Rapid in vitro propagation of Matteuccia struthiopteris (L.) Todaro – an edible fern

A rapid and efficient in vitro plant regeneration method was developed for Matteuccia struthiopteris (L.) Todaro (Ostrich fern). Side shoots, originating in meristems of sectioned rhizomes, were used as explant material. A very high rate of meristem multiplication was achieved by culturing the explants in half-strength MS liquid medium supplemented with 2.0 mg/l N-(4-Pyridyl)-N′-phenylurea (4-PU) and 0.5 mg/l thidiazuron (TDZ). Multiplication of the shoot primordia was faster in suspension culture than on solid medium. Rhizogenesis and growth of regenerants were best achieved on hormone-free one-quarter-strength MS solid medium amended with 0.4% agar and 1.0% activated charcoal. Regenerated plantlets continued to grow after transfer to soil in a phytotron. Received: 19 March 1998 / Revision received: 17 July 1998 / Accepted: 3 August 1998     

Proliferation of meristematic clusters in disposable presterilized plastic bioreactors for the large-scale micropropagation of plants

Summary Proliferation of meristematic clusters of several plants in an inexpensive airlift bioreactor system, consisting of a disposable presterilized light transmittable plastic film vessel is described. The optimal shape, size, and structural function of the disposable plastic bioreactor are based on the bubble column and airlift glass bioreactors. The disposable bioreactors are designed in a conical configuration with a single inoculation and harvest port and multiple use dispensing and mixing accessories. Shearing damage and foaming problems known to exist in bioreactors due to the plant's rigid cell wall and size were greatly reduced in the disposable plastic bioreactors. The disposable bioreactors were used for propagule proliferation and growth, using meristem and bud clusters of potato, fern, banana, and gladiolus. The clusters' biomass increased five-to eightfold over a period of 26–30 d, depending on the species. The clusters were separated mechanically by a chopper made of a grid of knives. The chopped propagules were inoculated to agar medium for further growth and developed into transplantable plants. In the case of gladiolus and potato, corms and tubers developed in a sucrose-elevated storage organ induction medium, respectively, after the initial formation of small shoots. The plantlets and storage organs were transplanted to an acclimation greenhouse and continued to grow with a 95–100% survival, depending on the species. Plant development was followed for a period of 16 wk in fern and 12–14 wk in potato, banana, and gladiolus and normal shoot and leaf growth was observed. The feasibility of large-scale liquid cultures for plant micropropagation is discussed.     

Microsporidia of the Genus Trachipleistophora—Causative Agents of Human Microsporidiosis: Description of Trachipleistophora anthropophthera N. Sp. (Protozoa: Microsporidia)

Trachipleistophora anthropophthera n. sp., was found at autopsy in the brain of one and in the brain, kidneys, pancreas, thyroid, parathyroid, heart, liver, spleen, lymph nodes, and bone marrow of a second patient with AIDS. The parasite is similar to the recently described T. hominis Hollister, Canning, Weidner, Field. Kench and Marriott, 1996, in having isolated nuclei, meronts with a thick layer of electron dense material on the outer face of their plasmalemma and sporogony during which spores are formed inside a thick-walled sporophorous vesicle. In contrast to T. hominis , this species is dimorphic as it forms two kinds of sporophorous vesicles and spores: Type I-round to oval polysporous sporophorous vesicle. 7-10 μm in size, usually with eight spores (3.7 × 2.0 μm), thick endospores, subterminal anchoring disc and anisofilar polar filaments forming seven thicker and two thinner terminal coils. This type of sporophorous vesicle is associated with 25-30 nm filaments extending into the host cell cytoplasm. Type II—smaller, bisporous sporophorous vesicle (4-5 times 2.2-2.5 μm) with two, nearly round, thin-walled spores, 2.2-2.5 × 1.8-2.0 μm in size, having 4-5 isofilar coils. No outside filamentous elements are associated with the bisporous sporophorous vesicle. Both types of sporophorous vesicles were common in the infected brain tissue and could be found within the same cell. The newly described species, together with T. hominis and previously reported Pleistophora -like parasites from human muscle, likely represent a group of closely related human microsporidia.     

Multiple colonizations of a remote oceanic archipelago by one species: how common is long‐distance dispersal?

Aim  It is well established that many groups of plants and animals have undergone long-distance dispersal, but the extent to which this continues beyond initial colonization is largely unknown. To provide further insight into the frequency of gene flow mediated by long-distance dispersal, we investigated the origins of the fern Asplenium hookerianum on the Chatham Islands, and present a review of the contribution of molecular data to elucidating the origins of this archipelago's biota.
Location  Chatham Islands and New Zealand. A. hookerianum is scarce on the Chatham Islands but common in New Zealand, some 800 km to the west.
Methods  We compared chloroplast trnL–trnF DNA sequence data from Chatham Islands' A. hookerianum with extensive phylogeographic data for this genetically variable species in mainland New Zealand.
Results  Our sequencing revealed the presence of two haplotypes in Chatham Islands' A. hookerianum . These haplotypes differed by four mutational events and were each more closely related to haplotypes found in New Zealand than to each other.
Main conclusions  Despite the rarity of A. hookerianum on the Chatham Islands, its populations there appear to derive from at least two long-distance dispersal events from New Zealand, these possibly originating from different areas. We suggest that long-distance transoceanic dispersal, and the gene flow it can mediate, may be more common than is generally appreciated.     

