不同海拔高度短穗兔耳草克隆生长及克隆繁殖特征

研究了青藏铁路和青藏公路沿线 5个不同海拔高度样地中短穗兔耳草克隆生长和克隆繁殖的特征.结果表明,不同海拔高度短穗兔耳草匍匐茎数量、匍匐茎长度、基株干重、匍匐茎干重和无性系分株干重等均存在极显著差异(P<0. 01);匍匐茎数量与海拔高度之间存在明显的负线性相关性(P=0. 046 4);匍匐茎长度、基株干重、匍匐茎干重、单位长度上匍匐茎干重、无性系分株干重和匍匐茎分株总干重 /基株干重比值均与海拔高度之间存在极显著的二次多项式相关性(P<0. 01),但匍匐茎长度、匍匐茎分株总干重 /基株干重随海拔高度的变化趋势与基株干重、匍匐茎干重、单位长度上匍匐茎干重、无性系分株干重随海拔高度的变化趋势相反.在短穗兔耳草分布的海拔范围内,其克隆繁殖和克隆生长有一个“最佳”海拔高度,远离这一高度,其克隆繁殖和克隆生长会受到一定限制. 图 6表 2参 18     

Effects of cadmium exposure on metal-containing amoebocytes of the oyster Ostrea edulis

Oysters, Ostrea edulis, were exposed to cadmium (0.1 mg l^-1) for up to 110 d (in 1982) under laboratory conditions in order to determine the effect of Cd exposure on blood amoebocytes. The results demonstrate that Cd-accumulation does not alter the total Cu and Zn concentrations in gill tissue. There was a decrease in the numbers of metal-containing amoebocytes, and electron microprobe analysis showed that this was largely due to a reduction in numbers of the mixed Cu/Zn-containing cells rather than in Cu-or Zn-containing cells. It is postulated that this response, which may involve the release of metals from amoebocytes into gill tissue, is a generalised stress response of this oyster. No evidence was found for the presence of a specific Cd-containing blood cell or Cd-binding protein in blood cells.     

Chemical camouflage of the slave-making ant Polyergus samurai queen in the process of the host colony usurpation (Hymenoptera: Formicidae)

Founding queens of the obligatory social parasite ant Polyergus samurai usurp the host ant Formica japonica colony. The aggressive behaviors of F. japonica workers on the parasite queen disappear after the parasite queen kills the resident queen. To determine whether the parasite queen chemically mimics the host ants, we examined the aggressive behavior of F. japonica workers toward glass dummies applied with various extracts of the parasite queen and host workers. The crude extracts and hydrocarbon fraction reproduced the host workers’ behavior to the live ants. The extracts of the post-adoption parasite queen, as well as the nestmate extracts of F. japonica, did not elicit the aggressive behavior, but the extract of the pre-adoption parasite queen triggered attacks by the host workers. The nestmate recognition of host workers did not change, regardless of contact with the parasite. The gas chromatography and gas chromatography–mass spectrometry analyses indicated that the cuticular hydrocarbon (CHC) profile of the parasite queen drastically changed during the process of usurpation. Discriminant analysis showed the successfully usurped P. samurai queen had colony-specific CHC profiles. CHC profiles of the P. samurai queen who killed the host queen were more similar to those of the host queen than the workers, while the P. samurai queen who usurped the queenless colony had a profile similar to those of host workers. These results suggest that the P. samurai queen usually acquires the CHCs from the host queen during the fight, but from host wokers in queenless host colonies.     

