外源NO缓解果树胁迫的作用机理和研究进展

一氧化氮(Nitric oxide, NO)是一种重要的信号分子，广泛参与果树的生长发育调控和对生物与非生物环境胁迫的应答反应。大量证据表明，外源NO是缓解果树干旱、高温和酸雨等胁迫中重要的信使分子，其信号转导机制目前已广受人们关注。文章综述了NO的来源、NO的双重作用及作用机理、NO与其他信号分子间的关系以及近年来外源NO缓解果树胁迫的研究进展，为外源NO缓解果树胁迫的深入研究提供参考资料。     

高产型徐香猕猴桃树体结构及土壤养分状况分析

为明确猕猴桃果园的生产潜力，在普查的基础上对两个管理水平较高的徐香猕猴桃果园的树体结构及土壤养分状况进行分析。结果表明，高产型徐香猕猴桃树体的合理结构为成龄树冬季修剪后单株保留17个左右结果母枝，每枝保留15~21个有效芽，折合每667 m留长枝量为1 496个，留芽量为22 440~23 760个，7月份叶果比为3.33∶1。土壤速效氮为16.5 mg/kg，速效磷64.8 mg/kg，速效钾209.6 mg/kg，速效镁和速效铁分别156.6 mg/kg和3.58 mg/kg，有机质含量1.13%。可见，充足的肥料投入、枝芽数量及合理的叶果比是高产稳产的基本保证。     

番石榴番花生产应用研究

该文论述在广西职业技术学院番石榴试验园进行促夏梢、番花，成功利用番花生产番花果的试验方法、措施、关键技术等，并对番花果果实的营养成分进行测定，分析其与正造果之间的差异。试验表明番花果生产的关键技术主要有三：一是抓住时机、科学修剪和用好促发夏梢、番花肥。二是合理留好正造果；三是做好番花果保花保果、水肥管理及果实套袋等。     

气相色谱法测定水果中咪鲜胺残留量的方法研究

采用丙酮震荡提取样品，在水解衍生的步骤中创造性地使用试管加入吡啶盐酸盐，于220℃的烘箱里水解1.5 h，经过处理后使用气相色谱ECD进行测定。结果表明：该方法的线性范围为0.005～0.500 ng，相关系数为0.999 9；对香蕉、绿橙、花牛苹果、青苹果、猕猴桃、砀山梨6种空白基质分别进行了0.01、0.10、1.00 mg/kg 3个水平加标，其回收率为81.0%～106.4%，相对标准偏差(RSD，n＝5)为0.3%～5.7%；该方法的最低检出限为0.01 mg/kg，并且烘箱水解的新方法操作简便     

果蜡处理对低温贮藏下采后菠萝果实激素的影响

以菠萝品种‘巴厘’的果实为试材，研究果蜡处理对低温贮藏下采后菠萝激素的影响，结果表明：果蜡处理降低了冷藏菠萝果实脱落酸(ABA)、赤霉素(GA)和玉米素(ZR)含量，增加了吲哚乙酸(IAA)含量，并且ABA 和GA含量均与冷害指数极显著相关(P＜0.01)，相关系数分别是0.879和0.909。表明低温胁迫下采后菠萝的ABA和GA与抗冷性密切相关，果蜡处理降低了ABA和GA含量，从而提高菠萝抗冷性。     

Postponed germination of Puccinia recondita urediospores deposited on wheat seedlings. II. Infectivity of urediospores after postponed germination