THALLUS MORPHOLOGY AND SPORE FORMATION IN CULTURED ERYTHROCLADIA IRREGULARIS ROSENVINGE (RHODOPHYTA,BANGIOPHYCIDAE)1

The discoid thallus of Erythrocladia irregularis is the result of a pattern of cellular divisions expressed by mono-and endospores; the latter are described for the first time in Erythrocladia. In nutrient enriched growth conditions the discoid thallus becomes a shapeless aggregate of unicells with a wrinkled wall surface, whose plane of division is unpredictable. The cells are able to produce monosporangia with a curved wall or they form eight-celled endosporangia. Chloroplasts have an internal pyrenoid, as is characteristic of the Erythropeltidaceae. The observation that E. irregularis can form either a colonial cluster of unicells or a discoid thallus would lead to the assignment of the genus to the Porphyridiales; however, since this order is reserved to organisms in which only the unicellular organization can be expressed, it is suggested to maintain Erythrocladia in the Erythropeltidales.     

土施糖类对丛枝菌根真菌侵染率和产孢的影响

丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)不能进行光合作用,需要宿主植物提供碳水化合物供其完成整个生命周期,添加外源物质调控AMF和宿主植物的关系被认为是一种可行的措施。通过盆栽实验种植番茄,探索土施不同糖类对摩西球囊霉Glomus mosseae的侵染率、产孢能力和功能(宿主植物生长和养分)的影响。结果表明,添加葡萄糖和蔗糖可提高接种了摩西球囊霉的番茄的地上部生物量以及磷、钾吸收量,但对地上部氮吸收量影响不显著;添加麦芽糖和淀粉对地上部生物量及氮磷钾养分吸收量的影响均不显著。添加糖类处理,土壤碱解氮均有下降趋势;土壤速效磷、速效钾随着地上部磷和钾吸收量增加有下降趋势。糖类添加对土壤有机质没有影响。添加不同糖类均提高了AMF的侵染率,其中添加蔗糖处理的侵染率较单独施用摩西球囊霉菌处理增加了114%。单独施用摩西球囊霉菌剂处理土壤孢子数为10个/g,添加葡萄糖和淀粉处理的孢子数均为8个/g,添加蔗糖和麦芽糖处理的孢子数均为11个/g,添加糖类均对AMF产孢无显著影响。     

香菇单孢杂交子代群体灰色关联度和ISSR分析

以香菇Lentinula edodes栽培菌株秋6和K95-1为亲本,通过单孢菌株配对杂交获得21个杂交子,观察杂交子及亲本菌丝体生长情况,进行栽培出菇试验。采用灰色关联度分析法,对9个正常出菇的杂交子从8个性状方面进行综合评价,结果表明,杂交子QK-8和QK-15关联度仅次于亲本秋6,农艺性状和子实体性状表现最好。采用ISSR技术对21个杂交子及亲本进行DNA多态性聚类分析,单孢杂交后代遗传分化十分明显,归于同一类群的杂交子在菌丝生长、子实体形态和农艺性状等方面常表现相似,ISSR分析能为优良杂交子初步筛选提供重要参考。     

广西石韦属七种植物叶片结构与孢子形态的比较研究

利用石蜡切片法研究了石韦属7种植物叶片的形态结构。结果显示:7种植物的叶片均属异面叶,且具典型的旱生叶结构;表皮大多为复表皮,表皮细胞排列紧密,主脉表面覆有厚角质膜,表皮毛为星状毛,由多细胞组成;气孔集中分布于下表皮,气孔类型为围绕型,气孔器略下陷;孢子两侧对称,极面观椭圆形,赤道面观豆形或超半圆形,表面饰纹为瘤状饰纹。石韦属7种植物的叶表皮细胞形状、表皮毛、表皮细胞垂周壁式样、气孔密度等解剖结构均表现出一定的种间差异,这些特征可为石韦属植物种间分类提供依据。     

大兴安岭落叶松林丛枝菌根真菌多样性

对大兴安岭落叶松林17个科26种植物丛枝菌根(AM)定居情况和丛枝菌根真菌(AMF)多样性进行了调查。在26种植物根样中形成典型AM定居的有23种,占88.46%。菌根侵染率为0～78.7%,平均为21.69%。在26种植物根样中,4种植物形成重楼型(Par-is-type)AM,占15.38%;10种植物形成疆南星型(Arum-type)AM,占38.46%;9种植物形成中间型(Intermediatetype)AM,占34.62%,3种植物未能形成AM菌根,占11.54%。从23种植物根围土样中分离到50种AMF,分属于5个属,其中无梗囊霉属(Acaulospora)24种占48%;球囊霉属(Glomus)19种占38%;内养囊霉属(Entrophospora)5种占10%;原囊霉属(Archaeospora)1种占2%;巨孢囊霉属(Gigaspora)1种占2%。Acaulospora和Glomus2属真菌在大兴安岭落叶松林土壤中占绝对优势;尼氏无梗囊霉(A.nocolsonii)和幼套球囊霉(G.etunicatum)是优势种。植物根围土壤中AMF的孢子密度平均为68.94个.100g-1风干土;AM...