Studies in the lichen family Collemataceae VII. Two new tropical Collema species

Two new Collema species are described, C. chimbuense from Papua New Guinea and C. scabrum from Ecuador, both with interesting morphological characters.     

胶衣属地衣的新分类群

本文描述了产于我国四川的胶衣属 (Collema) 两个新分类群:四川胶衣 (Collema sichuanense) 与短柄胶衣贡嘎山变种 (Collema substipitatum var. gonggashanense)。文中除了拉丁文特征提要以及英文描述以外,还附有新分类群的外形照片与孢子形态线条图。     

中国宁夏六盘山的地卷目地衣(英文)

从宁夏六盘山区的多个生境中采集了隶属于地卷目(Peltigerales)3科5属的16种地衣,分别为环纹瓦衣(Coccocarpia erythroxyli)、球胶衣(Collema coccophorum)、坚韧胶衣珊瑚变种(C.tenaxvar.corallinum)、砖孢胶衣(C.subconveniens)、亚石胶衣(C.subflaccidum)、亚洲猫耳衣(Leptogiumasiaticum)、伯尔特猫耳衣(L.burneti-i)、猫耳衣(L.menziesii)、土星猫耳衣(L.saturninum)、犬地卷(Peltigera canina)、平盘软地卷(P.elisabethae)、多指地卷(P.polydactylon)、裂芽地卷(P.praetextata)、地卷(P.rufescens)、双孢散盘衣(Solorina bispora)和凹散盘衣(S.saccata)。其中,亚洲猫耳衣和伯尔特猫耳衣为中国北方新分布种,球胶衣为中国西北新分布种,其余13种均为宁夏新记录种。地卷目地衣在六盘山区分布稀少,且表现出对较为阴湿生境的偏好。     

Microclimate and Propagule Availability are Equally Important for Rehabilitation of Dryland N-Fixing Lichens

In some arid regions, rehabilitation of whole system N-fixation may be strongly facilitated by the recovery of populations of the lichen genus Collema . Identification of the limits to recovery of Collema in apparently suitable habitat should inform selection of rehabilitation techniques. We simultaneously tested the relative importance of three hypothetical limits to Collema recovery: active erosion, resource limitation, and propagule scarcity. We found that in our experimental system, active erosion had no effect on short-term establishment of Collema, whereas propagule addition did enhance recovery and microhabitat (a resource availability gradient) also exerted a strong influence. It is possible that attempts to improve N cycling via re-establishment of Collema might be best served by developing economical means of simulating moister, cooler microhabitats, e.g., sloping soil or creating partial shade, which would favor the establishment of naturally dispersed propagules, rather than introducing propagules.     

Studies in the lichen family Collemataceae VI. Collema subundulatum, a new species from New Zealand

Collema subundulatum from New Zealand is described. It is closely related to C. undulatum , a species widely distributed in the Northern Hemisphere. It is phytogeographically somewhat similar to C. novozelandicum which is here recorded from Australia, its first known locality outside New Zealand.     

The role of water lichens in the biogeochemical processes in the Lake Baikal stony littoral

Water crustose lichens of g. Verrucaria (V. scabra Vězda, V. rheitrophyla Zsch., V. maura Wahlenb. in Ach., and V. hydrela Ach.) and water foliose lichen Collema ramenskii Elenk. were studied in the stony littoral of the western coast of Lake Baikal in 2002–2006. Their densities were highest at depths of 1.5 to 2 m; 95–100% of rock fragments collected from the depths of 1.5–2.2 m were covered by plentiful crustose thalli of Verrucaria spp. Lichens make a large contribute to the destruction of the stony ground in the shallow-water zone. Unlike water, foliose and crustose lichens concentrate Ti, La, Ce, Y, Mn, and Th. Thalli of Collema ramenskii differ from Verrucaria species in their ability to accumulate Zn, Co, and Ni. Compared to the bottom sediments, all the studied water lichen species concentrate Zn, while Collema ramenskiiconcentrate Zn and Mo.     

