Photosynthesis of the cyanobacterial soil-crust lichen Collema tenax from arid lands in southern Utah, USA: role of water content on light and temperature responses of CO2 exchange

1. The gelatinous cyanobacterial Collema tenax is a dominant lichen of biotic soil crusts in the western United States. In laboratory experiments, we studied CO₂ exchange of this species as dependent on water content (WC), light and temperature. Results are compared with performance of green-algal lichens of the same site investigated earlier.
2. As compared with published data, photosynthetic capacity of C. tenax is higher than that of other cyanobacterial and green-algal soil-crust species studied. At all temperatures and photon flux densities of ecological relevance, net photosynthesis (NP) shows a strong depression at high degrees of hydration; maximal apparent quantum-use efficiency of CO₂ fixation is also reduced. Water requirements (moisture compensation point, WC for maximal NP) are higher than that of the green-algal lichens. Collema tenax exhibits extreme 'sun plant' features and is adapted to high thallus temperatures.
3. Erratic rain showers are the main source of moisture for soil crusts on the Colorado Plateau, quickly saturating the lichens with liquid water. High water-holding capacity of C. tenax ensures extended phases of favourable hydration at conditions of high light and temperature after the rain for substantial photosynthetic production. Under such conditions the cyanobacterial lichen appears superior over its green-algal competitors, which seem better adapted to habitats with high air humidity, dew or fog as prevailing source of moisture.     

Lichen diversity on steppe slopes in the northern Mongolian mountain taiga and its dependence on microclimate

Isolated steppes on sunlit southern slopes are a characteristic feature of the northern Mongolian mountain taiga. Lichen diversity of such steppe slopes was studied in the western Khentey Mountains, located between the Mongolian capital Ulan Bator and Lake Baikal. Functional types of lichen species were analyzed and measurements of microclimate were carried out as a first approach to figure out relevant site factors that control lichen distribution in the different habitat types of the steppe slopes. Such habitats include meadow steppe, siliceous rock and savanna-like Ulmus pumila open woodlands. Dominance of chlorolichens with either yellow or orange lichen substances (usnic acid, parietin, pulvinic acid derivatives) or melanin in the cortex, which absorb both ultraviolet radiation (UVR) and visible light usable for photosynthesis (PAR) suggests that effective protection against high solar irradiation is a crucial selective factor for lichens on the steppe slopes. The slopes are subject to high irradiation because of their steepness and because of the ultracontinental climate. In Betula platyphylla–Larix sibirica light taiga forest bordering the steppe on northern slopes, lichens with and without effective photoprotection co-occur. A second important factor, apparently influencing lichen distribution of the study area is water availability. Low precipitation, which falls in numerous small rain showers, combined with frequent dewfall in summer favors chlorolichens and explains the limitation of cyanolichens to particularly moist microsites, such as water runoffs on rocks or moss cushions on inclined or horizontal tree trunks. Ecophysiological measurements to prove these hypotheses on the significance of sunlight and water availability for lichen performance in the study area have not yet been carried out.     

Determinants of Lichen Diversity in a Rain Forest Understory

Change in lichen diversity is often used as a bioindicator to estimate effects of atmospheric pollution, but natural variation in lichen cover and species richness can be very high. We examined the top-down effects of spore-consuming ants and the bottom-up effects of nutrient and light availability on lichen diversity associated with the leaf surface of the rain forest understory plant, Piper cenocladum. Plots containing P. cenocladum were randomly assigned to treatments in factorial experiments that included high and low light levels, nutrient enrichment, and presence and absence of the ant mutualist, Pheidole bicornis . At the conclusion of the experiments, plants were harvested and size of leaves, secondary metabolite content (amides), epiphyll cover, and the species richness of the lichens (which comprised 85% of the epiphyll community) were quantified. Epiphyll cover (mosses, liverworts, and lichens) was greater on plants that had ant-mutualists and balanced resources. Lichen species richness was greater for plants with balanced resources, particularly for those with high light availability. Relationships between toxins and lichen cover and richness were weak and unclear. In this system, natural sources of variation were reliable determinants of lichen diversity and both biotic and abiotic influences were important.     

