest Plantlet Exemplary Base  Beijing  P. R. China 《中国林学(英文版)》2005,7(1)

The aim of this study is to follow each development stage of inflorescence in order to understand the biological feature of flowering and the development of male gametophyte in Anthurium andreanum “Arizona" and to try to find the optimum conditions for its pollination. The methods of dissection and paraffin section were adopted to examine the structural characteristics of anthurium’s tiny floret and the development of the microspore. All the florets of the anthurium arrange on the rhachis helically sub- tended by a colorful bract. Each tiny floret has one gynoecium, four tepals and four stamina. The bract and the florets show different colors during the whole blooming period. The ovary is bicarpellary and has two locules, each of which has one anatropous ovule. The placenta is of a central placentation type. The stylar canal cells not only can produce the secretory mucilage but also can release their own cytoplasm caused by their self-disintegration before the pistil reaches its maturity. The wall of the anther is composed of four layers: epidermis, endothecium, middle layer and tapetum. The tapetal cells and the middle layers’ cells degenerated completely dur- ing meiosis of microsporocytes. The pollen grains were 2-celled at the time of anther dehiscence. Early morning, when the inflores- cences stay at their fifth development stage, is the optimum opportunity for pistil to get pollen grains. The pollen-collection should be done at the end of the seventh stage.  相似文献   

Variability in mixing efficiency and laboratory analyses of a common diet mixed at 25 experiment stations     

Cromwell GL  Brendemuhl JH  Chiba LI  Cline TR  Crenshaw TD  Dove CR  Easter RA  Ewan RC  Ferrell KC  Hamilton CR  Hill GM  Hitchcock JD  Knabe DA  Kornegay ET  Lewis AJ  Libal GW  Lindemann MD  Mahan DC  Maxwell CV  McConnell JC  Nelssen JL  Pettigrew JE  Southern LL  Veum TL  Yen JT;North Central Region Committee on Swine Nutrition 《Journal of animal science》2003,81(2):484-491

An experiment involving 25 experiment stations in the North Central and Southern regions (NCR-42 and S-288, respectively) was conducted to assess the degree of uniformity of diet mixing among stations and to assess the variability among station laboratories in chemical analysis of mixed diets. A fortified corn-soybean meal diet was mixed at each station using a common diet formula (except for vitamin and trace-mineral additions). The diet was calculated to contain 14% crude protein (CP), 0.65% Ca, 0.50% P, and 125 ppm Zn (based on 100 ppm added Zn). After mixing, samples were collected from the initial 5% of feed discharged from the mixer, after 25, 50, and 75% was discharged, and from the final 5% of discharged feed. The five samples were sent to the University of Kentucky, finely ground, and divided into subsamples. Each set of five subsamples from each station was distributed to three randomly selected stations for analysis of CP, Ca, P, and Zn (i.e., each station analyzed five diet sub-samples from three other stations). In addition, two commercial and two station laboratories analyzed composites of the five subsamples from each of the 25 mixed diets. Based on the laboratories that analyzed all diets, means were 13.5, 0.65, and 0.52%, and 115 ppm for CP, Ca, P, and Zn, respectively. Ranges of 11.8 to 14.6% CP, 0.52 to 0.85% Ca, 0.47 to 0.58% P, and 71 to 182 ppm of Zn were found among the 25 diet mixes. The coefficients of variation among the 25 diet samples for CP, Ca, P, and Zn were 4.3, 9.3, 4.1, and 17.4%, and among the 25 laboratories were 3.6, 12.5, 10.7, and 11.1%, respectively. Overall analyses of the five sub samples were, respectively, CP: 13.4, 13.6, 13.4, 13.5, and 13.4% (P < 0.06); Ca: 0.66, 0.67, 0.67, 0.66, and 0.67%; P: 0.50,0.51,0.51,0.50, and 0.50%; and Zn: 115, 116, 112, 113, and 120 ppm (P < 0.001). Diets were not uniformly mixed at all stations (station x sample No. was P < 0.08 for Ca and P < 0.01 for CP, P, and Zn). Among stations, the range of the five samples, expressed as a percentage of the mean and averaged for CP, Ca, P, and Zn, varied from +/- 1.1% (i.e., 98.9 to 101.0%) to +/- 12.9% (84.6 to 110.4%), with an overall average of +/- 5.2%. Neither type nor volume of mixers was related to mixing uniformity. The results suggest that uniformity of diet mixes varies among experiment stations, that some stations miss their targeted levels of nutrients (especially Zn), and that the variability among experiment station laboratories in analysis of dietary Ca, P, and Zn in mixed diets is quite large.  相似文献   

Library     

Veterinary Clinics of North America  Equine Practice: Wound Management 《Journal of Equine Veterinary Science》2005,25(6):260-261

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Future of the RCVS library     

North D 《The Veterinary record》2002,150(14):455-456

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Spatial variability in microclimate in a mixed-conifer forest before and after thinning and burning treatments   总被引：1，自引：0，他引：1  

Siyan Ma  Amy Concilio  Brian Oakley  Malcolm North  Jiquan Chen 《Forest Ecology and Management》2010

In the western United States, mechanical thinning and prescribed fire are common forest management practices aimed at reducing potential wildfire severity and restoring historic forest structure, yet their effects on forest microclimate conditions are not well understood. We collected microclimate data between 1998 and 2003 in a mixed-conifer forest in California's Sierra Nevada. Air and soil temperatures, relative humidity, photosynthetically active radiation (PAR), wind speed, soil heat flux, and soil volumetric moisture were measured at the center of 18 four-ha plots. Each plot was assigned one of six combinations of thinning and burning treatments, and each treatment was thus given three replications. We found that spatial variability in microclimate, quantified as standard deviations among monthly values of each microclimatic variable across different locations (n ≤ 18), was significantly high and was influenced primarily by elevation and canopy cover. The combination of thinning and burning treatments increased air temperature from 58.1% to 123.6%. Soil temperatures increased in all thinned plots. Air moisture variables indicated that treatments made air drier, but soil moisture increased in the range 7.9–39.8%, regardless of treatment type. PAR increased in the range 50.4–254.8%, depending on treatment type. Treatments combining thinning and burning increased wind speed by 15.3–194.3%. Although soil heat flux increased dramatically in magnitude in some plots, overall treatment effects on G were not statistically significant. We discussed the significance and implications of the spatial variability of microclimate and the treatment effects to various ecological processes and to forest management.  相似文献