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71.
抱子甘蓝花培苗倍性的快速鉴定 总被引：13，自引：0，他引：13
采用花药培养获得加倍单倍体 (DH)是甘蓝类蔬菜自交不亲和系选育的主要方法之一 .然而 ,花药培养后代是倍性水平不同的混合群体 ,及早鉴定出真正的 DH具有重要的意义 .本文阐述 DNA流式细胞仪测定法和形态学鉴定法在花培苗倍性鉴定上的应用 ,并以抱子甘蓝的花培苗群体为材料 ,采用这两种方法鉴定其倍性组成 .结果表明 ,DNA流式细胞仪测定法可以鉴别群体的各种倍性水平 ,而形态学鉴别法可以把群体中的二倍体与单倍体、四倍体及其它倍体分开 .若以 DNA流式细胞仪测定法的鉴定结果为标准 ,苗期形态学鉴定的准确率可达 94.2 % .与 DNA流式细胞仪测定法相比 ,形态学鉴定方法具有更快速、简便和实用性强等特点 相似文献
72.
A "Schrodinger Cat" Superposition State of an Atom 总被引：1，自引：0，他引：1
A "Schrodinger cat"-like state of matter was generated at the single atom level. A trapped 9Be+ ion was laser-cooled to the zero-point energy and then prepared in a superposition of spatially separated coherent harmonic oscillator states. This state was created by application of a sequence of laser pulses, which entangles internal (electronic) and external (motional) states of the ion. The Schrodinger cat superposition was verified by detection of the quantum mechanical interference between the localized wave packets. This mesoscopic system may provide insight into the fuzzy boundary between the classical and quantum worlds by allowing controlled studies of quantum measurement and quantum decoherence. 相似文献
73.
In 2012 when many sheep flocks in northern‐central Tasmania were experiencing a high prevalence of ovine Johne's disease, 34 wild adult fallow deer shot on or near infected properties were negative to microscopic Mptb lesions of the ileo‐caecal valve, terminal ileum and ileo‐caecal lymph nodes. This study demonstrated 95% confidence of detecting Johne's disease in this fallow deer population if ≥10% of animals were shedding Mycobacterium avium subsp. paratuberculosis in their faeces, or if ≥21% of animals were sub‐clinically infected. 相似文献
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Hydatid disease in beef cattle has been reported to be widespread throughout Australia, but cattle bred and raised in the Northern Territory were previously believed to be free of the disease. Between 2010 and 2016, 1061 cattle from the Northern Territory were slaughtered at a New South Wales abattoir and inspected for hydatid disease. The proportion of cattle reported infected with hydatid disease was 3.5%. Individual cattle identification numbers indicated that the cattle included in the study had most likely remained within the Northern Territory from birth until immediately prior to slaughter, so were assumed to have become infected within the region. We suspect that the sylvatic cycle of Echinococcus granulosus transmission could be responsible for infection of cattle in this region. 相似文献
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77.
Resistance of Fasciola hepatica to triclabendazole 总被引：1，自引：0，他引：1
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SUMMARY The extent and causes of sheep losses in the semi-arid Mallee region of north-western Victoria were assessed by interviewing the owners of 79 randomly selected farms running 241 flocks in 1987/88 and 245 flocks in 1988/89. Mean annual losses were higher in ram flocks (21%) than in ewe flocks (7%), in flocks of non-Merino sheep (rams 24%, ewes 11%, weaners 5%) than in Merino (rams 11%, ewes 6%, wethers 4%, weaners 4%) and in ewe flocks 3 or more years old (10%) than in young ewe flocks (3.5%). In flocks where losses exceeded 5%, the causes most often reported by farmers were blowfly strike (especially in Merino sheep and weaners), ewe losses in autumn close to lambing, and heliotrope (Heliotropium europaeum) poisoning. Heliotrope poisoning was considered by the authors to be the main reason for the higher losses in old ewes than in young ewes and in non-Merino sheep than in Merino sheep. Losses of ewes associated with pregnancy and lambing were considered by the authors to be often predisposed by liver damage caused by heliotrope poisoning, and high losses in non-Merino ram flocks were attributed to both heliotrope poisoning and their ability to escape through boundary fences. Reasons for continuing high losses due to enterotoxaemia are discussed. Losses due to gastro-intestinal parasites, footrot and foot abscess were low. 相似文献
80.