Screening Subterranean Clover (Trifolium spp.) Germplasm for Resistance to Meloidogyne species

This study was conducted to identify lines of subterranean clover (Trifolium spp.) with resistance to Meloidogyne arenaria (Neal, 1989) Chitwood, 1949, race 1; M. incognita (Kofoid and White, 1919) Chitwood, 1949, race 3; and M. javanica (Treub, 1885) Chitwood, 1949. A collection of 134 subterranean clover lines was evaluated and all had intermediate to high susceptibility. Root galling was negatively correlated with both seed and dry matter yields. Soil fumigation significantly reduced the nematode population in the field. Results indicate there is limited genetic resistance to root-knot nematodes among subterranean clover lines. Alternative sources of variation for this trait should be investigated.     

Germination, seedling morphology and establishment of Cotnbretum bauchiense Hutch. & Dalz. (Combretaceae)

ONYEKWELU, S. S. C, 1990. Germination, seedling morphology and establishment of Cotnbretum bauchiense Hutch. & Dalz. (Combretaceae). Cotnbretum bauchiense is a suffrutex with short, erect, usually herbaceous stems arising from a woody root stock. It appears in savanna soon after fire and (lowers within a few weeks. The fruits germinate in 5–6 days. The germination is cryptogeal. On germination the true radicle and the apparent radicle formed by fused cotyledon stalks push down into the soil, carrying the plumule with them. The cotyledon lamina and part of the fused cotyledon stalks remain above the soil. Both the apparent radicle and the true radicle produce roots. Below the soil at the joint of the apparent radicle and the true radicle the plumule produces 1–3 shoots which grow out to the surface of the soil. The underground portion of the shoot bears scale leaves, from which the plant regenerates when the aerial shoot is damaged by fire. This type of germination is an adaptation that ensures successful establishment in an environment that is subjected to fire.     

Distribution patterns of some subterranean Crustacea in the territory of the former Yugoslavia

A selection of the most representative distribution patterns of stygobiont animals is presented. The range of a genus may extend beyond the Dinaride karst, while some species exhibit a holo-Dinaric distribution. The mero-Dinaric distribution is organised in two vicarious centres (in the NW and SE) as well as an epilittoral and a paralittoral belt. The paralittoral distribution is a result of paleogeographic rather than present-day ecological conditions. Important differences between the interstitial faunas of Slovenia (and NE Italy) and Macedonia are probably the result of their different sources. Some other distribution patterns are discussed or summarized from the existing literature. The distribution patterns of this stygobiont fauna are extremely diverse, and are influenced by the geological complexity of the territory as well as by the richness of the fauna concerned. New distribution data for some Copepoda, Thermosbaenacea, and Amphipoda are appended.     

Neosteinernema longicurvicauda n. gen., n. sp. (Rhabditida: Steinernematidae), a Parasite of the Termite Reticuldermes flavipes (Koller)

A nematode isolated from the termite Reticulitermes flavipes (Koller) was identified and described as a new genus and species, Neosteinernema longicurvicauda. Primary distinguishing characters, by contrast to members of the genus Steinernema, were females having prominent phasmids, a curved tail longer than the body width at the anus, a spiral shape in juvenile-bearing females, and juveniles becoming infective-stage juveniles before emerging from the female; males having prominent phasmids, a digitate tail tip, a characteristic shape of the spicules (foot-shaped with a hump on the dorsal side), and 13-14 pairs of genital papillae, with eight pairs preanal; and infective juveniles having prominent phasmids and a filiform curved tail as long as the esophagus. Adult nematodes are found outside the termite cadaver. Diagnosis of the family Steinernematidae was emended to accommodate the new species.     

Ultrastructure and formation of the physogastric termite queen cuticle

The physogastric termite queen is the most striking example in insects of growth in size without cuticular moulting. This phenomenon has been studied with electron microscopy and histochemical tests in two species of higher termites, Cubitermes fungifaber and Macrotermes bellicosus. The abdominal hypertrophy (physogastry) is allowed by growth of the arthrodial membranes of the swarming imago. The growth is slow (over several years) but important: the cuticular dry weight is multiplied by 20 in C. fungifaber, by 100-150 in M. bellicosus. The termite queen cuticle arises from the transformation of the cuticle of the swarming imago or imaginal cuticle (unfolding and growing of the epicuticle, stretching of the endocuticle, resorption of the subcuticle) and from the secretion of a new endocuticle or royal endocuticle. The termite queen is the first example known in insects of epicuticular growth. In the physogastric queen, three cuticular types are observed: the rigid cuticle of the sclerites, the soft cuticle of the arthrodial membranes and the partially rigid cuticle of special structures, the neosclerites, which show both rigidity and growth. The fibrillar architecture varies according to the abdominal zones and the position within the cuticle. It appears to be determined by the forces arising from the musculature and the anisometric abdominal growth. The king does not become physogastric, although its cuticle is also modified.     

从白蚁中分离到具有纤维素酶活的贪噬菌

以黄胸散白蚁Reticulitermes flaviceps后肠为材料,分离培养具有降解纤维素能力的微生物,以进一步了解白蚁后肠微生物的种类。通过以羧甲基纤维素钠(CMC-Na)为唯一碳源的富集及选择培养基培养、筛选,获得一株具有纤维素酶活的菌株R3063。形态学鉴定、革兰氏染色观察及16S rDNA基因序列分析表明该菌株属于贪噬菌(Variovorax sp.)。目前尚未见贪噬菌具有纤维素酶活的报道。     

圆唇散白蚁补充生殖蚁的类型与建群能力

摘要: 【目的】为了探讨圆唇散白蚁Reticulitermes labralis补充生殖蚁对巢群稳定和发展的作用。【方法】对野外巢群进行调查研究, 及对婚飞成虫通过雌雄配对与补充生殖蚁隔离巢群进行人工饲养的对比研究。【结果】在野外巢群只发现1对原始蚁王蚁后, 而补充生殖蚁的数量最多可达到689头/巢。圆唇散白蚁有3种类型的补充生殖蚁, 即由工蚁转化来的无翅型补充生殖蚁、若蚁转化来的翅芽型补充生殖蚁和末龄若蚁羽化来的拟成虫型补充生殖蚁。实验室条件下婚飞配对群体和隔离群体建群1个月后的存活率分别为64%和96%。建巢初期婚飞配对群体的子代数目增长缓慢, 2个月时的群体数量为6.3±1.54, 10个月时的群体数量也仅为8.4±1.47; 而隔离建群补充生殖蚁2个月时的群体数量为52.4±6.44, 10个月时的群体数量为164.3±20.85, 都高于婚飞配对群体。 此外, 野外巢群的补充蚁后跟原始蚁后一样都具有发达的卵巢。【结论】在圆唇散白蚁中补充生殖蚁是白蚁巢群主要的繁殖力量, 也是建立新巢群的重要繁殖品级。