中国重科一新属一新种(目:粉亚目)

本文记述重科一新属及一新种。     

旋扭山绿豆根瘤菌的分离与回接

用纯培养方法,从旋扭山绿豆(Desmodium intortum)根瘤中分离获得快生型和慢生型菌株,经回接试验表明这两种菌株都能使旋扭山绿豆结瘤,但结瘤数,固氮活性及植株生长都有差异.     

旋扭山绿豆快生型根瘤菌DI51菌株的研究

作者从旋扭山绿豆(Desmodium intortum)根瘤中分离到快生型根瘤菌DI51菌株.其生长速度在指数生长期为0.222代/时,在30℃下液体振荡培养30～48小时后明显混浊.容易利用蔗糖、蕈糖、鼠李糖、甘露醇和α—酮戊二酸等多种碳源,而不利用淀粉和纤维素.能利用磷酸氢二铵和谷氨酸等氮源,但利用酵母膏最好,不利用蛋白胨和尿素.在酵母膏—甘露醇或蔗糖或葡萄糖等培养基上降低pH使B·T·B(溴麝香草酚兰)变黄,而在酵母膏—柠檬酸、丙酮酸等培养基提高pH使B·T·B变蓝或深蓝.不产生3—酮基乳糖.7天使石蕊牛奶培养基pH升高和形成乳清环,而30天后变酸.研究结果表明DI51菌株是Desmodium属中一些种的一株快生型有效根瘤菌株.     

关于最大亏格达到下界的三连通三正则简单图

已被证明二连通三正则简单图的最大亏格至少为其圈秩的三分之一。且，当节点数可被三整除时，这个下界可以达到。本文提供了达到最大亏格下界的三连通三正则简单图所具有特殊结构，这就是三角形因子。     

Cienfuegia gen. nov. (Xyalidae) and Pseudoterschellingia gen. nov. (Linhomoeidae), two new genera of free‐living marine nematodes from the Caribbean Sea

Two new genera of nematodes are described from the Caribbean Sea. Cienfuegia gen. nov. belongs to the Xyalidae based on the position of the anterior gonad constantly left of the intestine, cuticle clearly striated, second and third circle of anterior sensilla inserted at the same level and buccal cavity surrounded by pharynx. The new genus is differentiated from other genera by the buccal cavity divided in two chambers and by the four cephalic setae being longer than the six outer labial setae. Within the Xyalidae, Cienfuegia shows most affinities with the genera Daptonema and Theristus. Pseudoterschellingia gen. nov. is placed within the Linhomoeidae on the basis of the presence of anterior rounded amphidial fovea, unarmed narrow buccal cavity, distinctive cardia and presence of apophysis of gubernaculum. Pseudoterschellingia is closely related to the genera Terschellingia and Terschellingioides, but is differentiated by the crypto‐spiral amphidial fovea, and conical buccal cavity surrounded by pharyngeal tissue.     

New taxa of the family Trochometridiidae (Acari: Heterostigmata) associated with insects from Iran

A new genus and two new species of mites of the family Trochometridiidae (Acari: Heterostigmata) are described from Iran: Neotrochometridium sensillum Hajiqanbar and Khaustov gen. nov., sp. nov. associated with two carabid beetles and Trochometridium iranicum Hajiqanbar and Khaustov sp. nov. associated with a halictid bee. We also present the first report of two previously described species. These findings provide the first record of the family Trochometridiidae from Iran. The chaetotaxy of tarsus I of the family is discussed and a key to world genera and species is provided.     

A new genus of hemibranchiate sphaeromatid isopod crustacean from tropical Western Australia

A new genus and species of marine sphaeromatid isopod is described from the North West Shelf (Indian Ocean) tropical Western Australia. Kranosphaera haptomela gen. nov. sp. nov. (Sphaeromatinae) is distinguished from other hemibranchiate genera by the strongly rugose and deeply pitted body surfaces, projecting epistome, uniramous uropodal rami, and in the male by modified pereopod 5 which is greatly expanded and 6 which has a coupling flange on the ischium. It is known only from the vicinity of the type locality.     

A remarkable new genus and species of Cynipoidea (Hymenoptera) from Papua New Guinea

During the course of a recent investigation into the phylogeny of the Cynipoidea (Fergusson, 1990) a new species was discovered which is unusually elongate and has a remarkably deep incision between the metanotum and propodeum. This species constitutes a new genus, Eileenella, which is described below.     

Progress and prospects of studies on Polymyxa graminis and its transmitted cereal viruses in China

Polymyxa graminis is a eukaryotic obligate biotrophic parasite of plant roots that belongs to a poorly studied discrete taxonomic unit informally called “plasmodiophorids”. P. graminis is nonpathogenic, but has the ability to acquire and transmit nine plant viruses which belong to genera Bymovirus and Furovirus and cause serious diseases in cereal crop species and also result in significant yield reductions in China and elsewhere. Genus Bymovirus contains barley yellow mosaic virus (BaYMV), barley mild mosaic virus (BaMMV), wheat yellow mosaic virus (WYMV), wheat spindle streak mosaic virus (WSSMV), and oat mosaic virus (OMV), and genus Furovirus contains soil-borne wheat mosaic virus (SBWMV), oat golden stripe virus (OGSV), and newly identified Chinese wheat mosaic virus (CWMV) and soil-borne cereal mosaic virus (SBCMV). All these viruses have been sequenced and their worldwide distributions have been studied. The viruses are protected by the environment within P. graminis resting spores that may remain dormant but viable for decades (probably until a suitable host plant is encountered). Spontaneous deletion mutants of SBWMV, OGSV and OMV are detected, and these deletion mutants are not transmissible by the fungus. The persistent, soil-borne nature of these diseases makes the use of virus-resistant crop varieties currently the only practical and environmentally friendly means to control them, and a large number of disease resistant germplasms have been screened.