Surface hydrophobicity causes SO2 tolerance in lichens

BACKGROUND AND AIMS: The superhydrophobicity of the thallus surface in one of the most SO(2)-tolerant lichen species, Lecanora conizaeoides, suggests that surface hydrophobicity could be a general feature of lichen symbioses controlling their tolerance to SO(2). The study described here tests this hypothesis. METHODS: Water droplets of the size of a raindrop were placed on the surface of air-dry thalli in 50 lichen species of known SO(2) tolerance and contact angles were measured to quantify hydrophobicity. KEY RESULTS: The wettability of lichen thalli ranges from strongly hydrophobic to strongly hydrophilic. SO(2) tolerance of the studied lichen species increased with increasing hydrophobicity of the thallus surface. Extraction of extracellular lichen secondary metabolites with acetone reduced, but did not abolish the hydrophobicity of lichen thalli. CONCLUSIONS: Surface hydrophobicity is the main factor controlling SO(2) tolerance in lichens. It presumably originally evolved as an adaptation to wet habitats preventing the depression of net photosynthesis due to supersaturation of the thallus with water. Hydrophilicity of lichen thalli is an adaptation to dry or humid, but not directly rain-exposed habitats. The crucial role of surface hydrophobicity in SO(2) also explains why many markedly SO(2)-tolerant species are additionally tolerant to other (chemically unrelated) toxic substances including heavy metals.     

Calcium oxalate and sulphate-containing structures on the thallial surface of the lichen Ramalina lacera: response to polluted air and simulated acid rain

The formation of calcium‐containing structures on the thallial surface of the lichen Ramalina lacera (With.) J.R. Laund. in response to air pollution and to simulated acid rain, was studied in in situ and transplanted thalli. In situ thalli were collected from an unpolluted site and transplanted to heavily polluted and less polluted sites for a 10 month period. Additional thalli were treated either with double distilled water or with simulated acid rain. Scanning electron microscopy and infrared spectrometry revealed that thallial surfaces of in situ R. lacera samples collected in unpolluted sites were covered with two kinds of calcium oxalate crystals: whewellite and weddellite. These aggregates of calcium oxalate crystals appear to disintegrate and provide a crystal layer on the thallial surface. Infrared spectroscopy of powder scraped from thallial surfaces of transplants, retrieved from non‐polluted sites, showed the presence of whewellite and weddellite, whereas powders obtained from thalli retrieved from polluted sites contained whewellite, weddellite and gypsum. It is suggested that a certain fraction of the gypsum detected in crater‐like structures in transplants from polluted sites and in thalli treated with simulated acid rain is endogenous and should be considered a biomineral.     

Tree Species Composition Predicts Epiphytic Lichen Communities in an African Montane Rain Forest

The ecology of many tropical rain forest organisms, not the least in Africa, remains poorly understood. Here, we present a detailed ecological study of epiphytic lichens in the equatorial montane rain forest of Bwindi National Park (331 km²), Uganda. We evaluated all major lichen growth forms, including selected groups of crustose lichens. In 14 transects at elevations of 1290 m to 2500 m, we sampled 276 trees belonging to 60 species. We recorded all lichen species on each tree trunk between ground level and 2 m above the ground, yielding 191 lichen species in 67 genera, with a mean of 4.7 species per tree. We used non‐metric multi‐dimensional scaling to separate epiphytic lichen assemblages according to tree species composition and elevation. Structural equation modeling indicated that elevation influenced tree species composition and that tree species composition largely determined lichen species composition. Thus, elevation acted indirectly on the lichen assemblages. Further studies examining factors such as bark properties and lichen colonization ecology may clarify what determines the association between tree species and lichen assemblages. The link between lichen assemblages and large‐scale elevation patterns, as well as disturbance and regrowth histories, warrants further study. An analysis of lichen species composition on individual tree species that occur over large elevation ranges would distinguish the effect of tree species on lichen assemblages from the effect of elevation and thus climate. Our study highlights the limited extent of our knowledge of tropical epiphytic lichens.     

