广州地区草坪线虫初步调查鉴定

为了解广州地区草坪线虫种类的分布情况，从广州市12个不同地点的运动型、观赏型、游憩型草坪和草圃采集草根样品，经贝曼漏斗法分离线虫，用TAF固定液杀死，依甘油慢法制作玻片，采用de Man公式测量计算，按T.Goodey和J.B.Goodey的分类系统进行鉴定，初步鉴定出线虫23种，其中6种为中国地理新记录。这些线虫种类中植物寄生线虫8种、植物病原线虫3种、食肉线虫5种、食菌线虫9种、食腐线虫6种，表明广州地区草坪线虫种类资源丰富，生物习性多样。     

Characterization of Pectolytic Erwinias as Highly Sophisticated Pathogens of plants

Erwinia carotovora and Erwinia chrysanthemi are the two most important soft rotting bacteria of commercially-grown plants. They are genetically diverse as is evident from polymorphisms in the pel and recA genes as well as in rrn, the ribsomal gene cluster. Subpopulations grouped into biovars, pathovars, or subspecies associated with various hosts and in different geographic regions suggest specialization in host preference and/or survival in diverse environments. Previous characterization of the pectolytic erwinias as opportunistic pathogens is being replaced by a realization that this group of bacteria exhibits a sophisticated repertoire of pathogenicity and virulence genes and regulators. The presence of an entire hrp gene cluster and associated type III secretion system, and global regulators which regulate virulence determinants such as exoenzyme production and motility, attest to a highly specialized pathogen. The fact that production of extracellular plant cell wall-degrading enzymes are coordinately activated by the diffusible signal molecule N-acyl-homoserine lactone in a population density-dependent manner may explain the occurrence of pectolytic erwinia in asymptomatic plant tissues. Transgenic plants expressing bacterial quorum-sensing signal molecules modulate this sensory system and exhibit resistance to soft rot infection. The pectolytic erwinias, being significant plant pathogens that are neither of quarantine concern nor a human health hazard while readily isolated from field sources, make an ideal model for investigating the genetic basis of plant pathogenesis and environmental fitness.     

Recent observations on leafy gall in Liliaceae and some other families

Corynebacterium fascians, which causes leafy gall, has been shown to be responsible for the unusual symptoms recently found in lilies. The symptoms are described and the different bacterial isolates compared by biochemical, serological and pathogenicity experiments. No evidence could be found for the existence of specialized strains even though considerable variation in virulence could be demonstrated. Although the role of variation in susceptibility of the different lily cultivars should not be underestimated, it would appear that high inoculum levels ofC. fascians in the soil may be largely responsible for these outbreaks.Also included in this study are the results of biochemical, serological and pathogenicity experiments ofC. fascians which has been isolated fromKalanchoe, Euphorbia, Brodiaea, Hebe andVerbascum.Samenvatting Reeds een aantal jaren was in lelies een woekering in stengelbollen bekend, die echter sporadisch voorkwam en economisch van weinig betekenis was. Tijdens de zomer van 1977 echter trad de ziekte op één enkel perceel zo ernstig op dat zeer aanzienlijke oogstderving het gevolg was. Behalve de stengelbol kan ook de hoofdbol misvormd zijn. Bovendien kunnen misvormde stengelbollen lange spruiten vormen, zgn. sabeltandvorming. Soms is het wortelstelsel gereduceerd; in de kas zijn verdikte stengels waargenomen. De ziekte staat nu bekend onder de naam woekerziekte.Door de PD te Wageningen en het LBO te Lisse werd de bacterieCorynebacterium fascians (Tilford) Dows. uit het zieke materiaal geïsoleerd. In gezamenlijk onderzoek werd nagegaan of de bacterie de veroorzaker is van bovengenoemde symptomen en of hier sprake is van een op lelie gespecialiseerde stam.Biochemische en serologische vergelijkingen tussen isolaten vanC. fascians uit lelie,Kalanchoe, Euphorbia, Brodiaeea, Hebe enVerbascum laten zien dat er zeer weinig verschillen bestaan. Alle isolaten reageren op een standaard antiserum met titers variërend tussen 1: 640–1: 5120.Een oriënterende inoculatieproef werd uitgevoerd op het LBO in 1977. Daarna werden op de PD 10 van de 25 isolaten uit lelie en 8 uit andere waardplanten getoetst op lelie, chrysant en lathyrus. Uit de inoculatieproeven blijkt, dat de bacterie de veroorzaker is van de waargenomen symptomen. Tussen de isolaten blijkt een groot verschil in pathogeniteit te bestaan (12–100% aantasting), zonder dat dit aan herkomst gebonden is. Het voorkomen van op lelie of andere waardplanten gespecialiseerde stammen is daarom niet aan te nemen.In hoeverre de hevige aantasting een gevolg is van een opbouw van de bacterie-populatie door een te nauwe vruchtwisseling en mechanische rooimethoden moet worden nagegaan.     

