Pollination systems in a warm temperate evergreen broad-leaved forest on Yaku Island

Animal pollination in a warm temperate evergreen broad-leaved forest was observed on Yaku-shima Island, south of Kyushu, Japan. Three groups of plants were categorized: canopy-flowering tree species, understory-flowering tree species, and climber and epiphyte species. Each of these formed different pollination systems. The canopy-flowering tree species had shallow, dish-shaped flowers and utilized various types of opportunistic pollinators. Most of the climber and epiphyte species had deep, tube-shaped flowers and specialized pollinators, although some climber species which bloomed in the canopy especially in winter, had opportunistic pollinators. The understory-flowering tree species had large dish- or funnel-shaped flowers and endothermic pollinators able to tolerate the dark and cold conditions under the canopy. The individual trees of canopy-flowering tree species produced large numbers of flowers simultaneously (mass-flowering) and had a well synchronized flowering period. Each canopy-flowering tree species segregated its flowering time from those of the anothers. Climber and epiphyte species and most of the understory-flowering tree species produced small numbers of flowers sequentially (extended flowering) and showed a long flowering period.     

The species of Ceramium (Ceramiaceae,Rhodophyta) around Taiwan

A taxonomic study was recently carried out on the species of Ceramium occurring around Taiwan. One hundred and fifty-one collections were made from January 1993 through spring 1994 at 75 sites distributed around the island. A total of thirteen species were found, including three for which names cannot currently be assigned: Ceramium aduncum, C. ciliatum, C. cimbricum, C. cliftonianum, C. flaccidum, C. gracillimum var. byssoideum, C. mazatlanense, C. nakamurai, C. paniculatum, C. tenerrimum and unidentified species 1, 2 and 3. Among these are three new records for Taiwan, C. cimbricum, C. cliftonianum, and C. mazatlanense. This paper summarizes the taxonomic characters of these species and presents a key for their identification. Distribution records of all 42 species reported from the tropical western Pacific are compared. This report is the first detailed record of the genus for Taiwan.     

Epidiatomic diatoms: An insight into interaction specificity

Little is known about direct interactions between diatoms. In this study, small diatoms attaching onto larger benthic and motile diatoms were considered. This phenomenon is commonly considered as epiphytism (with diatom epiphytes) although the exact nature of this interaction has not been investigated yet. The question that was addressed here is the specificity of the interaction, simply by observing species associations in their natural environment. A comparison of this special form of epiphytism was carried out between two sites, on a Mediterranean river and one of its tributaries. The results showed both host and epiphyte selection, but with some variability in species associations. This excludes the two alternative hypotheses that (i) large diatoms are a neutral substrate for smaller diatoms and that (ii) the interactions are strictly specific between two species.     

健康与凋萎病杨梅树体及根围菌群的差异

凋萎病是制约杨梅产业发展的严重病害。为了有效防控凋萎病,本研究分析了杨梅健康和感染凋萎病树体各部位及根表土和根围土中细菌和真菌群落的丰富度与多样性的差异。结果表明: 与健康树相比,病树根围土、根表土、根、枝干、枝皮和叶片的细菌和真菌丰富度均发生了显著变化,其中,根表土细菌和枝皮内真菌的丰富度和多样性均显著降低,而枝皮内细菌和根表土的真菌丰富度和多样性均显著升高。病树各部位及根表、根围土细菌和真菌的优势菌相对丰度在门、纲和属水平上发生了明显的变化,在病树枝干、根和根表土中的假单胞菌属及根表土、根围土中的镰刀菌属的相对丰度明显降低,病树根表土及根围土中青霉菌属的相对丰度明显增加。与凋萎病菌同属的拟盘多毛孢菌在病树根内显著减少,而在其他位置均大量增殖,其相对丰度与多数相对丰度较高的真菌呈正相关。本研究结果将为开发杨梅凋萎病的生态改良、培育健康树体和生物防治技术提供有效的理论依据。     

Occurrence of species of the genus Pityophthorus Eichhoff (Coleoptera,Curculionidae, Scolytinae) in?the?province of Quebec,Canada