Water Distribution in Foliose Lichen Species: Interactions between Method of Hydration, Lichen Substances and Thallus Anatomy

Three lichens (Neofuscelia pokornyi, N. pulla and Xanthoriaparietina) from a semi-arid habitat were examined using low-temperaturescanning electron microscopy to evaluate the effects of hydrationmethod, lichen substances and thallus anatomy on the water distributionof hydrated thalli. In theNeofuscelia species, extracellularwater within the thallus was observed in association with cracksin its otherwise impervious upper cortex, while X. parietinashowed abundant extracellular water between medullary hyphae.Spraying the thalli followed by maintenance for 14–20h in a water-saturated atmosphere led to the disappearance ofthe external water film in X. parietina but not in the Neofusceliaspecies. Surface water was abundant in specimens of all speciesimmediately after spraying for 15 min. No extracellular waterwas observed inside the thallus 14–20 h after spraying,but after rinsing with acetone its presence was detected inall three species. Hydric strategy correlated with cortex hygroscopicity:X. parietina, an aero-hygrophytic species, had a more hygroscopicupper cortex than theNeofuscelia species, which are substrate-hygrophytic.The hygroscopicity of the upper cortex was linked with the amountof extracellular water in the thalline interior. Differencesbetween X. parietina and Neofuscelia in the polarity and distributionof their lichen substances agreed with species differences inthe presence and distribution of free water both as a film overthe surface and inside the thallus. Lichen substances appearto play a role in the maintenance of air-filled intrathallinespaces in species whose anatomy, habitat, or both, favour water-loggedconditions. Copyright 2000 Annals of Botany Company Lichen, water relations, semi-arid, lichen substances, LTSEM, thallus anatomy, extracellular water, Neofuscelia pokornyi(Körb.) Essl., Neofuscelia pulla(Ach.) Essl., Xanthoria parietina(L.) Th. Fr     

Determination of the relative uptake of ground vs. surface water by Populus deltoides during phytoremediation

The use of plants to remediate polluted groundwater is becoming an attractive alternative to more expensive traditional techniques. In order to adequately assess the effectiveness of the phytoremediation treatment, a clear understanding of water-use habits by the selected plant species is essential. We examined the relative uptake of surface water (i.e., precipitation) vs. groundwater by mature Populus deltoides by applying irrigation water at a rate equivalent to a 5-cm rain event. We used stable isotopes of hydrogen (D) and oxygen (18O) to identify groundwater and surface water (irrigation water) in the xylem sap water. Pretreatment isotopic ratios of both deuterium and 18O, ranked from heaviest to lightest, were irrigation water > groundwater > xylem sap. The discrepancy in preirrigation isotopic signatures between groundwater and xylem sap suggests that in the absence of a surface source of water (i.e., between rain events) there is an unknown amount of water being extracted from sources other than groundwater (i.e., soil surface water). We examined changes in volumetric soil water content (%), total hourly sapflux rates, and trichloroethene (TCE) concentrations. Following the irrigation treatment, volumetric soil water increased by 86% and sapflux increased by as much as 61%. Isotopic signatures of the xylem sap became substantially heavier following irrigation, suggesting that the applied irrigation water was quickly taken up by the plants. TCE concentrations in the xylem sap were diluted by an average of 21% following irrigation; however, dilution was low relative to the increase in sapflux. Our results show that water use by Populus deltoides is variable. Hence, studies addressing phytoremediation effectiveness must account for the relative proportion of surface vs. groundwater uptake.     