Opsonin-like molecule found in coelomic fluid of a sea cucumber, Holothuria leucospilota

Opsonins, a group of serum proteins present in vertebrates, are known to bind to the surface of many kinds of pathogens and tag them as targets for phagocytosis. Opsonin-like molecules have been suggested to exist in several invertebrates. In this paper, we report the discovery of a new opsonin-like molecule in the coelomic fluid of the sea cucumber Holothuria leucospilota. Opsonic activity in cell-free coelomic fluid was characterized by sodium dodecyl sulfate–polyacrylamide gel electrophoresis, two-dimensional electrophoresis and gel filtration. Phagocytic uptake of yeast cells and latex beads by amoebocytes was quantified by microscopic analysis. It was found that a 20 kdalton protein bound to and enhanced phagocytosis of heat-killed yeast cells. The results of Western blot analysis suggest that both amoebocytes and spherule cells produce this opsonin-like molecule. Received: 22 October 1998 / Accepted: 4 March 2000     

Growth and reproduction of the generalist opisthobranch Haloa japonica: effect of algal seasonality on growth rate

The life history of Haloa japonica (Pilsbry), especially the seasonality of growth and reproduction, was investigated from 1992 to 1995 on a flat rocky shore exposed at low tide at Kattoshi, Hakodate Bay, Japan. To estimate the effect of environmental seasonality on growth rate, we conducted two sets of field cage experiments in which algal food was controlled. H. japonica was shown to have an annual life cycle. Spawning occurred from late April to mid-July. Recruitment occurred in June. Simultaneously, large adults disappeared from the habitat. A rapid increase in wet weight of H. japonica was observed in early spring, and coincided with the bloom of the membranous green alga, Monostroma angicava. Under field cage experiments, individuals feeding on both M. angicava and Polysiphonia japonica grew faster than those feeding on only P. japonica. Growth rates of H. japonica feeding on only P. japonica, however, did not vary from February to April. These results suggest that seasonal variation in the algal community limits the growth of H. japonica in early spring at Kattoshi. This factor is relatively more important as a limiting factor on the growth of H. japonica than the physical environment in this season.     

Seasonal variations in leaf capturing of particulate matter, surface wettability and micromorphology in urban tree species

The seasonal changes in leaf particulate matter (PM) accumulation, surface wettability and micromorphology in urban tree species, including Sophora japonica (S. japonica), Platanus acerifolia (P. acerifolia) and Cedrus deodara (C. deodara), were studied during a single growing season. The three species showed distinct seasonal trends in PM accumulation, increasing from spring to autumn (or winter) even during the rainy season, but at different rates. During the study, the leaf PM retention amount of P. acerifolia, a species with ridged leaf surfaces, was significantly higher than that of S. japonica and C. deodara, species with waxy leaf surfaces. The contact angles of water droplets on leaves decreased with leaf age except on the abaxial surface of S. japonica, which remained non-wettable or highly non-wettable throughout the growing season; the decrease in the contact angle on adaxial surface of S. japonica was greater when compared with P. acerifolia and C. deodara. A significant and negative relationship existed between leaf PM retention amounts and contact angles on adaxial surface of leaves of all three species. The increase in wettability, probably caused when epicuticular wax was destroyed by mechanical and chemical abrasion, seemed to be the main factor leading to seasonal variations in leaf PM accumulation.     

Stable isotope analysis of two species of anguilliform leptocephali (<Emphasis Type="Italic">Anguilla japonica</Emphasis> and <Emphasis Type="Italic">Ariosoma major</Emphasis>) relative to their feeding depth in the North Equatorial Current region

Anguilla japonica leptocephali are transported from their offshore spawning area to their recruitment areas in East Asia, but their depth distributions, food sources and feeding are still poorly known. This study analyzed carbon and nitrogen stable isotope ratios of leptocephali of A. japonica, Ariosoma major and Ariosoma spp., and of particulate organic matter (POM), their likely food source, at five different depths in 2004–2009. We used mixing models to show that A. japonica appeared to be feeding at depths between 5 and 50 m, but sometimes deeper. A. major appeared to have a tendency of mostly feeding at depths of 50 m or shallower. Although the A. japonica and Ariosoma spp. collected in the same area during the leptocephalus stage appeared to have different feeding ecologies possibly related to different types of POM, their different depth distributions, sizes and transport histories may also help explain these differences.     

