中国污核衣属地衣(污核衣科)四个新记录种

报道了中国污核衣科Porinaceae污核衣属Porina地衣的4个新记录种,分别是小溪污核衣P.fluminea、黄褐污核衣P.fulvella、四室污核衣P.tetramera和萨氏污核衣P.thaxteri.提供了各种的形态描述、形态及解剖照片.研究标本采自山东、贵州、广东及海南等地,保存于中国科学院菌物标本馆(...     

Diversity of subaerial algae and cyanobacteria on tree bark in tropical mountain habitats

We report the species composition of subaerial epixylic algae and cyanobacteria from a South-East Asian mountain rainforest locality in Cibodas, West Java. Green algae (Trebouxiophyceae, Chlorophyceae, Trentepohliales) were dominant and Cyanobacteria were the second most frequent group. We specifically concentrated on the comparison of species composition of closed primary forest and open antropogenic spaces. Trentepohliales and Cyanobacteria dominated in open spaces with higher light intensities, whereas closed forest localities were dominated by trebouxiophycean coccal green algae. There was a significantly higher algal diversity in open spaces than in closed forest samples indicating the limiting effect of light on subaerial algal communities of closed tropical forests. A number of isolated strains and morphotypes probably represent undescribed taxa. Presented at the International Symposium Biology and Taxonomy of Green Algae V, Smolenice, June 26–29, 2007, Slovakia.     

The weight of the crust: Biomass of crustose lichens in tropical dry forest represents more than half of foliar biomass

In recent years, our ecological knowledge of tropical dry forests has increased dramatically. However, the functional contributions of whole ecosystem components, such as lichens, remain mostly unknown. In these forests, the abundance of epiphyte crustose lichens is responsible for the characteristic white bark on most woody plants, conspicuous during the dry season, but the amount of resources that the lichen component represents remains unexplored. We estimated lichen biomass in a Mexican tropical dry forest using the bark area of trees, the dry mass of lichens per unit area and the percentage of bark covered by lichens, together with previously known tree densities. The lowest 2.5 m of the forests main trunks contained 188 kg/ha of lichen biomass, with lichens covering 85% of the available bark for trees <12 cm DBH and 38% for trees >12 cm. Total epiphytic lichen biomass was 1.34–1.99 Mg/ha. Lichen biomass represented 61% of the foliar biomass in the forest. To our knowledge, this is the first time that a lichen biomass estimate is provided for an ecosystem in which crustose lichens are the dominant lichen growth form. Crustose lichens are typically considered to contribute little to the total lichen biomass and to be difficult to include in ecological analyses. The high lichen biomass in this ecosystem implies a significant ecological role which so far is unexplored. We suggest the crustose lichen component should not be underestimated a priori in ecological studies, especially in ecosystems with abundant lichen cover.     

地衣型真菌石果衣(疣孢菌科，子囊菌门)次级代谢产物的多样性

地衣能够产生大量的新型次级代谢产物,但以往对石果衣Endocarpon pusillum的研究中未能检测出任何次级代谢产物。然而,对其共生菌进行基因组测序发现其中含有14个沉默的PKS基因和2个沉默的NRPS基因。在此研究中,为激活其途径,使用了优化马铃薯培养基和大米培养基对石果衣共生真菌进行了培养。从优化马铃薯培养物中分离得到9个次级代谢产物,包括2个新的异吲哚-1-酮类化合物(1, 2)。而从大米培养物中分离到3个已知化合物和1个新的萘醌类化合物(9)。通过核磁共振和质谱数据确定了新化合物的结构。研究结果表明,大量地衣中未能检测出任何次级代谢产物,或仅能检测出少量次级代谢产物,可能与其基因组中的沉默基因有关。因此,通过对沉默基因的激活方法为地衣次级代谢产物资源的研究与开发开辟了有效途径。     

中国猫耳衣属地衣2个新记录种（英文）

报道了猫耳衣属的1个中国新记录种——具芽猫耳衣(Leptogium propaguliferum)和1个亚洲新记录种——糙腹猫耳衣(L.hypotrachynum)。此2个种均采自云南,其特征为上表面具皱纹,下表面裸露。文中提供了两种地衣的形态学和解剖学图片,并对其与形态相似种的区别特征进行了讨论。     

Dissociation and metal-binding characteristics of yellow lichen substances suggest a relationship with site preferences of lichens