Epiphytic lichen diversity and its dependence on bark chemistry in the northern Mongolian dark taiga

Epiphytic lichen diversity was studied in a dark taiga forest of Pinus sibirica, Abies sibirica and Picea obovata in the western Khentey Mountains, northern Mongolia. Though most lichen species occurred on all three tree species, lichen diversity was higher on Abies and Picea than on Pinus. On branches, lichen vegetation differed less between tree species than on the trunk. The occurrence of many Parmeliaceae species with a hydrophilic surface and of many species producing the dibenzofuran usnic acid gives evidence of the low deposition of acidic pollutants in the study area. The Mn content of bark, which is known to limit at high values the abundance of epiphytic lichens in coniferous forests of Europe and North America, is apparently not controlling the spatial distribution of epiphytic lichens in the dark taiga of Mongolia. This is attributed to the dry and cold winters in Mongolia, as high Mn is especially leached from the surface of trees under moist conditions at temperatures around the freezing point, when the contact between water droplets and the tree surface is particularly intensive. Such moist and cold weather conditions are frequent in most parts of the northern coniferous forests of Europe and North America, but are rare events in the most continental parts of Asia, i.e. in Mongolia and eastern Siberia.     

模拟酸雨胁迫对杨梅幼苗水分生理特性的影响

选择浙江省典型亚热带经济植物杨梅为对象,通过盆栽试验研究了重度酸雨(pH2.5)、中度酸雨(pH4.0)和对照(pH5.6)处理对杨梅幼苗水分生理特性的影响.结果表明:季节、年份和酸雨对杨梅幼苗的光合速率均有显著影响,各处理中,夏季的差异大于春、秋季,pH4.0处理对光合速率有促进作用;季节、年份、酸雨,季节-年份交互作用以及三者交互作用对气孔导度均有显著影响,各处理在夏季的差异大于春、秋季,酸雨对气孔导度有抑制作用;季节、年份、酸雨及季节-年份和季节-酸雨两两交互作用对蒸腾速率有显著影响,各处理夏季的差异大于春秋季,且pH2.5处理对蒸腾速率的抑制作用最强;酸雨、季节-年份和季节-酸雨交互作用对水分利用率有显著影响,且pH2.5处理对水分利用率有一定的促进作用.     

Initial stages of lichen hydration observed by proton magnetic relaxation

The hydration of selected lichens ( Cladonia mitis , Cladonia bellidiflora , Cetraria islandica , Parmelia saxatilis , and Xanthoria parietina ) was investigated using gravimetry and proton magnetic free induction decays (FIDs).
The hydration from gaseous phase and dehydration to gaseous phase showed first-order kinetics. The amount of water which was non-removable in the air-dry state (relative humidity p / p ₀=9%) did not depend significantly on the lichen species and was found to be 5·6±1·0% of the d. wt.
The proton FID Gaussian component from the solid matrix of thallus structure, and two (or, depending on lichen species, one averaged) liquid signals coming from water tightly bound on the surface of thallus solid matrix and from loosely bound or free water, were recorded. The bound-water component was distinguished by its motional properties and by its proximity to endogenous paramagnetic centres present in solid matrix (presumably PS II reaction centres of the photobiont). Mild dehydration (from gaseous phase) could completely remove the loosely bound water fraction, leaving the system below the water percolation threshold and below the water clustering point, emphasizing the passivity of lichen response to desiccation shock. In the species in which the one average liquid component was recorded, bound water behaved similarly.
The hydration at which free water pool vanishes (Δ M / m ₀) and the relative (scaled to water) proton densities of solid matrix of lichen (β) were evaluated for all lichens investigated.     

ERUMPENT CEPHALODIA,AN APPARENT CASE OF PHYCOBIAL INFLUENCE ON LICHEN MORPHOLOGY1,2,3

On the upper surface of some specimens of the lichen Lobaria cf. crosa (Eschw.) Nyl. there are shrub-like growths which have a morphology similar to that of a free-living fruticose lichen, Polychidium umhausense (Auersw.) Henss., and contain a cyanophyte phycobiont, Nostoc. A few growths also contain scattered colonies of a chlorophyte phycobiont, in which case the lichen tissue locally assumes the foliose form characteristic of the parent Lobaria thallus. The differentiation of dorsiventral lichen cortices and the formation of a lax medulla and distinct algal layer are correlated with the presence of the green phycobiont. The lichen substances atranorin, gyrophoric acid, and 4-0-methylgyrophoric acid occur in both, the foliose L. erosa thallus and the fruticose tissue. It is suggested that the fruticose structures are erumpent cephalodia which are derived from the outgrowth of internal, cephalodia and should not be considered, to be epiphytic colonies of the lichen Polychidium.     