Annual cycle of biomass of a threatened population of the intertidal seagrass Zostera japonica in Hong Kong

The phenology and primary productivity of a population of Zostera japonica (Aschers. & Graebn.) threatened by the construction of Hong Kong's new international airport were studied over a 12-month period. The need to conserve the population, and the small leaf size of Z. japonica rendered traditional destructive or marking techniques inapplicable for percentage cover and biomass estimation. A nondestructive method based on image analysis techniques was therefore devised for repeated estimation of percentage cover, biomass and leaf area index. This technique, which involved random quadrat sampling, photographic recording and image analysis, was able to provide data on the three parameters with acceptable precision and was cost-effective in the field. Z. japonica demonstrated a strongly seasonal cycle of vegetative growth, with different patterns for leaf density (peak in March) and overall bed area (peak in June). Total (above- and below-ground) net primary productivity was estimated at between 344 and 688 g AFDW m⁻² yr⁻¹. Percentage cover of Z. japonica was negatively correlated with total suspended solids (TSS) in the water column while total bed area was negatively correlated with water salinity. Increased sedimentation associated with the new airport project was identified as one important factor affecting the growth of the seagrass, as TSS reached the high level of ≈1 g DW l⁻¹ during the first half of the study period. Sediment traps set in the beds also recorded potential sedimentation rates at between 2.89 and 14.5 mg cm⁻² d⁻¹. This high turbidity resulted in a sharp decrease in the density of Clithon spp., the dominant grazers of epiphytic algae on Z. japonica. Effects of sedimentation and shading on growth of Z. japonica were investigated by field manipulative experiments. Experimental increase of sedimentation rate and shade both resulted in larger decreases in percentage cover and above-ground AFDW compared with the control. Received: 3 March 1997 / Accepted: 14 March 1997     

Cytological study and immunohistochemical location of PSP toxins in foot skin of the ormer, Haliotis tuberculata, from the Galician coast (NW Spain)

The ormer, Haliotis tuberculata Linnaeus, 1758, is able to accumulate paralytic shellfish toxins (PST) in the foot side skin. Epidermal and secretory cells are described separately for the pedal side and sole epithelia, as notable differences have been observed. Melanin and photosynthetic pigment granules in the epidermal cells of the foot side epithelium give this skin its appearance and characteristic color. This epidermis also has abundant secretory cells containing at least three kinds of secretory granules. Conversely, the epidermal cells of foot sole epithelium do not have pigment granules, and the secretory cells are mostly subepithelial. Immunohistochemical reaction against PST (saxitoxin and its derivatives) showed that the toxins are located in specific cells of the foot side epithelium, which are distinct from the epidermal cells. Immunofluorescence also reveals toxins throughout many areas of the mucilage covering the epithelium, suggesting the secretory nature of the cells containing the toxins. These results do not show any apparent relationship between melanin or photosynthetic pigment granules and PST content. PST were not detected in the foot sole epithelium either immunohistochemically or by HPLC. Considering the toxic characteristics of ormers described in previous studies and the results presented here, the authors discuss the role of toxins retained or produced by the foot side epithelium Received: 25 July 2000 / Accepted: 7 November 2000     

Specificity of two temperate dinoflagellate–anthozoan associations from the north-western Pacific Ocean

Whilst many studies of symbiotic dinoflagellate diversity have focused on tropical reef environments, only a few have explored the degree and pattern of divergence of these endosymbionts at high latitudes. In this study, the genetic diversity and specificity of symbiotic dinoflagellates associated with two common anthozoan hosts in the north-western Pacific Ocean was studied in four different seasons during a period of 1 year. Partial nucleotide sequences of 28S and complete ITS1 ribosomal DNA regions were used to identify, genetically, the endosymbionts extracted from the scleractinian Alveopora japonica and the actinarian Heteractis sp. A. japonica harbours symbionts belonging to Symbiodinium of clade F, while Heteractis sp. associates with Symbiodinium of clade C. Moreover, no seasonal changes in the endosymbiont community were detected in these two associations during this study. This is the first evidence that these two temperate cnidarian–microalgae symbioses are stable. Furthermore, we tested the apparent specificity of the Heteractis sp.– Symbiodinium sp. clade C association, by performing alga-infection experiments with aposymbiotic hosts, and monitoring the uptake and persistence of homologous and heterologous symbionts. The findings confirm the association patterns detected in the field and show that Heteractis sp. only establishes a successful association with Symbiodinium cells of clade C, at least among the heterologous symbionts occurring in the study area. Our results are consistent with the idea that selective pressures in highly fluctuating temperate environments might have granted symbiosis-specificity an adaptive value.Communicated by T. Ikeda, Hakodate     

