蜂花粉系列研究

系统研究了蜂花粉营养成分及生物学功能，说明花粉属于完全营养食品并具有多种生物学作用。     

Virulence characteristics of a new race of the parasitic angiosperm,Striga gesnerioides,from southern Benin on cowpea (Vigna unguiculata)

An in vitro growth system was used to determine the virulence of two samples of Striga gesnerioides from Zakpota in southern Benin. Cowpea variety B301, previously considered resistant to all races of S. gesnerioides, was susceptible to both samples of the parasite. Two other cowpea varieties, 58–57 and IT81D-994, were totally resistant. Resistance in 58–57 was associated with a hypersensitive necrosis of infected roots, whilst IT81D-994 supported production of small S. gesnerioides tubercles with stems which failed to develop. Striga gesnerioides from southern Benin is the fourth race of the parasite to be identified, and the first with virulence on variety B301. The implications for breeding cowpeas with resistance to S. gesnerioides are discussed.Abbreviations IITA International Institute of Tropical Agriculture - LARS Long Ashton Research Station - SAFGRAD Semi-Arid Food Grain Research and Development     

Genetics of Resistance in Vicia sativa L. to Orobanche crenata Forsk.

The genetics of resistance of common vetch (Vicia sativa L.) to broomrape (Orobanche crenata Forsk.) was studied for two years by using the P₁, P₂, F₁, BC¹, BC₂, F₂ F₃, and F₄ generations obtained from crosses between resistant and susceptible lines. Resistant lines were selected by screening a world collection m a naturally infested plot. Resistance was tested both under field and greenhouse conditions. The best index to measure resistance was the number of emerged broomrapes per host plant. The results fit the additive-dominance model. The main component of the variation was additivity; dominance and interaction effects seemed to depend on the environment. When dominance is expressed, a low number is dominant over a high number of broomrapes per host plant.     

Characterization of host tolerance to Striga hermonthica

Summary One of the most promising control options against the parasitic weed Striga hermonthica is the use of crop varieties that combine resistance with high levels of tolerance. The aim of this study was to clarify the relation between Striga infestation level, Striga infection level and relative yield loss of sorghum and to use this insight for exploring the options for a proper screening procedure for tolerance. In three pot experiments, conducted in Mali (2003) and The Netherlands (2003, 2004), four sorghum genotypes were exposed to a range of Striga infestation levels, ranging from 0.0625 to 16 seeds cm⁻³. Observations included regular Striga emergence counts and sorghum grain yield at maturity. There were significant genotype, infestation and genotype × infestation effects on sorghum yield. The relation between infestation level and infection level was density dependent. Furthermore, the relation between Striga infection level and relative yield loss was non-linear, though for the most resistant genotype Framida only the linear part of the relation was obtained, as even at high infestation levels only moderate infection levels were achieved. The results suggest that for resistant genotypes, tolerance can best be quantified as a reduced relative yield loss per aboveground Striga plant, whereas for less resistant genotypes the maximum relative yield loss can best be used. Whether both expressions of tolerance are interrelated could not be resolved. Complications of screening for tolerance under field conditions are discussed.     

Plight of the bumble bee: Pathogen spillover from commercial to wild populations

Pathogen spread or ‘spillover’ can occur when heavily infected, domestic hosts interact with closely-related wildlife populations. Commercially-produced bumble bees used in greenhouse pollination often have higher levels of various pathogens than wild bumble bees. These pathogens may spread to wild bees when commercial bees escape from greenhouses and interact with their wild counterparts at nearby flowers. We examined the prevalence of four pathogens in wild bumble bee populations at locations near and distant to commercial greenhouses in southern Ontario, Canada. Bumble bees collected near commercial greenhouses were more frequently infected by those pathogens capable of being transmitted at flowers (Crithidia bombi and Nosema bombi) than bees collected at sites away from greenhouses. We argue that the spillover of pathogens from commercial to wild bees is the most likely cause of this pattern and we discuss the implications of such spillover for bumble bee conservation.     

黄圆蹄盾蚧寄生蜂的空间分布

 通过系统调查和室内饲养得出,云南省安宁市香樟上黄圆蹄盾蚧（Aonidiella citrina）的寄生蜂共有3种,即双带巨角跳小蜂［Comperiella bifasciata（Howard）］、盾蚧长缨蚜小蜂［Aspidiotiphagus citrinus(ctaw)］和双带花角蚜小蜂［Azotus perspeciosus(Girault)］。黄圆蹄盾蚧寄生蜂在香樟不同方位上的分布不同。在层次上,寄生蜂在外层的平均寄生率要比内层高;在方位上,寄生蜂在南面的平均寄生率最高,而在北面的平均寄生率最低,东西方位的平均寄生率差别不显著。通过Talor幂法和Iwao的回归分析对黄圆蹄盾蚧寄生蜂的空间分布型进行研究,得出的结果均一致,即黄圆蹄盾蚧寄生蜂种群在香樟上的空间分布型为均匀分布,且种群密度越高分布越均匀。     

圆背角无齿蚌寄生变态发育的初步观察

对圆背角无齿蚌的钩介幼虫寄生变态及稚贝发育过程进行了形态学观察和比较。实验表明:在水温(19.0±1.0)℃时,钩介幼虫需要约13天的寄生变态才能从鱼体脱落。圆背角无齿蚌在变态发育过程中其外部形态、内部器官、营养源发生了较大变化:成熟的钩介幼虫仅仅可以作简单的双壳开合运动;刚脱落的稚贝外部形态与幼虫相似,但已经可以依靠斧足进行爬行,并逐渐开始滤食;稚贝经过一段时间的生长,从幼虫壳内侧长出一对新壳,形态逐渐趋向于成贝,而幼虫壳则逐渐退化为壳顶。因此,圆背角无齿蚌的变态发育包括两个明显的阶段:第一阶段为寄生变态期;第二阶段为贝壳分泌期。     

四川省植物和食用菌寄生线虫种类名录

本名录记录的６９种植物和５种食用菌的线虫种类，３８属，分属于１１５种。其中，３７属，１１４种为四川省首次报道，３９种为国内首次报道。     

云南水稻根际土壤中的线虫种类鉴定

描述了云南水稻根际土壤中发现的3种植物寄生线虫燕麦真滑刃线虫A phelenchus avenae Bastian, 1865,多带螺旋线虫Helicotylechus multicinctus (Cobb, 1893) Golden, 1956和穿刺短体线虫Pratylenchus penetrans (Cobb, 1917) Chitwood & Otifa, 1952.这3种寄生线虫均为云南省新记录.     

昆明地区桔绵蜡蚧天敌昆虫种类研究初报

 桔绵蜡蚧(Pulvinaria citricola Kuwana)有捕食性天敌昆虫2种, 隶属于鞘翅目的瓢虫科; 寄生性天敌昆虫有8种,隶属于膜翅目小蜂总科的跳小蜂科和蚜小蜂科,其中日本食蚧蚜小蜂(Coccophagus japonicus Compere)为桔绵蜡蚧的主要寄生蜂,其数量占寄生蜂总数的71.2％,其数量变化将影响寄生蜂的整体消长变化。寄生蜂对桔绵蜡蚧的寄生率为40%.