Effects of simulated acid rain on the foliar micromorphology and anatomy of tree tropical species

In order to correlate sintomatology with anatomical alterations caused by acid rain in leaves of tropical species, seedlings and saplings of Spondias dulcis Forst. F., Mimosa artemisiana Heringer and Paula and Gallesia integrifolia (Spreng.) Harms were exposed to simulated low-pH acid rain (pH 3.0). Control plants were submitted only to rain with distilled water (pH 6.0). The plants were exposed daily to the acid rain for 20 min for 10 consecutive days. Necrotic spots on the leaf blade occurred and most of the injuries onset on the epidermis in all species studied. S. dulcis displayed epicuticular wax erosion and rupture of epidermis. The abaxial surface of M. artemisiana was colonized by a mass of fungi hyphae and stomatal outer ledge rupture occurred. Some epidermal cells of G. integrifolia showed appearance similar to plasmolysis. The plants accumulated phenolic compounds in necrotic areas. Afterwards, leaves presented injuries in the mesophyll and collapsed completely. Cells surrounding the injured areas accumulated starch grains in S. dulcis. M. artemisiana showed more drastic symptom intensity in response to acidic rain. S. dulcis displayed visual symptoms similar to G. integrifolia, however, anatomical alterations were more severe.     

酸雨对中国陆地生态系统土壤呼吸影响的整合分析

通过整合分析(Meta-analysis)国内外公开发表的81篇模拟酸雨实验论文的2683条有效观测数据,量化了酸雨对中国3个主要陆地生态系统(森林、草地和农田)土壤呼吸(Rs)及其组分(自养呼吸(Ra)、异养呼吸(Rh))的影响。结果表明,酸雨显著降低了Rs(-9.6%)、Rh(-7.7%)和Ra(-11.7%);酸雨pH越低,Rs及其组分的降幅越大;野外实验对Rh和Ra的负效应大于温室实验。酸雨对Rs的负效应在农田最大(-14.7%),草地次之(-10.8%),森林最小(-8.0%);森林Rh、Ra对酸雨的响应与Rs一致,不同林型间差异不显著;草地Rh和Ra在酸雨处理下分别显著降低和增加。Rs、Rh与土壤pH显著正相关,与土壤有机碳(SOC)显著负相关;Rh和Ra分别与地上和地下生物量显著正相关。酸雨对Rs和Ra的负效应随纬度的增加而减弱,随年平均温的升高而增强,对Rs的正效应随年平均降水的降低而增强。研究表明,酸雨不仅降低了土壤pH,抑制了植物生长,减少了植物向土壤的碳输入,还降低了微生物活性,减少了Rh,导致SOC分解降低,因而未显著改变土壤碳库。研究结果将为全球变化背景下我国...     