Contribution of morula cells to allogeneic responses in the colonial urochordate Botryllus schlosseri

Morula cells (MCs), ubiquitous ascidian cells which participate in alloimmune reactions, were studied in allogeneic and xenogeneic assays performed with Botryllus schlosseri (Pallas, 1766) colonies from the Mediterranean and the Pacific coast, USA. Experiments were performed on the morphological level, on blood cells sampled or vitally labeled in situ and on histological sections. In non-interacting B. schlosseri during blastogenic cycles A to C, MCs congregate in tentacles of the zooids' siphons. During the takeover phase of blastogenesis they disappear, appearing again in the siphons of the newly developed generation of zooids. In both compatible and incompatible allogeneic reactions their numbers in interacting ampullae increased fourfold within 2 h after first contacts, reaching up to 50% of the total blood-borne cells in ampulla lumens. In rejection processes most of these cells died, while in autologous or allogeneic fusions they disappeared from interacting ampullae within days of the reaction. During allogeneic rejections, we followed cases (up to 1 week) in which MCs crossed all morphological/physiological barriers between noncompatible colonies and entered the tunic matrices and blood systems of the interacting partners, forming successful microchimerism. In xenogeneic assays with Botrylloides sp., MCs concentrated at the xenogeneic boundary, but they never crossed into the other species. One week after fusion or rejection interactions, large numbers of macrophages clearing dead cells were found in contact areas. This is the first evidence for compartmentalization of specific cellular defense reactions in the tunicate circulatory system. Received: 23 October 1997 / Accepted: 17 February 1998     

A novel, sexually selected trait in poeciliid fishes: female preference for mustache-like, rostral filaments in male Poecilia sphenops

Female choice can often drive the elaboration of male traits, leading to the evolution of secondary sexual traits. In the Mexican molly, Poecilia sphenops (Poeciliidae), some males exhibit a mustache-like structure on the upper maxilla, the function of which has not been previously recognized. The mustache consists of epidermal outgrowths at the edge of the scales that appear to have no sensory function. Trait expression varies within as well as among populations of P. sphenops, but is not linked to male body size polymorphism. In mate choice experiments, female P. sphenops exhibited a visual mating preference for males with mustaches, suggesting that the trait may be sexually selected. Since the mating behavior of P. sphenops involves contact of the male’s snout and the female genital region prior to copulation, we hypothesize that the mustache may also convey tactile signals to the female.     

Origin and development of the amoebocytes of Nicolea zostericola (Polychaeta: Terebellidae) with a discussion of their possible role in oogenesis

Three types of amoebocytes are present at different stages in the life history of Nicolea zostericola (Grube, 1860): a granular amoebocyte or spindle cell and 2 agranular amoebocytes, designated Type I and Type II. The agranular amoebocytes originate from specific sites on the lateral parietal peritoneum of the coelomic cavity in all the thoracic and a few abdominal segments. The origin of the granular amoebocyte is unknown. In juvenile worms the Type I amoebocyte enters the coelomic fluid and accumulates lipid and glycogen, presumably derived from reserves stored in the parietal peritoneum. Near the beginning of the vitellogenic phase of oogenesis, the Type I amoebocyte disappears and a Type II form is produced by the peritoneum. Type II cells differ cytologically from the Type I form by containing extensive rough ER (endoplasmic reticulum), Golgi complexes and free ribosomes; they appear to synthesize protein for export. At the end of vitellogenesis and near spawning, amoebocytes undergo alterations which include the migration of the nucleus to a central position, the formation of stacks and whirls of rough ER cisternae, and the appearance of vacuoles throughout the cytoplasm. It is suggested that the agranular amoebocytes obtain nutrients from food reserves stored in the parietal peritoneum and transfer them to the oocytes for use in yolk synthesis. The function of the granular amoebocytes is unknown.Contribution No.37 from the Marine Science Institute, Northeastern University, Nahant, Massachusetts, USA.Contribution No. 50, Harbor Branch Foundation, Inc.     

