国外松芽流脂病发生与防治

近年来,浙江省局部地区国外松纯林受芽流脂病危害较为严重.通过定点现察、分离培养、光镜检查、电镜现察、微量元素测定和用硼砂防治罹病松树等方法,基本查清国外松芽流脂病在浙江省的发生情况,明确了国外松芽流脂病的3种症状顶芽枯死型、丛枝型和枯梢型.国外松芽流脂病是由于松树自身和土壤中的微量元素--有效硼含量不足引起的生理性病害.用喷洒3.0g@kg-1或5.0g@kg-1硼砂溶液防治该病效果显著,防治区病情指数与对照相比平均下降38.5,松树的年平均高生长量也比对照大14.8cm.表4参4     

图书馆工作人员应该转变的六个观念

文章认为，要使图书馆工作适应新的技术革命和社会主义市场经济的需要，就必须转变观念。当前需要转变的观念有以下六个方面:图书馆由藏书中心变成文献资料中心、信息中心、智力开发中心;从关门办馆到开门办馆:从无偿服务到有偿服务:从独自办馆到馆际协作:从手工操作到运用现代技术手段:从与世无争到积极竞争。     

近冰点温度贮藏草莓的研究

草莓呼吸旺盛,果皮薄易受伤,难以贮藏。利用近冰点温度贮藏可以明显地抑制草莓的呼吸作用,结合小袋包装的气密性,改善了包装内部的气体组成,提高草莓果实周围的相对湿度并减少空气对流,从而抑制了草莓在贮藏过程中糖分、水分的损耗,减少了糖酸比值的下降。保持了一定的感观指标,可使草莓的贮藏时间延长。     

靠接换砧矫治枳砧甜橙缺铁黄化研究

靠接红桔、酸桔和枸头橙砧,矫治枳砧甜橙缺铁黄化有明显效果。其中,以枸头橙效果最好,以下依次为酸桔和红桔,靠接砧苗后树势逐年恢复,产量成倍增加,靠接红桔、酸桔和枸头橙分别比对照增产3.3、1.4和1.5倍;对提高果实含糖量、果汁率和降低含酸量亦有良好效果。     

Porcine reproductive and respiratory syndrome virus: morphological, biochemical and serological characteristics of Quebec isolates associated with acute and chronic outbreaks of porcine reproductive and respiratory syndrome.

Cytolytic and noncytolytic strains of the porcine reproductive and respiratory syndrome virus (PRRSV) were isolated in primary cultures of porcine alveolar macrophages (PAM) from lung homogenates of stillborn fetuses or blood samples of dyspneic piglets collected from Quebec pig farms having experienced acute or chronic outbreaks of PRRS. Serological identification of the virus was confirmed by indirect immunofluorescence and indirect protein A-gold immunoelectron microscopy using reference antiserum prepared from experimentally-infected specific pathogen free (SPF) piglets and monoclonal antibodies (MoAbs) directed against the p15 nucleocapsid (N) protein of the reference ATCC-VR2332 isolate. Intracytoplasmic enveloped viral particles that tended to accumulate into cytoplasmic vesicles were observed in the infected PAM; no budding was demonstrated at the level of the cytoplasmic membrane. The extracellular virions appeared as pleomorphic but mostly spherical enveloped particles, 50-72 nm in diameter (averaged diameter of 50 particles was 58.3 nm), with an isometric core about 25-30 nm. Buoyant density of the virus in CsCL density gradients was estimated to 1.18-1.20 g/mL. No hemagglutinating activity was demonstrated. Analysis of semipurified virions of isolate IAF-exp91 by radioimmunoprecipitation (RIPA) and Western immunoblotting experiments, using reference rabbit and porcine hyperimmune sera, revealed four major viral proteins, a predominant 15 kD N protein and three other proteins with predicted M(r_ of 19, 26 and 42 kD. Progeny viral particles produced in PRRSV-infected PAM in the presence of tunicamycin lacked the 42 kD protein, thus confirming its N-glycosylated nature. Immunoprecipitation experiments using the anti-ATCC-VR2332 MoAbs confirmed the close antigenic relationships between Quebec and American reference isolates of PRRSV.     

PEG诱导水分胁迫对柑桔幼苗细胞质膜透性及脯氨酸含量的影响

柑桔叶片相对含水量(RWC)随聚乙二醇(PEG)处理渗透势的降低而依次降低;叶片细胞质膜透性随PEG处理浓度的增加而依次增大;幼苗叶片累积脯氨酸的数量随水分胁迫时间和强度递增。     

如东县鸡腿病病因的调查研究

本文对如东县４０个养鸡户的鸡腿病进行了门诊与跟踪调查。从传染病、营养代谢病及饲养管理三个方面对发病原因进行了初步的探讨。结果表明：营养缺乏和代谢紊乱（特别是钙、磷）是该县鸡腿病的主要原因，传染性腿病如疑似病毒性关节炎、禽脑脊髓炎、葡萄球菌性关节炎等也不容忽视。     

两种一年生植物在替代试验中的相互竞争关系

（1）用替代试验研究了燕麦（Aneva sativa）和箭舌豌豆（Vicia sativa）在混播中的竞争相互作用。为了攻混播比例对两种植物在混播条件下的行为影响，田间试验设为5个混播总密度和5种混播比例，共了5次。（2）方差分析表明，相对总生物量（RYT）和竞争平衡指数（CBI）对总密度，混播比例和生长时间的反应敏感。总密度对RYT和CBI的影响高度显著，在大多数情况下，混播比例对RYT和CBI的影响不显著。（3）本文研究的结果表明，持续时间对RYT和CBI很强的影响，在第1次测定时，RYT值接近1而BI值接近0，这一事实表明，种间无竞争或互惠作用。而在生长旺盛期，种间竞争较为剧烈。（4）本研究结果表明，箭舌豌豆的生长严惩受到燕麦的抑制作用，这说明箭舌豌豆在与燕麦混播时表现为竞争上的弱者。