酸雨对三峡库区4种植物幼苗光合生理及根际土壤的影响北大核心CSCD

近年来酸雨的酸性和频率越来越高,酸雨类型逐渐由硫酸型向硫酸-硝酸混合型及硝酸型转变。该研究以两年生马尾松、杉木、青冈和毛竹幼苗为试验材料,通过4个月的盆栽实验对幼苗进行硫酸型(SAR)、硝酸型(NAR)和混合型(MAR)酸雨及其各自3个酸雨浓度(pH 2.5、pH 3.5、pH 4.5)的处理,并以pH 5.7的蒸馏水为对照组,对植物的净光合速率、叶绿素含量、树种株高变化量以及植物根际土壤pH值和交换性盐基离子含量进行测定,以探究植物幼苗对模拟酸雨的敏感性及抗性特征,为酸雨受灾区的植被建设和抗酸树种的培育提供参考数据。结果表明:(1)不同浓度及类型酸雨在一定程度上能够抑制植物的净光合速率、阻碍叶绿素的合成,即酸雨浓度越高,植物净光合速率越低,叶绿素含量越少。(2)低浓度酸雨能够促进植物株高的增长,但随着酸雨浓度的增大,植物株高增长量受到严重抑制,且马尾松和青冈的表现最为明显。(3)植物根际土壤在低浓度酸雨胁迫下能够有效释放出盐基离子中和酸根离子从而降低酸雨的毒害,但随着酸雨浓度的增大,盐基离子含量不断衰减,土壤pH值逐渐减小。(4)杉木、马尾松、毛竹、青冈的平均隶属度值在不同酸雨类型作用下的表现不尽相同,总体上杉木对硫酸型和混合型酸雨的抗性最强,而毛竹能耐受硝酸型及混合型酸雨,青冈相比其他3种树种对酸雨的抗性最弱。研究发现,马尾松对硝酸型酸雨最敏感,且受胁迫的pH阈值为2.5~3.5,但对硫酸型酸雨表现出明显的抗性;杉木对3种类型酸雨的抗性较其他3种树种要强,毛竹抵抗硝酸型酸雨能力强于其他2种酸雨,而青冈对硝酸型酸雨的抵抗力强于其他2种酸雨且是抗酸能力最弱的树种,毛竹、杉木及青冈受酸雨胁迫的pH阈值为3.5~4.5;4种植物对酸雨的综合抵抗能力表现为杉木>毛竹>马尾松>青冈。     

酸雨对毛竹入侵阔叶林缓冲区根系形态及分布格局的影响

为明确亚热带毛竹与阔叶树根系对酸雨的适应策略,于2017—2018年在浙江省杭州临安天目山国家级自然保护区毛竹入侵阔叶林过渡区开展酸雨模拟试验,选取T1(pH=4.0)、T2(pH=2.5)、CK(pH=5.5)3个模拟酸雨梯度,分析不同强度酸雨作用下毛竹与阔叶树的根系变化。结果表明:T1对阔叶树根系形态指标具有显著的抑制作用(P<0.05),导致阔叶树根系的总根长、总表面积、总体积及和细根比根长分别下降了39.9%,39.4%,42.3%和16.2%;T2对毛竹和阔叶树根系指标均有显著的抑制作用(P<0.05),导致毛竹的根系总根长、总表面积、总体积及细根比根长分别下降了41.5%,42.9%,46.4%和15.1%,阔叶树根系分别下降了60.2%,63.3%,61.8%和20.5%。随着酸雨强度的增加,林内根系生物量密度减少,毛竹将更多的根系置于土壤表层。在水平方向上阔叶树根系则随离树距离的增加而逐渐减少,毛竹2—5 mm径级根系生物量在离竹20 cm,离树40 cm和20 cm之间差异显著(P<0.05)。pH、有机质、可溶有机碳、碱解氮、有效磷和速效钾对毛竹的...     

Lichen chemistry and selective grazing by the coleopteran Lasioderma serricorne

Part of the Lichenological Herbarium of the University of Trieste (TSB) was infested by Lasioderma serricorne, a polyphagus coleopteran. 1440 samples of 50 lichen species with different chemistry (Parmelia s.lat., Physcia s.lat.) were analyzed in order to assess whether the lichen diet of the insect was species- and especially lichen-chemistry-selective. Multivariate analysis indicates a significant negative correlation between the presence of some lichen substances and grazing phenomena. Atranorin, calcium oxalate, fumarprotocetraric acid, gyrophoric acid, lecanoric acid, skyrin, usnic acid and zeorin play an antiherbivorous role.     

