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《Journal of bryology》2013,35(1):11-14
AbstractThe 1996 Chagos Expedition provided an opportunity to study the archipelago's bryophyte flora: 25 of the 55 islands were ecologically investigated, some in more detail than others, and lists and representative collections of mosses, hepatics and other cryptogamic plants were assembled for many of them. Although the islands have a low biodiversity for most of these groups, as would be expected in terms of their relatively young age, remoteness and small terrestrial surface areas, those organisms that are present are often found in abundance and play significant ecological roles. Where the status of taxa on islands has been determined, there appears to be a good correlation between bryophyte biodiversity and island size. Epiphytic bryophytes were not host specific and no epiphyllous species was observed. Biogeographic details are provided, where possible, for the 19 taxa recorded, of which four are new to the Indian Ocean and seven are new to the Chagos Archipelago. A new taxon, Cololejeunea planissima var. chagosensis Pócs var. nov. is described, and notes and illustrations of a probably new Lejeunea species are provided. 相似文献
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l-Threonic acid is a natural constituent in leaves of Pelargonium crispum (L.) L'Hér (lemon geranium) and Rumex x acutus L. (sorrel). In both species, l-[(14)C]threonate is formed after feeding l-[U-(14)C]ascorbic acid to detached leaves. R. acutus leaves labeled with l-[4-(3)H]- or l-[6-(3)H]ascorbic acid produce l-[(3)H]threonate, in the first case internally labeled and in the second case confined to the hydroxymethyl group. These results are consistent with the formation of l-threonate from carbons three through six of l-ascorbic acid. Detached leaves of P. crispum oxidize l-[U-(14)C] threonate to l-[(14)C]tartrate whereas leaves of R. acutus produce negligible tartrate and the bulk of the (14)C appears in (14)CO(2), [(14)C]sucrose, and other products of carbohydrate metabolism. R. acutus leaves that are labeled with l-[U-(14)C]threonate release (14)CO(2) at linear rate until a limiting value of 25% of the total [U-(14)C]threonate is metabolized. A small quantity of [(14)C]glycerate is also produced which suggests a process involving decarboxylation of l-[U-(14)C]threonate. 相似文献
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Résumé L'étude infrastructurale des corpora cardiaca de Locusta révèle l'existence de 3 types de fibres neurosécrétrices (portion neurohémale) et d'un seul type de cellules glandulaires (portion endocrine intrinsèque). Elle permet également d'envisager les modalités du rejet des sécrétions exogènes et endogènes.
Ultrastructural study of the retrocerebral neurosecretory system in Locusta migratoria migratorioides (R. et F.)I. The corpora cardiaca
Summary An ultrastructural study of the corpora cardiaca of Locusta migratoria migratorioides shows three neurosecretory fiber types in the neurohaemal part of these organs; only one cellular type constitutes the intrinsic glandular part of the corpora cardiaca. This study also shows sites of release of stored extrinsic neurosecretory material and of products elaborated by intrinsic glandular cells of the corpora cardiaca.相似文献
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《Cryptogamie Bryologie ☆》2001,22(2):145-148
Pseudoleskea artariae Thér. is recorded in three new Italian localities. A distribution map is reported for the Insubrian area (Italian-Swiss border). Morphological, ecological and chorological remarks are also given. 相似文献
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《Journal of bryology》2013,35(2):255-264
AbstractThe differences between Thysanomitrium Schwaegr. and Campylopus Brid. are discussed and regarded as insignificant. Therefore the six Thysanomitrium species reported from South America in the Index Muscorum are critically revised. T. yunqueanum C. Müll. and T. miserum Broth. are synonyms of Campylopus richardii Brid., and T. schiffneri Broth. and T. arenaceum Broth. are placed in the genus Campylopus as new combinations. Also T. arenaceum is reported from a new locality in Brazil. No material could be found in herbaria of T. wainoi Broth. and T. gastrotis C. Müll. 相似文献
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A lectin which agglutinates Zajdela hepatoma cells; rat red cells and lymphocytes, but no normal rat liver cells, was detected in the mucus, yielded by simple saline extraction, of the two snail species Arion empiricorum (Fér.) and Arion lusitanicus (MAB). The agglutination spectrum involves also human erythrocytes and red cells of several animal species. 相似文献
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中华蓑藓(Macromitrium cavaleriei Card.&Thér.)的形态变异强烈,为了解形态变异是否具有遗传学背景,本研究以采自浙南凤阳山、浙中金华北山、浙西北的天目山和江西庐山4个种群的中华蓑藓为材料,运用随机扩增多态性DNA(RAPD)探讨了中华蓑藓的遗传多样性。从100条随机引物中筛选出了15条有效引物,利用它们共获得183个条带,其中多态性条带占79·69%,中华蓑藓各种群间的Dice遗传距离为0·0732~0·1514。POPGENE32软件分析得到种的Nei基因多样性指数(H)为0·3378,Shannon指数(I)为0·5126,遗传分化系数(Gst)为0·1670;基因流(Nm)为2·4947;种群内遗传多样性指数为0·4055,占种群总的遗传多样性的79·11%,反映出研究区域内的中华蓑藓遗传变异大多数存在于种群内,中华蓑藓形态变异并没有多少遗传背景,很可能是生态环境因素引起的可塑性变异。聚类分析表明,中华蓑藓种群遗传距离与地理距离之间无直接相关关系,遗传多样性水平与物种特性和所处不同群落有关。虽然4个种群内的形态变异丰富,但是属于同一物种的范围。 相似文献
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Branco Christina W. C. de Assis Esteves Francisco Kozlowsky-Suzuki Betina 《Hydrobiologia》2000,437(1-3):71-81
Comprida lagoon is a shallow lagoon separated from the sea by a sand barrier. It has a brown-coloured freshwater with a high concentration of humic compounds. Its zooplankton community and limnological features were studied from March 1992 to December 1995. The lagoon was characterized by low transparency, acid water and relative constant physical–chemical features, except during sporadic marine entrances. The zooplankton, composed of holoplanktonic and meroplanktonic forms, consisted of 60 taxa. Eleven were permanent elements of the community: e.g. Bosminopsis deitersi, nauplii and copepodites of `Diaptomus' azureus. B. deitersi correlated positively with the lowest pH values and with the highest total dissolved nitrogen. Only four taxa correlated with chlorophyll-a concentration. Pigmentation in `D.' azureus is suggested to be as an energy reserve in a system where phytoplankton is probably light-limited. 相似文献