Background and Aims: Many species of lichen-forming fungi contain yellow or orangeextracellular pigments belonging to the dibenzofurans (usnicacid), anthraquinones (e.g. parietin) or pulvinic acid group.These pigments are all equally efficient light screens, leadingus to question the potential ecological and evolutionary significanceof diversity in yellow and orange lichen substances. Here thehypothesis is tested that the different pigments differ in metal-bindingcharacteristics, which suggest that they may contribute to adaptationto sites differing in pH and metal availability. Methods: UV spectroscopy was used to study the dissociation and the pHdependence of the metal-binding behaviour of seven isolatedlichen substances in methanol. Metals applied were selectedmacro- and micro-nutrients (Cu²⁺, Fe²⁺, Fe³⁺, Mg²⁺, Mn²⁺ andZn²⁺). Key Results: All the pigments studied are strong to moderate acids with pK_a1values between 2·8 and 4·5. Metal complexationis common in the lichen substances studied. Complexation takesplace under acidic conditions with usnic acid, but under alkalineconditions with parietin and most compounds of the pulvinicacid group. The pulvinic acid derivative rhizocarpic acid formsmetal complexes both in the acidic and the alkaline range. Conclusions: Metal complexation by lichen substances could be a prerequisitefor lichen substance-mediated control of metal uptake. Assumingsuch an effect at pH values where the affinity of the metalfor the lichen substance is intermediate would explain the strongpreference of lichens with usnic or rhizocarpic acids to acidicsubstrata. Moreover, it would explain the preference of lichenswith parietin and some lichens with compounds of the pulvinicacid group either for nutrient-rich substrata at low pH or forcalcareous substrata.     

Reproductive mode and genetic variation suggest a North American origin of European Letharia vulpina

Our data on the intercontinental population biology of Letharia vulpina show an unexpected shift from a recombining North American population with unique haplotypes to genetically depauperate Swedish and Italian populations, each with many representatives of a single repeated haplotype. Analysis of eight loci in 47 individuals supported recombination in North American populations and showed almost no variation among European populations. We infer that a genetic bottleneck caused by limited long-distance dispersal accounts for the lack of genetic variation found in marginal populations. This lack of variation in the European populations makes it impossible to use population genetic means to distinguish clonal reproduction from self-fertilization or even outcrossing, but phenotype indicates that reproduction in the marginal populations is by clonal spread, via soredia and isidioid soredia.     

中国文字衣属一新记录种——长形文字衣（英文）

报道了文字衣属Graphis 1个中国新记录种,即长形文字衣Graphis elongata Zenker。该种的主要特征是具有伸长的线盘,果壳两侧炭化,子实层清晰状,子囊孢子横隔双透镜型,胞室12~16个,长55~80μm,无地衣化学物质。研究标本采自云南大围山,保存于聊城大学第一标本室(LCU-L)。文中提供了该种的详细描述和显微结构图片。     

OBSERVATIONS ON LICHENIZED AND FREE-LIVING PHYSOLINUM (CHLOROPHYTA,TRENTEPOHLIACEAE)1

Lichenized Physolinum Printz and free-living Physolinum from a dimly lit cave were studied from fresh collections and cultures, preserved specimens fixed in situ, and cultures that had persisted for 5 years in an environmental chamber. The branched filamentous association consists of a phycobiont and a characteristic ascomycetous mycobiont of one layer that completely ensheathes the algal partner. Epiphytic blue-green algae commonly occur attached to the mycobiont. The phycobiont, Physolinum monilia (De Wildem.) Printz, produces thick-walled, green spiny cells, some of which enlarge and contact the sheathing mycobiont cells; the phycobiont and mycobiont may then develop into new lichenized filaments. The hyaline mycobiont cells extend haustoria bound by the fungus wall deeply into the phycobiont chloroplasts. The epiphytes, Synechocystis-like colonies, are firmly attached to the outer walls of the mycobiont and are associated with several-celled extensions of the fungus beyond the apical phycobiont cells. Free-living Physolinum monilia filaments are branched and moniliform; the search-containing uninucleate cells are spherical to pyriform and have walls of cellulose. Each cell has a single massive chloroplast with plastoglobuli among tightly packed thylakoids. Except for their larger cells, P. monilia filaments appear to be identical to the phycobiont of lichenized Physolinum.