Asexual reproduction in a population of a leafy hepatic species Lophozia silvicola Buch in central Norway

The seasonal pattern and degree of asexual reproduction of a boreal hepatic species, Lophozia silvicola Buch, were studied in a lowland population of the species in central Norway. Asexual reproduction was quantified as numbers of 1–2 -celled gemmae produced per individual shoot, with average production ranging from 1000 to 7000 gemmae per shoot. Despite a slightly increasing trend in early spring, average numbers of gemmae present on shoots were fairly constant during the growing season. Germinability of gemmae was high in early spring, but declined rapidly towards the end of the season, suggesting an increasing proportion of gemmae in the dormant stage in the diaspore bank. Despite repeated sampling, average shoot density remained fairly constant in L. silvicola colonies during the growth season. Gemma production did not correlate with shoot density. Local colonization efficiency was estimated as frequency of occupied substrate patches and proportion of substrate area occupied by L. silvicola in a 10×20 m plot. Colonizable substrates included decaying wood, bare soil and rock surfaces. Colonies of L. silvicola were small, and differences in colony sizes between the substrate types were not significant. Colonies were found in 38% of the substrate patches, but total cover was low, less than 0.1% of all colonizable substrate.     

On the morphology of Leiomitra mastigophoroides R.M.Schust. (Trichocoleaceae)

A better circumscribed morphological concept of Leiomitra mastigophoroides with its monospecific subgenus Leiomitra subg. Brachygyna from Dominica Island is given. Leiomitra mastigophoroides is characterized by the gynoecia restricted to short lateral branches, rare presence of ventral Acromastigum-type branching, presence of stem paraphyllia, and superficial cilia on marginal parts of the leaf disc. The species is newly confirmed from Peru in addition to Dominica Island. The monospecific subgenus Brachygyna is retained as an isolated element of the genus Leiomitra, because although L. mastigophoroides is unique in terms of the gynoecial position within the family Trichocoleaceae, other vegetative characters, except for the Acromastigum-type branches, are similar to other species of Leiomitra subg. Leiomitra.     

Ultrastructural studies of Henneguya rhamdia n. sp. (Myxozoa) a parasite from the Amazon teleost fish, Rhamdia quelen (Pimelodidae)

Henneguya rhamdia n. sp. is described in the gill filaments of the teleost fish Rhamdia quelen, collected from the Peixe Boi River, State of Pará, Brazil. This myxosporean produced spherical to ellipsoidal plasmodia, up to 300 microm in diameter, which contained developmental stages, including spores. Several dense bodies up to 2 microm in diameter were observed among the spores. The spore body was ellipsoidal (13.1 microm in length, 5.2 microm in width, and 2.5 microm in thickness) and each of the two valves presented a tapering tail (36.9 microm in length). These valves surrounded the binucleated sporoplasm cell and two equal ellipsoidal polar capsules (4.7 x 1.1 microm), which contained 10-11 (rarely 12) polar filament coils. The sporoplasm contained sporoplasmosomes with a laterally eccentric dense structure with a half-crescent section. Based on the data obtained by electron microscopy and on the host specificity, the spores differed from previously described Henneguya species, mainly in their shape and size, number and arrangement of the polar filament coils, and sporoplasmosome morphology.     

芸香草和西昌香茅挥发油的化学成分

芸香草和西昌香茅挥发油的化学成分张荣，苏中武，李承祜（第二军医大学药学院，上海２００４３３）关键词芸香草，西昌香茅，挥发油ＣｈｅｍｉｃａｌｃｏｎｓｔｉｔｕｅｎｔｓｏｆｅｓｓｅｎｔｉａｌｏｉｌｓｆｒｏｍＣｙｍｂｏｐｏｇｏｎｄｉｓｔｏｎｓ（ＮｅｅｓｅｘＳ...     