A new UV-B absorbing mycosporine with photo protective activity from the lichenized ascomycete Collema cristatum.

A novel photo protective mycosporine was isolated from the lichenized ascomycete Collema cristatum. Biological activity was measured in terms of protection against UV-B induced membrane destruction and pyrimidine dimer formation in cultured human keratinocytes, and prevention of UV-B induced erythema. It was found that the pure isolated compound prevented UV-B induced cell destruction in a dose-dependent manner, that the compound partially prevented pyrimidine dimer formation and completely prevented UV-B induced erythema when applied to the skin prior to irradiation.     

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.     

十二种地卷目地衣固氮活性的种间差异

地卷目地衣是对许多生态系统的氮素循环具有重要影响的固氮类群,但其固氮活性的种间差异研究甚少。将不同产地和不同馆藏时间的12种地卷目地衣于相同条件下培养,即：亚石胶衣Collema subflaccidum、亚黑胶衣C. subnigrescens、坚韧胶衣C. tenax、裸果猫耳衣Leptogium hildenbrandii、猫耳衣L. menziesii、柄猫耳衣L. pedicellatum、土星猫耳衣L. saturninum、黑猫耳衣L. trichophorum、犬地卷Peltigera canina、分指地卷P. didactyla、裂芽地卷P. praetextata和地卷P. rufescens。以乙炔还原法（acetylene reduction assay）于培养1d、10d和15d测定其固氮活性,结果显示所有地衣的固氮活性在培养10d与15d之间差异不显著,表明经过至多10d的培养后地衣固氮活性即可完全恢复;培养10d和15d的固氮活性平均值表现出显著的种间差异（P＜0.001）：黑猫耳衣Leptogium trichophorum固氮活性最高[（4.532±0.368）μmol C2H4/gdw·h],约为犬地卷Peltigera canina的2倍[（2.349±0.223）μmol C2H4/gdw·h];其他10种地衣固氮活性大致相近。显示地衣固氮作用的可塑性较大,是地衣具有较强适应能力的又一例证。     

Ultraviolet-absorbing scytonemin and mycosporine-like amino acid derivatives in exposed, rock-inhabiting cyanobacterial lichens

 The occurrence of ultraviolet (UV)-absorbing substances like scytonemin and mycosporine-glycine is reported for the first time from cyanobacterial lichens of the genera Collema, Gonohymenia and Peltula, all coming from high-light-intensity habitats. Except for Collema with the filamentous Nostoc, all other cyanobionts belong to the unicellular genera Chroococcidiopsis, Cyanosarcina, Gloeocapsa or Myxosarcina. From transmission electron microscope studies it is evident that the pigmentation (scytonemin) is located extracellularly in the sheath of the outer thallus parts. Fluorescence microscopy and microprobe measurements clearly show UV radiation into the lichen thallus and hence the relevance of UV sunscreens for the protection of the organism. Received: 4 March 1997 / Accepted: 20 May 1997     

Some effects of humidity on the light reaction of photosynthesis in the lichens Cladonia impexa and Collema flaccidium

Luminescence and fluorescence were measured at different relative humidities in the lichen Cladonia impexa Harm. Both parameters showed a constant value at relative humidities lower than 80%: thereafter they increased. Low relative humidity was found to decrease energy transfer from chlorophyll b to chlorophyll a. inhibit electron transport, lower electron holding capacity on the reduced side of photosystem two and impair far-red-induced afterglow, reflecting photophosphorylation. In Collema flaccidium Ach. Ach. energy transfer from the accessory pigments phycocyanin and phycoerythrin to chlorophyll a was only possible at high relative humidity. The results are interpreted as due to conformational changes caused by changed water content in the lichen.     

