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51.
巨桉纸浆原料林土壤养分与林木生长研究   总被引:5,自引:0,他引:5  
通过相关分析及回归分析,探讨了巨桉人工林土壤养分与林木生长的关系,结果表明:土壤速效N、速效P、土壤有机质的浓度与林木胸径、树高、材积极显著正相关,土壤全N、全P与林木胸径树高、材积显著正相关。建立了胸径、树高、材积与土壤养分的线形回归方程,最佳数学表达式说明速效N、速效P是影响巨桉林生长的关键土壤养分。  相似文献   
52.
甜菜不同种植方式的研究   总被引:2,自引:1,他引:1  
通过试验明确了覆膜移栽纸筒苗栽培方法具有覆盖地膜和育苗移栽双重效应,促进甜菜早发棵,早封垄。提早进入叶丛快速生长期和块根糖分积累期;改善了甜菜光合性能,增加了光合势、净光合率和光合产物经济系数,比不覆膜移栽纸筒苗的增产31%,产糖量增加27.12%,投入产出比大幅度增加。  相似文献   
53.
裴瑊 《青海农林科技》2005,(1):72-72,71
针对近年来甜糯等鲜食玉米在我市种植面积迅速扩大的现状,本文根据田间试验点总结出鲜食玉米超早熟设施栽培技术。旨在为广大农民实际生产应用提供参考依据。  相似文献   
54.
黄麻(新、引进)品种在闽南地区的产量(鉴定)试验   总被引:2,自引:0,他引:2  
洪建基  曾日秋 《中国麻业》2006,28(3):128-132
通过对中国农科院麻类所新选育的3个黄麻圆果种和12个国外引进的黄麻优异品种进行2002-2005年品种比较试验,结果表明:C90-2、C90-6、C89-6比对照种粤圆五号增产14.97%-19.34%,均达极显著水平。O-3、O-1、O-3(红茎)比对照种宽叶长果增产32.02%-34.21%,均达极显著水平。O-4(Ⅱ)比对照种增产12.28%达显著水平。C-1、C-5比对照种粤圆五号增产11.90%和7.82%。且主要经济性状优良,抗病力强。黄麻品种C90-2、C90-6、C89-6、O-3、O-1、O-3(红茎)、0-4(Ⅱ)、C-1和C-5适合于福建闽南麻区推广种植。  相似文献   
55.
56.
家蚕第2隐性赤蚁的遗传学研究——Ⅱ.ch-2基因的连锁分析   总被引:1,自引:1,他引:0  
Ch-2基因是继ch之后新发现的一种隐性赤蚁ch-2基因与pM(2)、Ze(3)、L(4)、Pe(5)、E~(EL)(6)、q(7)、st(8)、I(9)、w-2(10)、ms(12)、cf(13)、U(14)、Se(15)、cts(16)、B_m(17)、nb(19)、rb(21)、or(22)、sp(23)、Nd(25)、及Y_m等各标志基因都是独立遗传.Ch-2与mln杂交F_2代分离+ch-2+min:ch-2+min:ch-2mln:ch-2mln=523:284:231:0≈2:1:1:0;ch-2与elp杂交F_2代分离+ch-2+elf:ch-2+elp:+ch-2elp:ch-2elp=219:97:68:0≈2:1:1:0,充分说明ch-2与mln、elp是连锁遗传的,即ch-2基因位于第18连锁群.  相似文献   
57.
A total of 295 birds belonging to 19 species of 7 families of wild Passeriformes were examined by haemagglutination-inhibition test. The birds were caught for an international research program "Balt" at the time of autumn migration (August-September 1984). Their blood sera were examined for antibodies against 6 arbovirus antigens of the genera Alphavirus (Sindbis-SIN) and Flavivirus (tick-borne encephalitis-TBE, West Nile-WN) and family Bunyaviridae (Tahyna-TAH, Calovo-CVO and Bhanja-BHA). Antibodies against all studied viruses were detected at different frequencies: SIN 6.4%, TBE 7.1%, WN 9.7%, TAH 16.3%, CVO 12.1%, and BHA 1.0%.  相似文献   
58.
59.
Four infectious agents were isolated from the ticks Ixodes ricinus (L.) collected in the recreational area and park-forest of Prague. On the basis of cultivation, staining, biochemical, serologic properties, pathogenicity for animals and histological tests they were identified as Francisella tularensis with the following features: they are short, gram-negative rods of approximate dimensions of 0.3 X 0.8 micron, growing in enriched media after 3-4 day incubation at 37 degrees C. They form small circular, at first transparent, later greyish turbid colonies with regular rims. They are little active biochemically. They are susceptible to streptomycin and some broad spectrum antibiotics. They react positively with tularemic serum, but in lower titres than those in which this serum reacts with standard antigen. The microbes are highly pathogenic for mice, guinea-pigs, young rats, in which a massive bacteriemia occurs before death, but they do not kill rabbits. They multiply well in chick embryo, but do not grow in cell or tissue cultures. The most important histologic changes were observed in liver and spleen of mice. No pathologic changes were found in brain, lungs, heart, kidneys. Necroses were found in liver and in their marginal zones the microbes were present. Conspicuous were changes in numerous hepatocytes which became enlarged due to microbial multiplication and finally transformed into "sacs" packed with microbes. Histological and electronoptical examination showed that these are intracellular parasites fringed with a light lytic zone. Discussed is the problem to what extent the properties of the isolated strains are typical of F. tularensis as well as the importance of their detection from the aspect of epidemiology and differential diagnostics.  相似文献   
60.
A damaging virus isolated in the Netherlands from lettuce was studied and compared with a virus isolated from dandelion orginating from Czechoslovakia. It was found to biologically resemble dandelion yellow mosaic virus incompletely described from dandelion and lettuce in Great Britain (Kassanis, 1944, 1947) and from dandelion in Germany (Hein, 1963). Mechanical transmission was greatly improved by buffer solution and transmission byMyzus persicae seemed to be in the non-persistent manner. Longevity in vitro of the virus hardly exceeded one day. Thermal inactivation was between 60 and 65 °C and the dilution end-point was between 10 000 and 100 000. It was still infectious in leaf material dried and stored over CaCl2 at 4 °C for 6 1/2 years. The virus was isolated and purified with difficulty and was found to consist of one type of spherical particle of ca 30 nm diameter, with a sedimentation coefficient of 159 S, a buoyant density of 1.42 g.cm?3 and an A260/A280 ratio of 1.67. An antiserum was prepared with a titre of 256 in the agar double-diffusion test. The virus could be identified in crude extracts from lettuce andChenopodium amaranticolor by enzyme-linked immunosorbent assay (ELISA), but not by agar double diffusion. It could only be visualized in crude sap in the electron microscope after trapping of virus particles on antiserum-coated grids. The virus cannot yet be assigned to any known virus group. It is of potential economic importance to lettuce because of its occurrence in widely differing regions in Europe, its aggressiveness and virulence on 22 out of 23 lettuce cultivars tested (and on endive) and its pathogenicity toLactuca genotypes which are resistant to lettuce mosaic virus and other important pathogens of lettuce. ‘Laibacher Eis’ was the only cultivar showing some tolerance.  相似文献   
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