宁夏甜菜丛根病的研究

发生在宁夏甜菜上的一种病毒病的病株叶丛主要表现为黄化、焦桔和叶脉黄化坏死。从其分离的病毒粒子呈杆状,宽约20nm,长度为65—110nm、270—300nm和390—420nm,能侵染甜菜、菠菜、昆诺阿藜、苋色藜、番杏,与甜菜坏死黄脉病毒(BNYVV)抗血清呈阳性反应。综上所述,认为该病害是由BNYVV引起的。     

甜菜多粘菌基因组片段的克隆及PCR检测

根据资料报导设计引物,扩增Ｐｏｌｙｍｙｘａ　ｂｅｔａｅ的基因组片段,将其克隆在ｐＧＥＭ－３Ｚｆ（＋）质粒载体上,并通过双酶切、ＰＣＲ扩增和部分序列测定,证明克隆片段为Ｐ．ｂｅｔａｅ基因组片段。用扩增Ｐ．ｂｅｔａｅ基因组片段的引物对由Ｐ．ｇｒａｍｉｎｉｓ侵染小麦和Ｏ．ｂｒａｓｓｉｃａｅ侵染豇豆根系抽提的总ＤＮＡ进行ＰＣＲ扩增,均未获得任何ＤＮＡ产物,进一步证实了上述结果。对移入病土２、３．５天的甜菜苗单株根系进行ＤＮＡ粗提,移入病土３．５天的甜菜苗ＰＣＲ检测其已被Ｐ．ｂｅｔａｅ侵染,对确定Ｐ．ｂｅｔａｅ的早期侵染有重要意义。     

砂培体系中甜菜多粘菌生物学特性的研究

在改进的砂培体系中,甜菜多粘菌完成生活循环只需７天。利用砂培体系研究了多粘菌在不同ＰＨ值、光照,接种材料和接处量条件下,对寄主的侵染以及在其中繁殖的情况。 多粘菌完成侵染所需时间,侵染的游支孢子最初释放时间,游协孢子体外存活期和休眠孢子对温度的敏感性等生物学特性。     

甜菜多粘菌基因组片段的克隆4及PCR检测

根据资料报导设计引物，扩增Ｐｏｌｙｍｙｘａ ｂｅｔａｅ的基因组片段，钭其克隆在ＰＧＥＭ－３Ｚｆ（＋）质粒载体上，并通过双酶切、ＰＣＲ扩增和部分序列测定，证明克隆片段为Ｐ．ｂｅｔａｅ基因组片段。用扩增Ｐ．ｂｅｔａｅ基因组片段的引物 Ｐ．ｇｒａｍｉｎｉｓ侵染小麦和Ｏ．ｔｒａｓｓｉｃａｅ侵染豇豆根系抽提的总ＤＮＡ进行ＰＣＲ扩增，均未获得任何ＤＮＡ产物，进一步证实了上述结果。对移人病士２、３．５天的甜菜苗     

砂培体系中甜菜多粘菌生物学特性的研究

在改进的砂培体系中,甜菜多粘菌（Polymyxabetae）完成生活循环只需7天。利用砂培体系研究了多粘菌在不同pH值、光照、接种材料和接种量条件下,对寄主的侵染以及在其中繁殖的情况,研究了多粘菌完成侵染所需时间,侵染的游动孢子最初释放时间,游动孢子体外存活期和休眠孢子对温度的敏感性等生物学特性。     

甜菜坏死黄脉病毒分子生物学的研究进展

甜菜坏死黄脉病毒分子生物学的研究进展姚华建,于嘉林,刘仪（北京农业大学农业生物技术国家重点实验室,北京１０００９４）ＡｄｖａｎｃｅｓｏｆＲｅｓｅａｒｃｈｏｎＭｏｌｅｃｕｌａｒＢｉｏｌｏｇｙｏｆＢｅｅｔＮｅｃｒｏｔｉｃＹｅｌｌｏｗＶｅｉｎＶｉｒｕｓ￥Ｙ...     

甜菜坏死黄脉病毒外壳蛋白基因在甜菜转基因植株中的表达

甜菜坏死黄脉病毒(Beet Necrotic Yellow Vein Virus,BNYVV)是一种由甜菜多粘菌(Polymyxo be tae)传播的多分体植物病毒．基因组由4～5条单链正意RNA构成^[1]。60年代末,由Tamada首次报道^[2],这种病毒可对甜菜造成严重危害,侵染甜菜后产生丛根症状(Rhizomania),并导致甜菜产量和含糖 量的大幅度下降。除欧洲、北美及日本的严重发生以外,我国自70年代以来在东北、内蒙古及西北许多省区也有大量甜菜丛根病的发生报道^[3]。由于尚无有效药剂及措施用于甜菜丛根病或病毒传播介体的防治．在我国也无法采用大面积轮作作为防治手段,所以目前在世界各地及我国上述地区甜菜丛根病的发病面积逐年扩展,对甜菜生产和制糖业造成直接威胁。针对这一情况．本文报道了含有甜菜坏死黄脉病毒外壳蛋白基因的甜菜植株的转化再生工作,以期在甜菜亲本育种中获得新的抗性材料．为抗病毒品种的培育打下基础。     