Weitere Untersuchungen zur Frage des Zusammenlebens von Pilz und Alge in den Flechten

Zusammenfassung Es wird eine neue Pyrenopsidacee,Pyrenopsis melaena, beschrieben, die intrazelluläre Haustorien der gleichen Ausbildung und Wirkungsweise wie die meisten daraufhin untersuchten Pyrenopsidaceen besitzt.An das bekannte Verhalten der Pyrenopsidaceen mit obligaten, intrazellulären Haustorien schließt sich auchAnema moedlingense an.So wie bei einem früher von mir untersuchtenCollema sp., aber im Gegensatz zu allen früheren Angaben, werden auch beiCollema aggregatum im Herbste Pilzhyphen, die ähnlich wie Haustorien wirken, zu den Algenprotoplasten entsendet.     

THE EFFECTS OF SO2 ON PHOTOSYNTHESIS AND CARBOHYDRATE TRANSFER IN THE TWO LICHENS: COLLEMA POLYCARPON AND PARMELIA CHLOROCHROA

Exposure of Parmelia chlorochroa and Collema polycarpon to 1 and 2 ppm gaseous SO₂ (4-, 8-, and 12-hr fumigations) initially stimulated photosynthesis but prolonged exposure depressed it. Carbohydrate transfer decreased in both species but increased significantly after a 12-hr exposure in C. polycarpon. Interference with normal oxidation-reduction and denaturation of enzymes and membrane proteins by sulfite and bisulfite ions may account for the observed results. Increased conductivity of leachates reflected SO₂-induced damage at both 1 and 2 ppm sO₂.     

Further notes on European taxa of the lichen genus Leptogium,with emphasis on the small species

Abstract:Leptogium imbricatum P.M. Jørg. sp. nov. and L. intermedium (Arnold) Arnold are established as the correct names for two fairly widespread, small species: L. imbricatum has an arctic-alpine distribution. Leptogium intermedium was previously mostly named L. minutissimum (Flörke) Fr., the type of which is L. subtile (Schrader) Torss., a distinct species usually growing on rotting wood or debris. Leptogium magnussonii Degel. & P.M. Jørg, mainly from maritime rock outcrops in Norway and Sweden, is described as new. The species complexes of L. plicatile (Ach.) Leighton and L. schraderi (Bernh.) Nyl. are discussed. The differences between L. byssinum (Hoffm.) Nyl. and L. biatorinum (Nyl.) Leighton are given, and L. aquale (Arnold) P.M. Jørg. comb. nov., a taxon related to the latter, is considered to be a distinct species growing in mountain brooks in Central Europe. Leptogium rivale Tuck. is recorded as new to Europe, from Romania. Leptogium bellopratense Hy is shown to be a synonym of L. brebissonii Mont. New records for L. coralloideum (Meyen & Flotow) Vainio, L. massiliense Nyl and L. rivulare (Ach.) Mont. are given. A preliminary key to the small European species (north of the Alps) is appended. The following names have been lecto- or neotypified: Collema byssinum Hoffm., Collema pulvinatum Hoffm., Leptogium bellopratense Hy., Leptogium crenulatum Watson, Leptogium massiliense Nyl., Leptogium minutissimum var. intermedium Arnold, Leptogium minutissimum f. plumbeum Zwackh ex Arnold, Leptogium pusillum var. aquale Arnold, Leptogium rivulare var. crenatulum Nyl., Leptogium scotinum var. crenatum Nyl., Lichen byssinus Hoffm., Lichen minutissimus Flörke, Lichen schraderi Bemh., Lichen subtilis Schrader and Parmelia scotina var. lophaea Ach.     