Abundance and distribution of a brown trout (Salmo trutta, L.) population in a remote high mountain lake

Brown trout (Salmo trutta) population of a remote high mountain lake (Lake Redó, Pyrenees, 2240 m above sea level) were studied during autumn using hydroacoustic techniques. This acoustic technique was for the first time used on fish at such high altitude in Spain. Sampling using multimesh nets fish catches and echosounding recording were carried out in September 1998. Mean density of fish was estimated to be 1.82 fish per 1000 m³ (597 fish ha^–1). The results exhibited mainly a littoral habitat, with the brown trout being preferentially in the 10–25 m deep layer, where the water was warmer and the richness and diversity of macroinvertebrates higher. The sampling by hydroacoustic technique found a length frequency range of fish higher than the multimesh gill nets but both of them estimated similar fish proportion for the common length range. The more frequent target strength (TS) for the population was –38 dB (TS range –37 to –39 dB). Good correlation was found between TS frequency distribution obtained by echosounding and that predicted by means of a model based on the log of the fish total length from multimesh gill nets captures.     

Effects of temperature and rainfall variation on population structure and sexual dimorphism across the geographical range of a dioecious species

The effects of climate (precipitation and temperature) on sexual dimorphism and population structure were analysed along a broad-scale environmental gradient covering the distributional range of the endemic dioecious species Corema album, along the west coast of the Iberian Peninsula. We aimed to assess distribution constraints and sex-related differences in demography and size associated with higher reproductive investment in females. Nine populations were chosen from across the geographic range of C. album and ten 10 × 10 m plots were established (10 m apart) along a 200-m transect. All male, female and non-reproductive shrubs were quantified within each plot and plant size, photosynthetic layer, height, sex ratio, population density and structure, and spatial segregation of sexes, under environmental conditions ranging from temperate to Mediterranean climate, were recorded and analysed. Increased aridity was related to lower population density and less structured populations, indicating an effect of higher temperature and lower precipitation on regeneration. Sexual dimorphism was influenced by climate, with size differences between sexes varying with aridity. However, demographic differences between sexes reflected in sex ratio deviations or the occurrence of spatial segregation were unrelated to any climatic variable, suggesting the existence of compensatory mechanisms that may counterbalance the higher reproductive effort of female plants. The results show the vulnerability of this endemic species to the increase in aridity expected in the southernmost limit of the biogeographical area due to global climate change, and demonstrate the importance of broad scale studies in the assessment of sexual dimorphism.     

R.M. Cowling,D.M. Richardson & S.M. Pierce (eds.) 1977. Vegetation of Southern Africa.

We determined the role of bird dispersal in seed and seedling dynamics of the tree Kalopanax pictus from 7 years of observing seed rain and seedling emergence in a broad-leaved deciduous forest in central Japan. We also performed an experiment on the influence of seed pulp on germination of seeds of K. pictus. Seeds of this species can lie dormant for several years, and this causes rather constant yearly seedling emergence in spite of irregular seed production. The spatial distribution of the seedlings that emerged each year (maximum distance from nearest conspecific seed-bearing tree of 90 m) was wider than that of gravity-dispersed seeds (max. distance of 37 m), suggesting seed dispersal by birds in winter. Emerged seedling densities at sites over 20 m from the nearest conspecific seed-bearing tree were highest in the spring of 1991, about half a year after the largest seed fall of the observation period. However, emerged seedling densities within 20 m from seed-bearing trees were highest in 1992, 1.5 years after the largest seed fall. These field observations may be explained by the experimental results on the effects of seed pulp on germination. Intact seeds germinate slowly at low germination rates, while seeds without seed pulp germinate quickly at high germination rates. Fallen seeds with seed pulp thus appear to form a seed bank near seed sources (temporal dispersal), while seeds scattered by birds appear to increase the possibility of reaching the present safe sites in distant areas with quick germination (spatial dispersal).     

Genetic diversity and population structure of Korean wild soybean (Glycine soja Sieb. and Zucc.) inferred from microsatellite markers

Korea is considered one of the centers of genetic diversity for cultivated as well as wild soybeans. Natural habitats of wild soybeans are distributed across the Korean mainland and the islands surrounding the Korean peninsula. In this study, the genetic diversity of 100 mainland Korean wild soybean accessions was evaluated by using 42 simple sequence repeat markers covering 17 soybean chromosomes. All analyzed loci were polymorphic and a total of 114 alleles were found. The observed average genetic diversity was low (0.4). The results showed that the 100 selected accessions did not exactly follow the geographical distribution. These results were further confirmed by the phylogeny inferred from five morphological characteristics (i.e., leaf shape, leaf area, plant shape, seed area, and 100-seed weight). Together, the genetic and morphological evaluations suggested conclusively that the selected population did not follow the geographical distribution pattern. The present study could provide useful information for the ex situ conservation and exploitation of wild soybean accessions in soybean improvement stratagems, and will aid in further understanding about the phylogeography of the species in the Korean center of diversity.     