甜菜坏死黄脉病毒外壳蛋白基因在大肠杆菌中的高效表达

将甜菜坏死黄脉病毒内蒙古分离物的外壳蛋白基因亚克隆到ｐＪＷ２上构建成在大肠杆菌中表达的载体。ＳＤＳ－ＰＡＧＥ及Ｗｅｓｔｅｒｎ ｂｌｏｔｔｉｎｇ检测的结果表明,该表达载体在大肠杆菌ＤＨ５α中经温度诱导后特异地表达２１ｋＤ的甜菜坏死黄脉病毒外壳蛋白。经光密度扫描估测,其表达量占大肠杆菌总蛋白的１９．５％。     

The evaluation of rhizomania resistant sugar beet for the UK

Sugar beet rhizomania disease, caused by Beet necrotic yellow vein virus and transmitted by the soil‐borne parasite Polymyxa betae, was first recorded in the UK in 1987. Recently, breeding lines and cultivars with partial resistance to the virus derived from the ‘Holly’ source of resistance have been developed and their suitability for use under UK conditions is explored in this paper. Virus multiplication in the roots of resistant lines exposed to severe disease pressure in glasshouse tests, when quantified by ELISA, was less than one third of that in susceptible controls. More recently developed resistant lines had a lower virus content, on average, largely due to a reduced frequency of susceptible individuals. There was no evidence for resistance to the vector, P. betae, in virus resistant lines. However, the proportion of viruliferous P. betae resting spores in the roots, estimated using the most probable number (MPN) technique, was reduced by at least one third in resistant lines compared with the most susceptible control. A novel line, containing an additional gene to that in ‘Holly’, was the most effective, reducing the infection level to 3% of that in the susceptible control. In two field experiments on severely infested sites, the rate of infection of a resistant line, when assessed by ELISA, was reduced by half compared with a susceptible cultivar and sugar yields of resistant lines were consistently 2–3 times higher than those of susceptible cultivars. In 41 trials on rhizomania‐free sites, several recently introduced resistant lines exhibited sugar yields and agronomic performance comparable to that of three selected high yielding, susceptible cultivars. Results are discussed in relation to the specific UK requirements for rhizomania resistant cultivars. One resistant line, Beta 805 (cv. Concept), fulfilled the requirements for widespread use to control the disease.     

广东肝血簇虫(Apicomplexa:Haemogre-garinidae)感染试验和生活史的研究

作者利用致乏库蚊(Culex fatigans)作为实验媒介,把寄生在灰鼠蛇(Ptyas korros)的广东肝血簇虫(Hepatozoon guangdongensis)感染到无虫的灰鼠蛇(渔游蛇(Natrix piscator)、三索锦蛇(Elaphe radita)和中国水蛇(Enhydris chinesis);观察其生活史。首次描述了由x裂殖体产生的小裂殖子,进入红细胞,经滋养体和幼小配子母体阶段发育成配子母体的过程,以及由y裂殖体产生的大裂殖子继续在内脏进行无性生殖的细节;在对广东肝血簇虫生活史进行研究的基础上,提出一种新的肝血簇虫在脊椎动物体内发育的模式和血液时期各期虫体划分的形态学标准。     

Selection of natural isolates of Trichoderma spp. for biocontrol of Polymyxa betae as a vector of virus causing rhizomania in sugar beet

The soil fungus Polymyxa betae, Keskin, besides being a root parasite, plays a role of a vector in dissemination of Beet necrotic yellow vein virus (BNYVV) causing rhizomania in sugar beet. An alternative to its chemical control is the application of antagonistic microorganisms suppressing proliferation of the fungal vector. In the present work, 66 Trichoderma isolates have been obtained from sugar beet plantations from diverse locations in Slovakia. The ability of the selected isolates to grow at low temperature (10 °C) and to suppress the colonization of roots with P. betae and the multiplication of BNYVV in roots under glasshouse conditions were tested. The roots of sugar beet seedlings growing in the BNYVV-infested soil were analyzed by serological ELISA test using monoclonal and polyclonal antibodies for the presence of BNYVV and checked microscopically for the occurrence of cystosori of P. betae. The efficacy of the selected strains to suppress the proliferation of BNYVV varied on the average between 21 and 68%. On the basis of these tests, candidate strains for practical application in biocontrol of sugar beet rhizomania were selected.     