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《Cryptogamie Bryologie ☆》2001,22(1):47-51
List of the specimens of Hepaticae collected by R.P. Assel in Ivory Coast. Data include 11 species of Hepaticae recorded for the first time from this bryologically underexplored area. 相似文献
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M. Beauge 《Andrologie》1997,7(2):241-246
Intra-cavernous injection of vasoactive substances has dramatically modified the medical approach of erectile dysfunction. There are psychological and ethical difficulties to this therapeutic procedure, and it is likely that they do contribute to the high drop out rate encountered with this method. According to our clinical experience, we suggest several attitudes in order to facilitate patient's and partner's acceptance: ? There is no opposition between psychotherapy and intra-cavernous injection, they may be regarded as complementary. ? It is advisable to find means to reduce the fear induced by self injection, by reassuring the patient, and making the act easier by choosing the most simple injection material. The pharmacological action must be explained, as well as the side effects. ? Pharmacologically induced erection is often described as artificial, although intra-cavernous injection of vasoactive substances is a symptomatic treatment just as many other symptomatic treatments. It compensates a functional insufficiency, restoring a physiological state very close to normal as far as erection is concerned, but has no effect on sexual excitation, glans intumescence and the development of the ejaculatory climax reflex. The sexuel relation's erotization lays only within the couple, and remains entirely apart from any iatrogenic effect. ? Should the treatment remain secret? Inta-cavernous injection must not systematically be performed withtout the partner knowing about it, although the act should remain discrete and intimate. One should not encounter psychic or ethical difficulties in erectile dysfunction treatment with intra-cavernous injection of vasoactive substances, provided that it has been properly prescribed, well explained, and that it is part of a psychotherapy. It is doubtless that many refusals or therapy withdrawals are caused by poor or lack of technical initiation, on one hand, and by not taking into account the psychic and ethical aspects of the method, on the other hand. 相似文献
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Farshid S. Ahrestani Ignas M. A. Heitkönig Herbert H. T. Prins 《Plant and Soil》2011,349(1-2):319-330
This study’s goal was to better understand the growth pattern and limitations of the herbaceous production that supports South India’s rich large herbivore grazer assemblage. We conducted a fully factorial nitrogen and water (three levels each) treatment field experiment in the herbivore rich South Indian Western Ghats region to determine the seasonal pattern and the extent to which nitrogen and water availability limit herbaceous production. Graminoid production was found to be nitrogen limited. Despite low rainfall, additional water did not significantly increase overall biomass production nor extend growth in the dry season. Accumulated standing biomass was highest in the late wet season (November) and lowest in the dry season (May). Leaf nitrogen was highest in the early wet season (June) and lowest in the late dry season (March). Grazing had a positive effect on grass production by extending the growing season. Biomass production and graminoid leaf nitrogen concentration levels in the study area were similar to other tropical areas in the world. Also similar to other tropical large herbivore areas, the dry season poses an annual challenge for large herbivores in the study area —particularly the smaller bodied species—to satisfy their nutrient requirements. 相似文献
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A revision of fossil plants, with preserved structures, collected in the Upper Devonian of the Donetz Basin (Ukrainia) allows us to describe 2 Lycophyta. One of them is a new species: Colpodexylon (?) schopfii nov. sp. 相似文献
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Barbara Hickel 《Hydrobiologia》1988,161(1):41-48
The life cycle of Ceratium furcoides (Levander) Langhans which features sexual reproduction is described for the first time in situ from the lake Plußsee (northern West Germany). Anisogamic copulation occurs during the bloom period in July–August by incorporation of the male gamete by the female gamete, resulting in an overwintering planozygote. The planozygote develops into a benthic hypnozygote which germinates in spring to establish a planomeiocyte. The morphology and structure of the stages of the life cycle are described using light and scanning electron microscopy. 相似文献
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《Ethnos》2012,77(2):203-226
This paper examines forms of affliction that are understood as a kind of possession, all the more afflictive because they are experienced as ‘coming out of nowhere’. It is easier to specify the kind of learning associated with valued forms of possession, which occur in the context of ritual performances that entail informal apprenticeships. The sense in which afflictive possession is ‘learned’ is far more diffuse, and occurs much earlier than the point at which diagnosis occurs. This paper traces such learning to early forms of socialisation into gender, focusing on motility and bodily comportment, as central to the way in which the lived body of gender moves between different practical environments. In an environment that includes spirits and deities, female movement acts as guarantor, not only of social stability, but of cosmological order and disorder. 相似文献