植物生活史对策的进化

植物生活史对策的进化班勇（中国林业科学院林业研究所,北京１０００９１）ＥｖｏｌｕｔｉｏｎｏｆＬｉｆｅＨｉｓｔｏｒｙＳｔｒａｔｅｇｙｉｎＰｌａｎｔｓ￥ＢａｎＹｏｎｇ（ＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆＦｏｒｅｓｔｒｙ,ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏ...     

四川55种鱼生活史型的研究

四川５５种鱼生活史型的研究刁晓明,罗一兵李波（西南农业大学水产系,重庆６３０７１６）（重庆大学计算机系,６３００００）ＬｉｆｅＨｉｓｔｏｒｙＰａｔｔｅｒｎｓｏｆ５５ＦｉｓｈＳｐｅｃｉｅｓｉｎＳｉｃｈｕａｎ￥ＤｉａｏＸｉａｏｍｉｎｇ;ＬｕｏＹｉｂｉｎｇ...     

Chlorosphaeropsis epidemica,spec. nova,eine neue Grünalge mit endophytischer Lebensweise

The new parasitic algaChlorosphaeropsis epidemica is a member of theChlorosarcinales and lives endophytically in the leaf-tissue ofPotamogeton species. It forms stacks of cells and appears in great numbers, especially in dying leaf-blades. Sexual reproduction is described for the first time in this genus. Apart from its endophytic way of life,Chl. epidemica is characterized by mononuclear cells with a parietal chloroplast of irregular thickness and with a few perforations, sometimes of complicated reticulate shape, and with 1–5 pyrenoids. The usually sphaerical gametes (respectively zoospores) are provided with two equal flagella, a parietal plastid, one pyrenoid and one stigma. In connection with the asexual reproduction the terms vegetative division and desmoschisis are critically discussed.

     

Laboratory culture and taxonomy of two species ofPedobesia (Bryopsidales,Chlorophyceae) in Japan

The morphology ofPedobesia lamourouxii andDerbesia ryukyuensis, both collected in Shimoda and the adjacent areas in central Japan, was studied from field specimens and laboratory cultures. Specimens which had the same morphology as EuropeanP. lamourouxii produced stephanokont zoospores which developed into either prostrate filaments or expanded discoidal thalli similar to those described by Feldmann and Codomier (1974) and Feldmannet al. (1975). Erect filament identical with the thallus found in nature developed directly from prostrate filaments. The specimens which had morphology similar to that ofDerbesia ryukyuensis described by Yamada and Tanaka (1938) also produced stephanokont zoospores which developed similarly to those ofP. lamourouxii. This species is, therefore, a member ofPedobesia, and it is made a new combinationP. ryukyuensis (Yamada et Tanaka) Kobara et Chihara, comb. nov.     

Population growth and economic development in Chiapas, 1524–1975

In a recent work on the Tzotzil (Maya) of Chiapas, Mexico, George Collier has suggested that indigenous groups frequently employ agricultural practices which are in obvious disequilibrium with their environment. As a result, he claims, such groups bring about the permanent destruction of their lands and forests. In this article, historical and demographic evidence is presented to demonstrate that the development of commencal agriculture outside of native communities, not overpopulation or technological conservatism within them, lies at the heart of such destruction. Finally, it is argued that anthropologists must consider the evolution of social classes in rural areas if they are to understand the difficulties which economic development entails.     

ÜberHydrianum viride (Characiaceae,Chlorophyceae), seine fortpflanzung und taxonomie

The little known epiphytic algaHydrianum viride was studied and pictured. The morphology and the variability of the vegetative cells are described in detail and compared with the observations of other authors. For the first time typical biflagellate zoospores of the chlorophycean-type have been recognized and the course of the asexual reproduction is studied. The residual protoplasm, that is the proximal half of the zoosporangium protoplast, growth up to the original size, typical for the genusHydrianum. The life cycle, especially the settling down of the zoospores, is described.Hydrianum viride belongs to the characteristic inhabitants of peaty waters; it belongs together with the host alga,Microspora loefgrenii, to the dominants of algal association of peat-springs. At last the taxonomic position and the synonyma of this organism are discussed.

     

Schistosoma incognitum from Cikurai,West Java,Indonesia

Schistosoma incognitum is reported for the first time from West Java, Indonesia where 84% of ricefield rats, Rattus argentiventer, were infected. Radix auricularia rubiginosa snails were intermediate hosts. The adult stage of the Javanese strain of S. incognitum and lesions in naturally-infected rodents are described. Rattus exulans, Rattus norvegicus and Mus musculus were experimentally infected. Epizootiology is similar to that described in other countries.     

Migration of Gasterophilus intestinalis larvae (Diptera: Gasterophilidae) in the equine oral cavity

Cogley T. P., Anderson J. R. and Cooley L. J. 1982. Migration of Gasterophilus intestinalis larvae (Diptera: Gasterophilidae) in the equine oral cavity. International Journal for Parasitology12: 473–480. Larvae of G. intestinalis pursued a specific migratory pathway within the equine oral cavity en route to the stomach. The larval migration included the following sequence: burrowing in the tongue mucosa, invasion of the interdental spaces, transitory attachment at the root of the tongue and movement to the stomach. The molt from first to second instar did not occur in the tongue, as commonly believed, but between the interdental spaces. Ninety five percent of the larvae invading the interdental spaces were associated with gingiva of the upper molars. SEM analysis revealed further details of the oral migration: (1) air holes excavated in the epithelium which connect with deeper burrows; (2) an intimate association between air holes and posterior spiracles of larvae; (3) precise impressions of larvae in tissue immediately surrounding the most recently formed burrows; and (4) initial larval entry into the tongue through the use of natural disruptions or healing lesions. Factors influencing the development of the oral migration are discussed.     

Simulation of the Viking biology experiments: An overview

Summary Several ground-based investigations have been carried out since the Viking biology results were received from Mars. Many of these have resulted in reasonable simulations of the Martian data, using as analogues of Mars either strong oxidants, UV-treated materials, iron-containing clays, or iron salts. The ambiguity between the GCMS experiment, in which no organic compounds were found on Mars, and the Labeled Release experiment, in which added organics were decomposed, may well be accounted for by these simulations.     

Laboratory culture and taxonomy of two species ofDerbesia (Class Chlorophyceae) in Japan

Two species ofDerbesia (Class Chlorophyceae),D. marina andD. tenuissima, have been studied for the purpose of obtaining a better understanding of their morphological details and life histories, using preserved and living specimens as well as laboratory cultures. The life histories of both species were completed in the laboratory, starting from both zoospores and zygotes. Specimens were collected at Asamushi, Aomori-ken, and Shimoda, Shizuoka-ken. Their life history types are fundamentally identical, zoospores giving rise upon germination toa Halicystis-phase, while zygotes grow into aDerbesia-phase. The thallus of theHalicystis-phase which alternates withD. marina is the same as that ofH. ovalis which grows in the northern regions of Japan. On the other hand, the thallus of theHalicystis-phase alternating withD. tenuissima is the same as that ofH. parvula known to occur in the temperate to subtropical regions of Japan. These results coincide with those obtained withD. marina andD. tenuissima in Europe, where the type localities of both species are located. Specimens assignable to these two species were collected at several localities in Japan and, as a result of detailed examination of the morphology, they are believed to be identical with eitherD. marina orD. tenuissima.