DIFFERENTIAL RESPONSES OF PLANT FOLIAGE TO SIMULATED ACID RAIN

Experiments were performed to show the responses of foliage of several clones of Tradescantia sp., Pteridium aquilinum, Quercus palustris, and Glycine max to simulated acid rain. These experiments were performed to (a) predict the relative sensitivities of foliage of these plants to acid rain, and (b) identify leaf surface and anatomical alterations to simulated acid rain that may be used to diagnose acid rain injury. Plants were exposed to simulated rain at pH levels of 5.7, 3.4, 3.1, 2.9, 2.7, 2.5, and 2.3. Sporophyte leaves of bracken fern {P. aquilinum) were most sensitive to simulated acid rain among the species tested. About 10% of the surface area of older leaves of P. aquilinum was injured after exposure to 10 rainfalls at pH 2.5 (a single 20-min rainfall daily). Foliage of pin oak (Q. palustris) exhibited less than one-percent leaf area injury after exposure to simulated rain at pH 2.5 after 10 rainfalls (one 20-min rainfall daily). The responses of soybeans (G. max) and spiderwort (Tradescantia sp.) were intermediate between these two extremes. Histological observations show that lesion development results in collapsed leaf tissue in all four species. Gall formation that resulted from both cell hypertrophy and hyperplasia occurred in lesions of Tradescantia, and Q. palustris. Limited hyperplastic and hypertrophic reactions occurred in G. max foliage after exposure to simulated acid rain but no leaf galls resulted. Sporophyte foliage of P. aquilinum exhibited a “granular” type abnormality in the cytoplasm prior to the collapse of some epidermal cells injured by simulated rain. Injury occurred most frequently near vascular tissues and trichomes in all four species. In general, plant species that show cell hyperplasia and hypertrophy of leaf tissues after exposure to simulated acid rain are injured less than species that do not show these responses.     

Cyanobacteria and Cyanobacterial Lichens from Inselbergs of the Ivory Coast,Africa

This study focuses on the saxicolous lichens and cyanobacteria of the open, exposed rock surface of inselbergs. Twenty-three species of cyanobacteria and 17 cyanobacterial lichen species (“cyanolichens”) from several inselbergs and other rocky outcrops of three major climatic regions, savanna, transition zone and rain forest, are reported from the Ivory Coast. Inselbergs are isolated and frequently mountains consisting of Precambrian granites or gneisses that abruptly rise from the surrounding plains. Cyanobacteria were found to be the dominating organisms on all rock surfaces. The lichens found mainly belong to the family Peltulaceae and a few were present from the family Lichinaceae. Nine species of the cyanolichens and most of the cyanobacteria are new for the Ivory Coast. A gradient in total species number (cyanolichens and cyanobacteria) occurs from the savanna to the rain forest, with a decrease in species number towards the rain forest. Saxicolous cyanobacterial lichens reached a higher species number in the savanna type ecosystem (11) than on inselbergs in the rain forest (7). The cyanolichens and cyanobacteria found are characteristic for larger, light-exposed rock surfaces and species like P. congregate, P. lingulata, P. tortuosa and P. umbilicata preferentially occur on the granite or sandstone of inselbergs.     

中国新疆天山中东部新记录地衣种类(英文)

文中对采自乌鲁木齐市郊区和南山小渠子多个生境中的大量标本进行了外部形态与内部解剖特征观察,并对少数标本采用了显色反应法(CT)、显微化学结晶法(MCT)及薄层色谱法(TLC)等方法进行了物种鉴定。结果表明:该地区分布的地衣种类有100多种,其中包括1个中国新记录种———副茶渍属(Lecania tonin-ioides),2个新疆新记录种———美国大孢蜈蚣衣(Physconia americana)和细裂岛衣(Cetraria delisei)。副茶渍属的主要特征是鳞状地衣体边缘粉色,子囊长棍棒状,常生长在地面上;美国大孢蜈蚣衣的主要特征是小裂片旺生在子囊盘边缘和地衣体成熟的部分;细裂岛衣的主要特征是子囊棍棒状,髓层C+粉红色,含三苔色酸。文中对这些种类进行了简略描述。