Microbial communities of lichens

The current state of scientific researches in lichen microbiology was reviewed. Analysis of the literature revealed the main areas and fundamental issues which refer to investigation of microbial consortia in lichen bodies. Special attention was focused on analysis of the prokaryotic community which plays a structural and functional role and is involved in metabolism and regulation of activity of the lichen symbiosis as a whole. In the review, for the first time the information on the yeast community, of which some members do not occur presently in other environmental substrates, was summarized. The data on the protozoa inhabiting lichen thalli were also provided. The reviewed literature enabled us to consider the growing and decaying thallus as a complex ecosystem with specific levels of regulation of abundance, taxonomic diversity, and activity of the members of five kingdoms: fungi, plants, protozoa, eubacteria, and archaea.     

Economic uses of lichens

Some of these lowly plants have long served as fodder for the reindeer herds of Lapplanders, while others have been the sources of industrial dyes, as those used in the manufacture of Harris Tweed cloth.     

Culture experiments with lichens

Fragments of several lichens were grown in the laboratory and developmental steps of growth and regeneration could be described. Different degrees of determination could be observed. The stages of podetial development inCladonia are easily distinguished and are reached after comparably short time. As they occur highly synchronized the results encourage further morphogenetic experiments.Dedicated to Prof. DrO. L. Lange on the occasion of his retirement as a tribute to his outstanding qualities as both a scientist and as a teacher and humane colleague.     

Reproductive strategies in lichens

Lichens employ two divergent strategies of reproduction, a sexual method through spore propagation and a derivative asexual strategy based on systems perpetuating the symbiosis by the dissemination of specialized diaspores. The distribution of these pathways in 24 families in the order Lecanorales is presented. Fruticose and foliose life forms have a greater representation of vegetative diaspores than crustose forms. It is hypothesized that chemical evolution occurred prior to the development of secondary asexual reproductive mechanisms. The derived vegetative morphologies have apparently outlasted their sexual ancestors, although a number of closely related "species pairs" are known, indicating the joint survival of ancestral sexual lines with secondary asexual offspring. Species using a vegetative strategy often have a greater world distribution than their sexual counterparts in foliose and fruticose groups. No clear pattern is apparent in crustose groups. The advantages of vegetative strategies are a greater survival for propagules and rapid invasion of new habitats. The separation of these strategies and the evolution of soredia and isidia represents a gradient in the evolution of taxa.     

地衣植物的经济意义

地衣是一类藻菌共生的低等植物 ,既不同于自由生活的真菌 ,又有别于自由生活的藻类。地衣作为一种先锋植物 ,不断的为其他生物开拓新土地。此外 ,它与人类的关系也很密切。本文就地衣植物的资源利用方面加以介绍。1　医药卫生我国将地衣入药已有悠久的历史 ,松萝、石蕊、石耳等都是沿用已久的中药。在国外 ,利用地衣治病也有许多文献记载。在中世纪 ,欧洲人就利用肺衣来治疗肺病和气喘 ,并用作补药、收剑剂和止血剂等 ;沟槽地衣被用来治疗头颤病 ;狗衣被用来治疗狂犬病 ;绿皮地卷则用来治疗小儿鹅口疮。在前苏联、瑞士、芬兰及奥地利等国家…     

Antibacterial substances from lichens

Crude extracts of many lichens and some lichen acids have considerable antibacterial activity, suggesting their possible value in chemotherapy and providing some justification for their folk-lore use in some countries against pulmonary disorders.     

Aliphatic compounds in some lichens

The presence of free fatty acids in Cetraria nivalis and Cladonia gonecha has been demonstrated. Saturated wax esters occur in Cetraria cucullata and C. nivalis, whilst free alkanols were found in C. cucullata. Triglycerides in C. nivalis were detected by their MS fragmentation patterns. Hexa(α-hydroxyisovalerate) is present in C. nivalis and Cl. gonecha, and the presence of ribitol in C. nivalis was demonstrated by identification of its acetonide in an acetone extract.     