An Examination of some Symbiotic Systems for Fixation of Nitrogen

By the use of ¹⁵N the occurrence of fixation of elemental nitrogenhas been demonstrated in the lichens Collema granosum and Leptogiumlichenoides (both of which contain Nostoc as a symbiont), andalso in the liverwort Blasia pusilla (which has Nostoc-containingcavities in the thallus). The circumstances indicate that thefixation in these instances should be attributed to the Nostoc. No evidence of fixation was obtained in similar isotopic testson the mycorrhizal roots of intact plants of Calluna vulgarisand of Pinus sylvestris, although these, more especially inthe case of Calluna, have been held by some previous authorsto be nitrogen-fixing.     

Original data on the diversity,ecology, and chemical composition of aquatic and semiaquatic lichens (Lichenes) of the stony littoral of Lake Baikal

Data on semiaquatic epilithic and aquatic lichens predominant in the surf and littoral zones of the test site Cape Berezovyi (Southern Baikal) obtained in 2002–2005 are presented. This is the first report on the distribution of rare and unfamiliar aquatic lichen species, Collema ramenskii Elenk. and Verrucaria spp. on the stony littoral of the western Baikal shore. The lichens form dense aggregations at depths from 1–1.5 to 3–3.5 m, where Verrucaria spp. thalli densely cover 60–70% of the rock debris. Only occasional lichens are observed below 7 m. Features of the penetration of aquatic Verrucaria spp. thalli into the rock debris were examined by electron microscopy. The chemical composition of aquatic lichens was analyzed for the first time. It was shown that aquatic lichens are capable of accumulating Ti, Ga, Y, and rare earths poorly soluble in the water of the stony littoral. The original data point to the active role of aquatic lichens in biogeochemical destruction of rocks of the Baikal stony littoral.     

新疆博格达山岩面生地衣群落结构特征

根据对新疆博格达山岩面生地衣群落20个样点(20m×20m)调查的数据,以各地衣种的盖度为指标结合双向指示种分析方法(TWINSPAN)和除趋势对应分析法(DCA)对博格达山岩面生地衣群落进行数量分类并分析了群落结构特征及其多样性和相似性。采用典范对应分析法(CCA)对各群落的物种分布格局与环境因子的关系进行研究。结果表明,TWINSPAN分析和DCA排序将分布在博格达山的37种岩面生地衣分为以下5个群丛。群丛1:斑纹网衣(Lecidea tessellate Florke)+粉芽盾衣(Peltula euploca(Ach.)Poelt)+杜瑞氏黄梅(Xanthoparmelia durietzii Hale)群丛,有25个种,总覆盖度为30.145%,多样性为4.025;群丛2:袋衣(Hypogymnia physodes(L.)Nyl.)+白边平茶渍(Aspicilia sublaqueata(H.Magn.)J.C.Wei)+砖孢胶衣(Collema subconveniens Nyl.)群丛,有17个种,地衣总盖度为15.885%,多样性为3.196;群丛3:聚茶渍(Lecanora accumulate H.Magn.)+丽石黄衣(Xanthoria elegans(Link)Th.Fr.)+亚洲平茶渍(Aspicilia asiatica(H.Magn.)Yoshim.)群丛,有30个种,地衣总盖度为37.87%,多样性为4.357;群丛4:中华石果衣(Endocarpon sinense H.Magn.)+伴藓大孢蜈蚣衣(Physconia muscigena(Ach.)Poelt.)+垫脐鳞衣(Rhizoplaca melanophthalma(DC.)LeuckertPoelt)群丛,有24个种,地衣总盖度为30.458%,多样性为3.912;群丛5:石胶衣(Collema flaccidum(Ach.)Ach.)+短绒皮果衣(Dermatocarpon vellereum Zschacke)+绿黑地图衣(Rhizocarpon viridiatrum(Wulfen)Korber.)群丛,有18个种,地衣总盖度为19.331%,多样性为3.515。CCA排序结果反映,该地区岩面生地衣的分布与海拔高度、光照强度、岩石pH和人为干扰有关,其中影响最大的因素是海拔高度,其次为光照强度和干扰。坡向和岩石大小对地衣种类分布的影响不显著。     