PHENOTYPE FIXATION AND GENOTYPIC DIVERSITY IN THE COMPLEX LIFE CYCLE OF THE APHID PEMPHIGUS BETAE

The aphid Pemphigus betae typically shows a complex life cycle, with annual alternation between cottonwood trees, where it forms leaf galls, and herbaceous plants, where it lives on roots. Distinct phenotypes are associated with each phase. In a population in Utah, aphid clones vary in their tendencies to undergo the cottonwood phase of the life cycle, with certain clones rarely producing the winged migrants that initiate the cottonwood phase. To examine the extent of genotypic variability in life cycle traits and to determine the consequences of phase deletion for fitness in the remaining phase of the life cycle, I compared performances of sets of clones that differed in their tendencies to delete the cottonwood phase. Performances of 35 aphid clones were compared on root hosts in the laboratory, by quantifying size (a correlate of fecundity), developmental time, and mortality for clonal sublines. Clones that tend to delete the cottonwood phase and remain on roots developed faster, showed lower mortality, and were larger as compared to clones that tend to undergo an annual migration to cottonwood. These laboratory comparisons of individual clones agree with earlier findings from field experiments. Performance also varied significantly among clones within sets, with the set of clones not previously subjected to selection on root hosts showing higher variance than clones isolated following selection in the root-inhabiting phase. These data suggest that selection in the cottonwood phase opposes selection in the root phase. Thus, even in cases of polyphenism, in which divergent developmental pathways confer some independence of phenotypic expression in alternative phases, antagonistic pleiotropy limits adaptation within a phase. These findings on the correlates of intrapopulational variation in frequency of phase expression provide some of the best evidence for character release following reduction of a complex life cycle, and they support the hypothesis that the advantages of polyphenism may be limited by negative genetic correlations among fitness traits of alternative phenotypes.     

鼎突多刺蚁群体结构和生活史的研究

本文报告了鼎突多刺蚁(Polyrhachis vicina Roger)的群体结构和生活史。通过研究表明,鼎突多刺蚁一年发生一代,以蚁后、雄蚁、工蚁、幼虫和卵越冬。卵和幼虫在冬天发育停滞(或极慢)。到了春天,随着气温的上升,卵和幼虫又恢复正常发育。据室内人工饲养观察,卵的发育历期为23.8±2.5天(平均温度26℃)幼虫为20.4±4.4天(26℃),工蚁蛹为19.8±5.5天(27℃)。成长工蚁在5—11月出现;8—11月,雄蚁从蛹中羽化;10月,雌蚁从蛹中羽化。雌蚁分飞交尾后,进入邻近蚁巢或回到原巢,脱翅成为蚁后。蚁巢内存在着多后现象。     

黄鼠栉带绦虫和梳状莫斯绦虫的生活史研究

本文首次阐明黄鼠栉帮绦虫和梳状莫斯绦虫的生活史。实验证明这二种绦虫的中间宿主同是曲愎翼甲螨和小型肋甲螨。二者绦虫的成虫、拟囊尾蚴的形态特征有详细的描述与比较。此外,作者简要地讨论了spassky(1951)的锡带属、栉带属和莫斯属等的分类问题。     

卵形半肠吸虫的生活史研究(Trematoda:Mesocoeliidae)

本文首次阐明卵形半肠吸虫(Mesocoelium ovatum Goto et Ozaki,1930)的全程生活史。在福州,终宿主为黑眶蟾蜍(Bufo melanostictus),实验中间宿主为蜗牛,Bradybaena similaris和Cathaica ravida sieboldtiana。蜗牛吞食本吸虫卵而受感染。毛蚴在蜗牛肠管内孵化,而后钻到肠壁外发育为母胞蚴、子胞蚴、尾蚴和囊蚴各发育期。囊蚴可在子胞体中形成并可感染黑眶蟾蜍。本文讨论了半肠属(Mesocoelium)的演化系统问题及与外斜睾总科(Plagiorchioidea)中一些吸虫类群的关系。     

茭白冬芽的发育及抗寒性的形态学研究

节间横向维管组织是冬芽发育过程中所形成的特殊越冬维管结构,它们约起源于冬芽苗端倒数第五节间,其原始细胞由紧贴周缘维管束环外侧的一层薄壁细胞壁反分化而成。节间横向维管组织具有发达的木质部,但不呈V形,它们对加强冬芽发育时期及来年春天萌发期的水份和无机盐的运输起重要作用。冬芽发育过程中,其生长锥及幼叶的细胞发生了一系列细胞学变化,可归纳如下:①细胞分裂活动逐渐减弱,最终停止;②核仁周围的亮环越来越小,直至基本消失;③细胞所积累的淀粉颗粒逐渐增多增大;④在休眠期,细胞普遍产生质壁分离现象。这些细胞学变化可作为确定茭白冬芽抗寒性的有力依据。