克隆整合提高了入侵植物空心莲子草对北美车前的竞争力

选取北美车前Plantago virginica L.为竞争背景草,以空心莲子草Alternanthera philoxeroides（Mart.）Griseb.为研究对象,通过切断或保持其先端分株与后端分株间的匍匐茎连接,研究了克隆整合对先端分株生长以及竞争力的影响。结果显示：不管是否存在竞争,克隆整合显著提高了空心莲子草先端分株的生物量、总匍匐茎长度、叶片数目和分株数目,并降低了其对茎的生物量投资。此外,克隆整合显著提高了空心莲子草先端分株对北美车前的竞争力。种间竞争显著降低了空心莲子草的生长,但并没有显著影响其生物量分配。上述结果表明,克隆整合在一定程度上能够促进入侵克隆植物的生长和竞争力,从而可能潜在影响其入侵性。     

Comparative life-history study on sympatric hyperiid amphipods (<Emphasis Type="Italic">Themisto pacifica</Emphasis> and <Emphasis Type="Italic">T</Emphasis>. <Emphasis Type="Italic">japonica</Emphasis>) in the Oyashio region,western North Pacific

Life-history features of the sympatric amphipods Themisto pacifica and T. japonica in the western North Pacific were analyzed based on seasonal field samples collected from July 1996 through July 1998, and data from laboratory rearing experiments. T. pacfica occurred throughout the year, with populations peaking from spring to summer. In contrast, T. japonica were rare from autumn to early winter, but became abundant in late winter to spring. Mature T. pacifica females and juveniles occurred together throughout the year, indicating year-round reproduction. Mature T. japonica females were observed only in spring, and juveniles occurred irregularly in small numbers, suggesting limited, early-spring reproduction in this study area. Size composition analysis of T. pacifica identified a total of eight cohorts over the 2 years of the study. Due to the smaller sample size and rarity of mature females (>9.6 mm) and males (>7.1 mm), cohort analyses of T. japonica were not comparable. Laboratory rearing of specimens at 2°C, 5°C, 8°C and 12°C revealed that a linear equation best expressed body length growth by T. pacifica, while a logistic equation best expressed body length growth by T. japoncia. Combining these laboratory-derived growth patterns with maturity sizes of wild specimens, the minimum and maximum generation times of females at a temperature range of 2–12°C were computed as 32 days (12°C) and 224 days (2°C), respectively, for T. pacifica, and 66 days (12°C) and 358 days (2°C), respectively, for T. japonica. The numbers of eggs or juveniles in females marsupia increased with female body length and ranged from 23 to 64 for T. pacifica and from 152 to 601 for T. japonica. Taking into account the number of mature female instars, lifetime fecundities were estimated as 342 eggs for T. pacifica and 1195 eggs for T. japonica. Possible mechanisms for the coexistence of these two amphipods in the Oyashio region are also discussed.Communicated by O. Kinne, Oldendorf/Luhe     

Aspects of the feeding strategy of the predatory crab Scylla serrata

Scylla serrata in a South African estuary occurred more frequently in that part which had the highest number of prey organisms. Food location was by contact chemoreception, using the dactyls of the walking legs. Major prey groups were burrowing bivalves, attached bivalves and small crabs. s. serrata showed a preference for small crabs as prey. Because of their larger mass and higher energy content compared with other prey organisms, these crabs represented the major energy source of S. serrata in this area.     