不同水分条件下坚韧胶衣固氮活性对冻融的响应

坚韧胶衣Collema tenax是干旱和半干旱生态系统中生物土壤结皮的重要组分,其固氮作用对生态系统氮素循环具有重要影响。该地衣生长于温度和水分条件变化剧烈的土壤表面,但在我国北方其固氮活性对冻融的响应尚不清楚。采用乙炔还原法研究了坚韧胶衣固氮活性在不同水分条件下(湿冻组:地衣体含水量200%干重;干冻组:地衣体含水量20%干重)和4次冻融处理之间的差异。坚韧胶衣固氮活性为2,371.0-8,701.8nmolC2H4/m2·h,湿冻组固氮活性低于干冻组,对照组固氮活性最高,湿冻组和干冻组的固氮活性(对照的百分比)均与冻融次数呈显著的线性负相关关系(干冻组:R2=0.916,p0.001;湿冻组:R2=0.965,p0.001),但湿冻组的斜率绝对值(25.05)明显高于干冻组斜率绝对值(7.60)。结果表明低温对坚韧胶衣固氮活性具有显著抑制作用,干燥条件下坚韧胶衣固氮活性对于低温胁迫的敏感性比地衣体湿润条件下更低,这种较低的敏感性可能是该地衣对我国北方干燥和冷热变化剧烈的气候特点的生理适应策略。     

Nocturnal respiration of lichens in their natural habitat is not affected by preceding diurnal net photosynthesis

Dark respiration (DR) of lichens is reported to be higher in species with a high photosynthetic potential (suggesting a metabolic maintenance cost effect) and also, often in laboratory studies, transiently after photosynthesis (suggesting a substrate-driven effect). We investigated the occurrence of the latter, the effect of diurnal net photosynthesis (NP) on subsequent nocturnal DR, under natural temperate climate conditions in the chlorolichens Lecanora muralis and Cladonia convoluta and the cyanolichen Collema cristatum. Data sets totalling 15 months, 106 and 113 days, respectively, were obtained from automatic cuvettes that continually measured CO₂ exchange and ambient conditions at 30 min intervals. For each 24 h period (sunrise to following sunrise), several measures of NP and DR were extracted, including maximal and mean rates and daily sums. No statistically significant correlations between the various measures of DR and preceding NP were found for L. muralis, only one weak correlation for Co. cristatum (the means of DR and NP) and three for Cl. convoluta (sums and means of DR and NP). It is proposed that even these significant correlations are actually a result of embedded codependencies between NP, DR and thallus water content. Overall it is concluded that no substrate-driven dependency of DR on preceding NP under natural conditions could be recognised. The periods of desiccation that often occur between the NP and following DR as well as the wide range of combinations of conditions would certainly contribute to this lack of relationship.     

Spatial distribution of epiphytes on Populus tremula in relation to dispersal mode

Abstract. We examined if the spatial distribution of epiphytes in a forest stand differs between two sexually and three asexually dispersed species. As study species we have chosen two sexually dispersed species, the lichen Collema curtisporum and the bryophyte Orthotrichum speciosum, and three asexually dispersed species, the lichens C. furfuraceum and Leptogium saturninum and the bryophyte O. obtusifolium. All of these species grow on Populus tremula. In P. tremula stands, individual trees may be regarded as distinct patches for the studied species, while the stand represents a “landscape” of discrete patches. The study was performed in two relatively homogeneous forest stands. The study revealed that the asexually dispersed species were more common than the sexually dispersed. It was also shown that the sexually dispersed species were more aggregated than P. tremula in both stands. In contrast, the distribution of the asexually dispersed species mirrors, more or less, the distribution of their host, i.e. the spatial pattern shown by P. tremula. It is unlikely that the measured environmental variables strongly influenced the observed spatial distribution. Thus, we suggest that the different dispersal and establishment strategies were important in shaping the local distribution of the species.