鸡油菌属真菌2个洲际间断分布种

 分别从云南省剑川县和香格里拉县采集到鸡油菌属(Cantharellus)真菌的东亚/北美/大洋洲间断分布种红鸡油菌(C. cinnabarinus)和东亚/北美间断分布种太平洋金色鸡油菌(C. formosus)。对两者进行了形态学描述和基于核糖体大亚基 (LSU nrDNA) 的分子系统学分析。研究结果表明中国原被定为C. cinnabarinus的标本代表着一个尚未发表的新分类单元,而本文报道的红鸡油菌为真正的C. cinnabarinus;太平洋金色鸡油菌为中国新纪录种,以其暗褐色的子实体区别其近似种C. cibarius。研究标本保存于中国科学院昆明植物研究所隐花植物标本馆。     

薹草属菱形果薹草组9种植物叶片的解剖学研究

利用石蜡切片法和叶表皮装片法对薹草属菱形果薹草组(Carexsect.Rhomboidales)9种植物进行叶片解剖结构特征观察。结果表明:9种植物的叶片解剖学特征总体上较一致,如横切面形状为"V"形或近"V"形,具气腔,中脉上方具泡状细胞,中脉维管束周围有不同程度的厚壁组织;上表皮细胞一般比下表皮细胞大;表皮下的叶肉细胞均出现不同程度的分化;叶表皮特征显示上、下表皮细胞均为长方形,垂周壁深波状弯曲,表现出近似种之间的相似性;表皮附属物为刺突状表皮毛;但不同种之间的叶解剖特征也有一定的区别,表现在泡状细胞层数、叶肉细胞分化层数和中脉维管束2端厚壁组织发达程度不同,气孔器在脉间成列或随机分布,气孔指数和气孔密度也有差异,可以作为区分种的依据。据此,本文提供了基于叶片解剖特征的9种植物分种检索表。     

Antelopes in The Pleistocene of Southern Africa

The study area of 2 786 ha contained over 200 springbok. The data were gathered during 78 separate day visits over four years. The most important social groups were (1) nursery herds of females and young; (2) harem herds similar to (1) but containing one adult male; (3) bachelor herds of males; and (4) solitary males. Other groupings, e.g. mixed adults of both sexes, were very uncommon. About twice as many adult females were to be found in harem herds as in nursery herds. The mean size of female herds (1 and 2 above) was between seven and nine animals (range 2-40) and of bachelor herds about five animals (range 2-14). Rutting and lambing tended to be seasonal. The lambing peak appeared to be about mid-September, though lambs were seen in every month September-April. It is suggested that lambing is correlated with the onset of Spring rains. Courtship activity seemed to be most intense during February-April. The adult sex ratio was about 85 males : 100 females.     

The Zoocartographic Approach to Anuran Ecology

This is the first detailed study of the post-natal development of Aethomys chrysophilus. Physical measurements were taken from 37 litters consisting of 116 young, and the behaviour of 37 young from 12 litters was observed. The physical development of the young is described and the weight and linear increases analysed. Litter size varied between one and five with an average of 3,1 young per litter for 37 litters. The minimum age of sexual maturity was approximately 82 days, and the shortest interval between litters was 26 days. Major behavioural changes were found at six, 12 and 26 days, and on this basis the post-natal development is divided into Neonatal (0-5 days). Transition (6-11 days), Infantile (12-25 days) and Juvenile (26-82 days) periods. Nipple-clinging dominated the early stages of development and the modifications of the incisors for this purpose are described. The parent-young relationship and mortality of the young are discussed. In addition, the post-natal development of A. chrysophilus is compared with that of three other South African murids, namely Aethomys namaquensis, Thallomys paedulcus and Praomys (Mastomys) natalensis.     

Gonadesiklus van die kroonkiewiet Vanellus coronatus op enkele binnelandse lughawens

Gonadal cycle of the crowned plover Vanellus coronatus at two inland airports. The gonadal cycle of 474 crowned plovers Vanellus coronatus collected from two inland airports during 1986/87 was investigated. Judged by the ovarian mass and the diameter of the largest visible follicle, a prominent activity peak occurs in the ovarian cycle of females during early summer. Judged by the mass, volume, histological development stages and diameter jof the seminiferous tubules of the testes, a corresponding but longer activity peak also occurs among males. Although the testes of immature males are generally smaller than those of adults, some individuals are potentially capable of reproduction within their first year of life. Evidently the breeding cycle of the crowned plover is influenced to a greater extent by the relative availability of food than by environmental factors such as day length, temperature or rainfall.     

Molecular identification of the powdery mildew fungus infecting rubber trees in China

Powdery mildew is a foliar disease of rubber trees. It is one of the most important leaf diseases in rubber plantations worldwide. The causal agent of this powdery mildew, previously known as Oidium heveae, has been identified under various names. To precisely identify the causal agents of this disease, 57 conidial samples were collected from 2013 to 2017 in Hainan, Yunnan and Guangdong provinces, the main rubber tree planting regions in China. Based on morphological observations using light and scanning electron microscopy, pathogenicity testing, and nrDNA ITS and 28S sequences, Erysiphe quercicola is suggested as the only causal agent of rubber tree powdery mildew in China.