nrDNA internal transcribed spacer data reveal that Rhodoplagiochila R.M. Schust. (Marchantiophyta: Jungermanniales) is a member of Plagiochila sect. Arrectae Carl

The monospecific genus Rhodoplagiochila, previously known only from the type collected in the Venezuelan Andes, has been collected at a second site close to the type locality. Up to now, generic status of Rhodoplagiochila has been accepted by most authors, but the taxon had been alternately assigned to Plagiochilaceae or Lophoziaceae. Phylogenetic analyses of nrITS sequences from Rhodoplagiochila and other representatives of the Plagiochilaceae clearly reveal the former to be in a clade with members of the Neotropical–Atlantic European Plagiochila sect. Arrectae. Within the Arrectae, Rhodoplagiochila is positioned in a robust clade made up of several accessions of Plagiochila bifaria. Morphologically, Rhodoplagiochila differs from other phenotypes of P. bifaria by the papillose leaf surface and a leaf margin which is ciliately toothed all-around. As an outcome of the molecular and morphological investigations, Rhodoplagiochila rosea is treated as a variety of P. bifaria, and the new combination P. bifaria var. rosea comb. et stat. nov. is proposed. In tropical America the family Plagiochilaceae seems to be represented only by Plagiochila.     

A study on population genetic structure of Oryza meyeriana (Zoll. et Mor. ex Steud.) Baill. from Yunnan and its in situ conservation significance

In order to determine genetic diversity ofOryza meyeriana (Zoll. et Mor. ex Steud.) Baill., 12 enzyme systems encoded by 17 loci were electrophoretically analyzed in 164 individuals of seven populations from Simao Prefecture, Yunnan Province, China. In comparison with those seed plants with the same life history and breeding systems, as well as the other species in the genusOryza, the species shows rather low levels of genetic diversity (A = 1.1,P = 8.0 %, Ho = 0.004 and He = 0.015) within populations and high genetic differentiation among populations. F_st was up to 0. 649, suggesting that 64. 9% of total genetic variability exists among populations. Considering high genetic differentiation among populations from a limited geographic region, most of the populations of the species are worth being protected, and therefore, great natural protection regions should theoretically be established in which a great deal of populations should be involved for developingin situ conservation management. Meanwhile, some priory localities forin situ conservation ofO. meyerzana in Yunnan Province, were proposed. Project supported by the Grant of the President of the Chinese Academy of Sciences.     

A study on population genetic structure of Oryza meyeriana (Zoll. et Mor. ex Steud.) Baill. from Yunnan and its in situ conservation significance

In order to determine genetic diversity of Oryza meyeriana (Zoll. et Mor. ex Steud. ) Baill., 12 enzyme systems encoded by 17 loci were electrophoretically analyzed in 164 individuals of seven populations from Simao Prefecture, Yunnan Province, China. In comparison with those seed plants with the same life history and breeding systems, as well as the other species in the genus Oryza, the species shows rather low levels of genetic diversity (A = 1.1, P = 8.0%, Ho = 0.004 and He = 0. 015) within populations and high genetic differentiation among populations. FST was up to 0. 649, suggesting that 64. 9% of total genetic variability exists among populations. Considering high genetic differentiation among populations from a limited geographic region, most of the populations of the species are worth being protected, and therefore, great natural protection regions should theoretically be established in which a great deal of populations should be involved for developing in situ conservation management. Meanwhile     

Contribution to the environmental ecology of Cryptogramma crispa (L.) R. Br. ex Hooker in the Alps

We studied the habitat characteristics in a number of Cryptogramma crispa stations throughout the Alps. Our objectives were: (1) to define the environmental ecology of C. crispa in the southern part of its distributional area in Europe; (2) to test the reliability of ecological indicator values of soil reaction, nutrient and dispersion status, light and temperature for this species. The habitats of C. crispa mostly consisted in coarse-grained stable screes (on rock slide deposits, talus cones, talus sheets, stone fields and moraines), within a broad elevation range with maximum frequency in the subalpine and lower alpine vegetation belts. At higher altitudes, C. crispa was mostly found on South-exposed slopes with high potential irradiance, whereas at low altitude it was most abundant on North-exposed rather gentle slopes formed of big boulders. The screes colonized by C. crispa were formed of acid metamorphic rocks or igneous rocks and had a coarse texture. The soil accumulated in the spaces among boulders had sandy texture and acidic reaction, with medium to high carbon and total nitrogen contents. Calcium lacks entirely in the soil. Our field data gave support to the Ellenberg–Landolt ecological indicator values of light and temperature, but not to those of soil reaction and soil nutrient content, for which some changes are proposed.     