Water-soluble phenolic compounds in lichens

The quantity and the qualitative composition (for some species) of phenolic compounds (PC) washed out of the intact thalli of lichens of the orders Peltigerales (the genera Peltigera, Solorina, and Nephroma) and Lecanorales (the genera Cladonia, Alectoria, and Cetraria) were studied. It was shown that the quantity of leachable PCs in Peltigerales was on average 2–3 times higher than in Lecanorales. At the same time, the extractability of PC from intact thalli by water was higher in Lecanorales than in Peltigerales: 48–88% and 34–70%, respectively, of the PC content in ethanol extracts from crushed thalli (i.e., of the total content of soluble PC). Water-soluble PC in the lichens Peltigera aphthosa, Solorina crocea, Cetraria islandica, Flavocetraria nivalis, Cladonia uncialis, and Cladonia arbuscula were represented by 7–12 phenolic compounds with similar qualitative composition in the species of the same order. The most part of water soluble PC were phenylpropanoids. All of the studied species showed the presence of p-hydroxybenzoic acid derivatives; vanillic and protocatechuic acid derivatives were found in Cetraria and Cladonia species, respectively.     

Ecological and biotechnological aspects of lichens

Lichens and the partners from three different kingdoms are both taxonomically and physiologically a very diverse group, which makes them interesting from both ecological and biotechnological points of view. A lichen is a mutual ecophysiological innovation in many extreme environments in which symbiosis seems to protect the partners. Lichen’s ability to grow in harsh environments can be advantageous, resulting in important ecological niches, or disadvantageous when lichens occupy and cause biodeterioration of cultural monuments. Recently, new candidate compounds for drugs, UVB protection, and antifreeze proteins for frozen foods were discovered. Lichens were also found to have potential in bioplastic degradation and prevention of desertification. Nevertheless, there is still large potential for further industrial screening and research on lichen products. Due to improved culture techniques of isolated symbionts, increased knowledge of their secondary metabolism and improved methods for solubilizing lichen metabolites, the screening and activity tests can be implemented more easily today than in the past.     

Growth and vitality of epiphytic lichens

 We tested the hypothesis that changed microclimate at induced forest edges causes reduced growth of epiphytic lichens. Two foliose, green algal lichens were transplanted to the lower canopy of a mature Picea abies forest at six distances (2, 6.25, 12.5, 25, 50 and 100 m) from a clearcut. The biomass growth in Platismatia glauca (6.2% in 16 months) was 41% higher than in Lobaria pulmonaria (4.4%). We found no growth reduction near the forest edge. In contrast, the highest growth in both species occurred within 12 m from the edge. Further, fluorescence and chlorophyll measurements showed that lichen vitality was unaffected by distance from edge. The light intensity was 4.3 times higher at the edge than in the interior during the growing season, but there were only minor differences in air temperature and relative humidity. Monitoring of thallus water content revealed clear differences in both number and length of wetting and drying cycles. However, the total time with water content sufficient for photosynthetic activity was only slightly higher at the edge. The data thus indicate that our gradient in microclimate was too small to significantly affect lichen growth, and that lichens are largely metabolically inactive when large edge-interior contrasts in microclimate occur. Lichen response to forest edge microclimate results from intricate interactions among several biotic and abiotic factors. Linking data on lichen growth, microclimate and thallus water content with physiological measurements provides a framework for future studies of the mechanisms behind abiotic edge effects. Received: 15 April 1996 / Accepted: 21 June 1996     

SSU rDNA phylogeny of cladoniiform lichens

To examine phylogenetic relationships among the "cladoniiform" lichenized fungi, i.e., the families Cladoniaceae, Baeomycetaceae, Icmadophilaceae, Stereocaulaceae, and Siphulaceae, and to provide evidence for the anticipated independent origins of podetia and pseudopodetia, we conducted phylogenetic analyses of SSU (small subunit) rDNA sequences from 39 lichen-forming fungi. These fungi represent all of the major growth forms of lichen associations, fruticose (including "cladoniiform"), foliose, and crustose. Our analysis suggests that lichen-forming fungi with a "cladoniiform" morphology arose multiple times within the ascomycetes. Additionally, each of the other thallus growth forms, crustose, foliose, and fruticose, have originated multiple times. It also seems to be clear that neither all podetiate nor all pseudopodetiate taxa form a monophyletic group. Therefore the term "podetium" should be restricted to homologous structures that are most probably limited to the genera Cladonia, Cladina, Pycnothelia, and allies. The "pseudopodetia" of Stereocaulon (Stereocaulaceae) and Cladia (Cladiaceae) may represent different states of the same homologous character. Our phylogenetic hypothesis supports the monophyletic origin of the order Lecanorales sensu stricto, including representatives of five suborders Cladoniineae, Lecanorineae, Teloschistineae, Agyriineae and Peltigerineae, but excluding representatives of the suborders Acarosporineae (Acarospora schleicheri and Megaspora verrucosa), Pertusariineae (Pertusaria trachythallina), and Umbilicarineae. The suborder Cladoniineae and the family Cladoniaceae both appear to be polyphyletic assemblages.