Urediospores ofPuccinia recondita f.sp.tritici were applied to wheat seedlings. Inoculated plants were placed in a growth chamber to expose the spores to dry periods from zero to nine days at near-optimal temperatures (ca 18 °C). The dry period was followed by a wet period varying from 2 to 24 hours for germination of spores and infection of plants. Infection results were subjected to analysis of variance. The main effects dry period, wet period, and temperature were highly significant. The dry period×wet period interaction was significant. The interaction implied that the effects of post-detachment, ripening of germinable spores appeared in their resulting infectivity. There were two forms of post-detachment ripening, a slow ripening during the dry period and a faster ripening during the wet period. The two forms of ripening showed a non-additive compensatory interaction. The effect of post-detachment ripening on infectivity of germinated spores was more pronounced at 15 than, at 18 or 20 °C; the effect was strongest during the first day of the dry period. At dry periods of over 6 days, infectivity of germinated spores decreased, especially at the higher temperatures. Prolonged exposure, of spores to a dry period apparently damages the spores even though they are still able to germinate.Samenvatting Uredosporen van de bruine roest van tarwe (Puccinia recondita f.sp.tritici) werden over het eerste blad van tarwekiemplanten verstoven. De aldus geïnoculeerde planten werden in een klimaatkamer geplaatst bij ca. 18 °C om de sporen bloot te stellen aan droge perioden van 0 tot 9 dagen. De droge perioden werden gevolgd door natte perioden van 2 tot 24 uur om de sporen te laten kiemen en de planten te infecteren. Na de natte periode werden de planten bij verschillende temperature geplaatst om de latente periode en de vorming van sporenhoopjes te bepalen. De hoofdeffecten op de vorming van sporenhoopjes waren zeer significant: duur van de droge periode, duur van de natte periode en temperatuur. Twee vormen van sporenrijping werden gevonden bij rijping vnn sporen, die los op het blad lagen (rijping, buiten de sporenhoopjes), een langzame rijping tijdens de droge periode en een snelle rijping tijdens de natte periode. Deze twee vormen van rijping vertoonden statistische interactie met enige wederzijdse compensatie. Het effect van deze sporenrijping (buiten de sporenhoopjes) op de infectiviteit van gekiemde sporen was bij 15 °C duidelijker dan bij 18 en 20 °C; het effect was het sterkst tijdens de eerste dag van de droge periode. Bij droge periodes langer dan 6 dagen daalde de infectiviteit, vooral bij de hogere temperaturen.     

Epidemiology and control of Menangle virus in pigs

OBJECTIVE: To describe the epidemiology and eradication of Menangle virus infection in pigs. DESIGN: Field observations and interventions, structured and unstructured serological surveys, prospective and cross-sectional serological studies and laboratory investigations. PROCEDURE: Serum samples were collected from pigs at a 2600-sow intensive piggery in New South Wales that experienced an outbreak of reproductive disease in 1997. Serum samples were also collected from piggeries that received pigs from or supplied pigs to the affected piggery and from other piggeries in Australia. Serum and tissue samples were collected from pigs at piggeries experiencing reproductive disease in New South Wales. Sera and faeces were collected from grey-headed flying foxes (Pteropus poliocephalus) in the region of the affected piggery. Serum samples were tested for neutralising antibodies against Menangle virus. Virus isolation was attempted from faeces. RESULTS: Following the outbreak of reproductive disease, sera from 96% of adult pigs at the affected piggery, including sows that produced affected litters, contained neutralising antibodies against Menangle virus. Neutralising antibodies were also detected in sera from 88% of finisher pigs at two piggeries receiving weaned pigs from the affected piggery. No evidence of Menangle virus infection was found in other piggeries in Australia. In cross-sectional studies at the affected piggery, colostral antibodies were undetectable in most pigs by 14 to 15 weeks of age. By slaughter age or entry to the breeding herd, 95% of pigs developed high antibody titres (> or = 128) against Menangle virus in the virus neutralisation test. Menangle virus was eradicated from the affected piggery following a program of serological testing and segregation. Neutralising antibodies against Menangle virus were also detected in P poliocephalus from two colonies in the vicinity of the affected piggery. Two piggery workers were infected with Menangle virus. There was no evidence of infection in cattle, sheep, birds, rodents, feral cats and a dog at the affected piggery. CONCLUSIONS: Serological evidence of infection with Menangle virus was detected in pigs at a piggery that had experienced reproductive disease, in pigs at two associated piggeries and in fruit bats in the region of the piggery. Two humans were infected. The mode of transmission between pigs is unknown, but spread by faecal or urinary excretion is postulated. This virus can be eradicated by the segregation of pigs into discrete age groups.     

基于分子遗传标记技术的实蝇种群遗传关系研究进展

分子遗传标记技术已用于分析实蝇的种群遗传关系,本文介绍了分子遗传标记技术在实蝇的起源、入侵、定殖、扩散及其他方面的研究进展,首次分析了我国实蝇种群遗传研究的现存问题并针对检疫性实蝇种群遗传关系研究提出了建议.     

Testing variability in pathogenicity ofPhytophthora cactorum, P. citrophthora andP. syringae to apple, pear, peach, cherry and plum rootstocks

The relative virulence ofPhytophthora cactorum andP. syringae originating from almond trees, and ofP. citrophthora originating from citrus, to apple, pear, peach, cherry and plum rootstocks, was studiedin vivo andin vitro. Results of the different experiments were in good agreement. All testedPhytophthora isolates showed little virulence to pear rootstocks-causing only minor crown rot symptoms - and no virulence at all to apple rootstocks. In contrast, they were highly virulent to stone fruit rootstocks, causing crown rot disease. The non-pathogenicity of these isolates to pome rootstocks could be interpreted as strict host specificity.