Intracellular localization of vanadium in the fan worm Pseudopotamilla occelata

A very high level of vanadium was found to be contained in the polychaete worm Pseudopotamilla occelata collected in 1992–1993 from the Sanriku coast on the main island of Japan. The vanadium concentration (mean±SD=5500±1800 g g^-1 dry wt) in the worm's branchial crown which is composed of many bipinnate radioles was approximately 100 times higher than that (mean±SD=60±25 g g^-1 dry wt) in the trunk body. Electron probe X-ray microanalysis revealed that a large amount of vanadium was present in the outer potion of the epidermis of the bipinnate radiole. Analytical electron microscopy for a cryo-section of the bipinnate radioles indicated that vanadium was localized in electron-dense deposits in the apical portion of epidermal cells. From an examination of the fine structures, the locality of the electron-dense deposits were found to correspond to that of the apical vacuoles in the epidermal cells. It was concluded that most of the vanadium in P. occelata was contained in the vacuoles of the epidermal cells of the bipinnate radioles.     

Comparative sensitivity of various developmental stages of sea urchins to some chemicals

The sensitivity to some chemical agents was examined comparatively at sperm, fertilization, cleavage, blastula, gastrula, pluteus and metamorphosis stages of a sand dollar from Japanese waters (Peronella japonica) and a sea urchin from the Pacific coast of Australia (Heliocidaris erythrogramma). These agents included Cu sulphate, ABS and NH₃ chloride. Responses observed included departures from control rates of fertilization and developmental reduction at the attainment of first cleavage, gastrula, pluteus or metamorphosis. Developmental anomalies were noted at the fertilization, 2-cell, gastrula, pluteus and metamorphosis stages. Using minimum effective concentrations of the 3 chemicals at various developmental stages of P. japonica, it was found that sensitivity to chemicals varies from fertilization to metamorphosis. It seems that sperm activity is the most sensitive, and that fertilization and gastrulation are more sensitive than first cleavage, blastulation and pluteus formation. H. erythrogramma seems to show nearly the same responses to Cu, but is more sensitive at metamorphosis.Experiments conducted at the Seto Marine Biological Laboratory, Wakayama Prefecture, JapanExperiments conducted at School of Biological Sciences, the University of Sydney, Sydney, N.S.W., AustraliaContributions from the Seto Marine Biological Laboratory, No. 664     

Relationship between mouthpart structures and in situ feeding habits of species of the family Pontellidae (Copepoda: Calanoida)

Pontellid copepods were collected from the surface waters of a tidal front region in the Bungo Channel (the Inland Sea of Japan) in June 1986 to examine the relationship between the morphology of cephalic appendages and gut contents. In particular, two dominant species,Labidocera japonica Mori andPontellopsis yamadae Mori, were compared in detail. Large setae on the second maxillae ofL. japonica possessed two rows of setules at right angles to each seta along its inner margin except a terminal part which was serrated, whereas the inner margin of those setae ofP. yamadae was entirely serrated. Judging from the structure of the mouthparts, especially the second maxillae, the former species seems to employ both suspension and raptorial feeding modes, in contrast to the latter, which may use only the raptorial mode of feeding. InP. yamadae, the first maxilla and the maxilliped are also modified for carnivory. Gut content analysis supported the morphological evidence for feeding differences, and revealed thatP. yamadae is a carnivore preying mainly on copepodids whileL. japonica feeds omnivorously on copepod nauplii and phytoplankton particles. Since the mouthpart structures of congeners are quite similar to each other, the feeding behavior and habits might also be similar. Within the family Pontellidae, the generaAnomalocera, Calanopia, Epilabidocera, andPontella have mouthpart structures similar to those ofLabidocera, whereas the genusPontellina resemblesPontellopsis. Morphological similarities would suggest that the first group of genera employs both suspension and raptorial feeding modes, and thatPontellina is a carnivore likePontellopsis.