Twig beetles in the genus Pityophthorus Eichhoff, 1864 include more than 300 species worldwide, with maximum diversity in tropical and subtropical regions. To date, approximately 50 species of Pityophthorus have been recorded in Canada, and these species are associated mainly with coniferous trees. Since 1981, no comprehensive study on this difficult taxonomic group has been conducted in Quebec, Canada, most likely due to their limited significance as forest pests. Based on data gathered from five years of field sampling in conifer seed orchards and compiled from various entomological collections, the distribution of Pityophthorus species in Quebec is presented. Approximately 291 new localities were recorded for the Pityophthorus species. Five species-group taxa, namely Pityophthorus puberulus (LeConte, 1868), Pityophthorus pulchellus pulchellus Eichhoff, 1869, Pityophthorus pulicarius (Zimmermann, 1868), Pityophthorus nitidus Swaine, 1917,and Pityophthorus cariniceps LeConte&Horn, 1876 were the most widespread. In contrast, Pityophthorus consimilis LeConte, 1878, Pityophthorus intextus Swaine, 1917, Pityophthorus dentifrons Blackman, 1922, Pityophthorus ramiperda Swaine, 1917, and Pityophthorus concavus Blackman, 1928 display a notably limited distribution. In addition, the first distribution records of Pityophthorus intextus and Pityophthorus biovalis Blackman, 1922 are furnished, and the subspecies Pityophthorus murrayanae murrayanae Blackman, 1922is reported from Quebec for the second time. Moreover, distribution maps are provided for all Pityophthorus species recorded in the province of Quebec.     

外寄生菌——煤污病菌研究进展

煤污病菌生活在寄主组织表面,形成黑色的污斑和污点,影响果实外观,降低商品价值。煤污病菌能够利用植物的外渗物,也可以分解表皮的蜡质层,属于外寄生菌(ectophyte)。本文综述了煤污病菌的多样性、病征类型、分类鉴定研究方法、寄主范围、地理分布及其研究价值等方面的研究进展。     

Structure,function and floristic relationships of plant communities in stressful habitats marginal to the Brazilian Atlantic rainforest

The Brazilian Atlantic rainforest consists of a typical tropical rainforest on mountain slopes, and stands out as a biodiversity hotspot for its high species richness and high level of species endemism. This forest is bordered by plant communities with lower species diversity, due mostly to more extreme environmental conditions than those found in the mesic rainforest. Between the mountain slopes and the sea, the coastal plains have swamp forests, dry semi-deciduous forests and open thicket vegetation on marine sand deposits. At the other extreme, on top of the mountains (>2000 m a.s.l.), the rainforest is substituted by high altitude fields and open thicket vegetation on rocky outcrops. Thus, the plant communities that are marginal to the rainforest are subjected either to flooding, drought, oceanicity or cold winter temperatures. It was found that positive interactions among plants play an important role in the structuring and functioning of a swamp forest, a coastal sandy vegetation and a cold, high altitude vegetation in the state of Rio de Janeiro. Moreover, only a few species seem to adopt this positive role and, therefore, the functioning of these entire systems may rely on them. Curiously, these nurse plants are often epiphytes in the rainforest, and at the study sites are typically terrestrial. Many exhibit crassulacean acid metabolism. Conservation initiatives must treat the Atlantic coastal vegetation as a complex rather than a rainforest alone.     

Vascular Epiphyte Communities in the Inner-Crown of Hyeronima alchorneoides and Lecythis ampla at La Selva Biological Station, Costa Rica

The community composition and percent cover of vascular epiphytes were examined in relation to photosynthetic photon flux density (PFD), temperature, vapor pressure, and tree characteristics in the inner-crown of two emergent tree species, Hyeronima alchorneoides and Lecythis ampla, at La Selva Biological Station, Costa Rica. A total of 53 species were found in a total sampled branch area of 32 m² in eight trees—four trees per species. Community composition varied both among individuals of the same tree species and between tree species. However, percent cover patterns of vascular epiphytes were significantly different between the two tree species; Hyeronima had a significantly greater percent cover of epiphytes than Lecythis . The higher percent light transmittance as well as lower humidity in Lecythis are likely causes of its lower percent cover of epiphytes.