Genetic diversity and population structure of Butea monosperma (Lam.) Taub.- a potential medicinal legume tree

Three molecular marker systems, Random Amplified Polymorphic DNA (RAPD), Inter-Simple Sequence Repeats (ISSR) and Sequence-Related Amplified Polymorphism (SRAP) were employed to investigate the genetic structure and diversity among the 14 natural populations of Butea monosperma collected from different geographical regions of India. Detected by 17 RAPD, 15 ISSR and 11 SRAP primer combinations, the proportions of polymorphic bands were 84.2 %, 77.2 % and 91.9 %, respectively, and the mean Nei’s genetic distances among the populations were 0.13, 0.10 and 0.13, respectively. Partitioning of genetic variability by Analysis of molecular variance (AMOVA) revealed that the high genetic diversity was distributed within the populations. AMOVA also revealed that the coefficient of gene differentiation among populations based on F_ST was very high irrespective of markers used. The overall gene flow among populations (Nm) was very low. Cophenetic correlation coefficients of Nei’s distance values and clustering pattern by Mental test were statistically significant for all three marker systems used but poor fit for ISSR data than for RAPD, SRAP and combined data set of all three markers. For all markers, a high similarity in dendrogram topologies was obtained, although some differences were observed with ISSR. The dendrogram obtained by RAPD, SRAP and combined data set of all three markers reflect relationship of most of the populations according to their geographic distribution.     

Internal genetic structure and outcrossing rate in a natural population of Araucaria angustifolia (Bert.) O. Kuntze

The internal genetic structure and outcrossing rate of a population of Araucaria angustifolia (Bert.) O. Kuntze were investigated using 16 allozyme loci. Estimates of the mean number of alleles per loci (1.6), percentage of polymorphic loci (43.8%), and expected genetic diversity (0.170) were similar to those obtained for other gymnosperms. The analysis of spatial autocorrelation demonstrated the presence of internal structure in the first distance classes (up to 70 m), suggesting the presence of family structure. The outcrossing rate was high (0.956), as expected for a dioecious species. However, it was different from unity, indicating outcrossings between related individuals and corroborating the presence of internal genetic structure. The results of this study have implications for the methodologies used in conservation collections and for the use or analysis of this forest species.     

Long-distance seed dispersal, clone longevity and lack of phylogeographical structure in the European distributional range of the coastal Calystegia soldanella (L.) R. Br. (Convolvulaceae)

Aim  To explore the relative effects of Quaternary climatic history vs. species-specific biological properties (high seed dispersability, high seed longevity, clonal growth) on phylogeographical structure in European Mediterranean and Atlantic Ocean and Black Sea material of the coastal dune plant Calystegia soldanella (L.) R. Br.
Location  Black Sea and European Mediterranean and Atlantic Ocean coasts.
Methods  Variation in amplified fragment length polymorphism was analysed at two different sampling levels. First, an entire-range sample from the Black Sea to the North Sea, including single individuals from sites evenly spread along this entire coast was analysed. Second, in a population-level sample, seven populations from the European Mediterranean and Atlantic Ocean coasts were analysed.
Results  Neither the entire-range nor the population-level sampling resulted in clear phylogeographical patterns. Instead, individuals from geographically distant areas were often genetically more similar to each other than individuals from the same area. Non-significant isolation-by-distance was found for both sampling approaches, and comparatively low levels of intrapopulational genetic variation were observed.
Main conclusions  The lack of phylogeographical structure in C. soldanella , in comparison with the clear phylogeographical patterns observed in other coastal plant species analysed previously, is postulated to be the result of the specific biology of C. soldanella . The combination of high seed longevity, high dispersability of seeds by sea water and clonal growth and probable high clone age are likely to be responsible for the observed absence of phylogeographical structure. This implies that extreme biological properties such as those shown by C. soldanella can either erase or prevent the formation of historical patterns of genetic variation.