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31.
David M. Spooner Andrés Contreras M. John B. Bamberg 《American Journal of Potato Research》1991,68(10):681-690
A joint Chilean, United States potato (Solanum sect.Petota) germplasm collecting expedition was conducted in Chile between January 21–March 30, 1989. The trip resulted in collections ofSolanum brevidens (50 accessions),S. etuberosum (28 accessions),S. maglia (3 accessions) and indigenous primitive landraces ofS. tuberosum (24 accessions). Comments are presented on the habitats, distribution, and potential and realized breeding value of these species. 相似文献
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China is the world’s leading producer of potatoes, growing 22% of all potatoes. Production continues to rise, owing to increases
in both land devoted to potato production and yield per hectare. Most potato production occurs in the northern and southwest
regions of the country. The processing of coarse starch is the most important component of the potato processing industry
in China, but other processing industries, such as crisps and French fries, are expanding. Major production constraints include
inadequate germplasm resources for cultivar development, the lack of high quality seed potatoes, and limited access to equipment
for mechanized cultivation, planting, fertilizing, spraying, and harvesting. Additional weaknesses in storage and transportation
technologies must be addressed, as they are the major constraints for the healthy development of the potato industry. The
introduction and improvement of these technologies will ensure the sustainable development of the potato industry in China. 相似文献
34.
为探究人工施用竹炭对卷心菜叶绿素含量和荧光参数的影响,进而明确卷心菜的最适竹炭有机肥施用量,在田间试验条件下设置了无碳(CK)、中碳(MC)和高碳(SC)3个处理,对卷心菜莲座期和结球期的叶绿素含量及荧光参数进行测量研究.结果表明:(1)结球期的卷心菜叶绿素含量极显著高于莲座期(p0.01),且随着竹炭量的增加,两个时期的叶绿素含量变化趋势一致,从高到低依次为:MC,CK,SC.(2)结球期的卷心菜初始最小荧光Fo、初始最大荧光Fm、PSⅡ的最大光化学效率Fv/Fm,PSⅡ的潜在活性Fv/Fo、非光化学猝灭系数qN均低于莲座期,而PSⅡ实际光化学效率ΦPSⅡ、光化学猝灭系数qP高于莲座期,且随着竹炭量的增加,两个时期的这些参数均表现出一致的变化趋势,Fo和qN均呈"V"型变化,而Fm,Fv/Fm,Fv/Fo,ΦPSⅡ和qP均呈现倒"V"趋势,但对ΦPSⅡ和qP没有显著影响(p0.05).说明结球期的卷心菜光合作用高于莲座期;当竹炭量由CK增加到MC,有利于提高叶片叶绿素含量,增强光能利用率,减少植株热耗散,提高植株光合作用;但随着竹炭量进一步增加到SC,卷心菜叶片叶绿素含量降低,光能利用率减弱,热耗散增加,光合作用受到抑制,即中炭(MC)处理条件下,此卷心菜长势最优,表明中炭是该卷心菜生长的最适竹炭有机肥施用量. 相似文献
35.
Complement fixing antibodies were measured in sera from animals immunised with either Theileria annulata sporozoites or autologous or allogeneic schizont-infected mononuclear cells using a complement-mediated micro-cytotoxicity test. The test demonstrated the presence of anti-lymphocyte antibodies in allogeneic cell-immunised animals, which were not detectable in autologous cell- or sporozoite-immunised animals; also that these antibodies were directed to T. annulata-infected and (MHC) class I antigens. Their potential importance in repeated immunisations is discussed. 相似文献
36.
H T Koch J G Ocama F C Munatswa B Byrom R A Norval P R Spooner P A Conrad A D Irvin 《Veterinary parasitology》1988,28(1-2):19-32
Theilerial parasites of cattle were isolated by a variety of methods from the Harare area of Zimbabwe. Parasite stocks were established in lymphoid cell cultures and as cryopreserved sporozoite stabilates in the laboratory. Fourteen stocks in culture were characterized by testing them with monoclonal antibodies (MAb) raised against T. parva parva and T. parva lawrencei antigen. Two of these stocks had profiles similar to T. taurotragi isolates from East Africa, the other stocks had profiles similar to T. parva parva, however, many of them failed to bind MAb No. 7, and this may be a distinctive feature for T. parva bovis. Three T. p. bovis stocks were titrated by injecting different doses of the respective stabilates into pairs of cattle. Reactions ranged from severe to inapparent according to the stocks and dose used, but no fatal reactions were recorded, even at the highest dose rate. On recovery, all cattle were given homologous and then heterologous challenge. The results of the latter challenge showed that the Boleni stock gave good cross-protection against challenge with two other Zimbabwean stocks. This stock may therefore be a candidate for immunizing cattle, under field conditions, to protect them against T. p. bovis in Zimbabwe. Non-pathogenic strains of T. p. bovis may be difficult to distinguish from T. taurotragi unless cross-challenge experiments can be conducted and/or MAb profiles have been made. An improved serological test is needed to differentiate antibodies to these parasites in the sera of recovered cattle. 相似文献
37.
Infection of bovine monocyte/macrophage populations with Theileria annulata and Theileria parva 总被引:3,自引:0,他引:3
E J Glass E A Innes R L Spooner C G Brown 《Veterinary immunology and immunopathology》1989,22(4):355-368
Infection and transformation of cells of the bovine immune system by Theileria annulata and T. parva were compared. Preliminary experiments with mammary gland macrophages indicated that they were permissive to infection by T. annulata but only to a limited extent by T. parva. Further experiments involved several purified subpopulations of bovine cells including bovine monocytes, T cells and MHC class II positive and negative populations. These subpopulations were incubated with T. annulata or T. parva sporozoites in limiting dilution cultures. T. annulata preferentially infected macrophage type cells and also MHC class II positive cells, whereas the frequency of MHC class II negative cells infected by this parasite was negligible. T cells also showed a very low level of infection. In complete contrast, T. parva preferentially infected T cells and did not infect cells phenotypically defined as monocytes at all. These results suggested that class II expression was necessary for T. annulata infection and not necessary for, though not a barrier to T. parva infection. T. annulata infected cell lines all expressed class II molecules to varying degrees. Other available phenotypic markers were only expressed at very low levels or no longer expressed. The immunological significance of the different cell preferences and phenotypes of infected cell lines of T. annulata and T. parva is discussed. 相似文献
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