地衣对放射性核素的吸收与积累及其在环境监测中的应用

阐述了地衣对放射性核素的吸收与积累及环境因子的影响;讨论了地衣在环境放射性监测中的应用及存在问题。同时,介绍了一个地衣吸收放射性核素的动态模型,以简化监测结果的分析。     

中国蜈蚣衣科地衣多样性及区系研究

该研究通过对山西管涔山和五鹿山等区域采集的蜈蚣衣科地衣300余份标本的鉴定分析,结合已有报道,从物种多样性、空间分布特点、生境类型及区系成分等方面对蜈蚣衣科地衣进行研究,以明确中国蜈蚣衣科地衣物种组成及区系特点。结果表明：(1)中国蜈蚣衣科地衣共有7属197种54变种,饼干衣属(Rinodina)占绝对优势,约占蜈蚣衣科地衣总种数的30.5%。(2)中国蜈蚣衣科地衣多分布于新疆,蜈蚣衣属(Physcia)是该科中分布最广泛的属,但其中有26.4%的物种仅分布于单一地区。(3)蜈蚣衣科地衣生境类型多样,有树生、石生、藓丛生、土生和多生境5种,以多生境地衣为主(48.5%)。(4)中国蜈蚣衣科地衣的地理成分复杂,同时伴随多种区系成分,但以温带性质显著(占43.1%),东亚特色明显。(5)仅分布于中国的蜈蚣衣科地衣共4属10种,且主要分布于中国东北、西北和西南地区。     

新疆天山大峡谷地衣的地理成分及其生态特征分析

对新疆天山大峡谷地衣进行调查研究,查阅相关资料,初步对该地区地衣进行分类和整理。结果表明：该区地衣有81种,隶属5目,15科,26属,其中地卷属,石蕊属和蜈蚣衣属种类最多,分别占14.81%,12.35%和9.87%。我们将新疆天山大峡谷地理区系划分为世界广布区、环北极广布区、欧亚-北美分布区、环北极-高山分布区、环北方分布区、欧亚-北非分布区、地中海-西亚和中亚分布区、北温带分布区和中国特有等9种类型。研究还发现该地区岩树枝及树皮生地衣与朽木生地衣占主导地位。     

新疆准噶尔盆地南缘土壤生物结皮中地衣物种组成和分布

对新疆准噶尔盆地沙漠南缘土壤生物结皮中地衣种类及分布特征进行了初步研究。结果表明,该地区参与土壤生物结皮的有藓生双缘衣（Diploschistes muscorum（Schreb．）Norm．]、拟橙衣（Fulgensia bracteata（Hoffm．）Raws．]、丽石黄衣[Xanthoria elegans（Link）Th．Fr]、准噶尔橙衣（Caloplaca songoricumA．Abbas）和磷网衣[Psora decipiens（Ehrh．）Hoffm．]等13种地衣,分别属于5目10科。对其分布特征进行了分析,发现地衣的分布与苔藓有相关性;地衣的分布受到环境温度、太阳辐射强度和降水量等因素的影响。聚类分析结果表明,24个样方可分为3组,分别分布于沙丘底部、顶部和中部,其中分布于沙丘底部的样方地衣种类的多样性最高。     

中国新疆博格达山周边地区大型地衣物种多样性及分布特征

本研究对中国新疆博格达山周边地区大型地衣进行地衣分类学和生态学结合的综合研究,通过分析大型地衣物种多样性和分布特征,探讨影响地衣分布的环境变量与生态因子。研究结果表明:(1)分布在博格达山周边地区的大型地衣共有43种,隶属于6目、11科、15属,其中茶渍目和黄枝衣目大型地衣占优势,分别占该地区大型地衣科、属、种总数的55%、67%、81%。(2)博格达山周边地区的大型地衣组成5个样点组,分别是蓝灰蜈蚣衣+裂片石黄衣组、细片石黄衣+亚灰大孢蜈蚣衣组、长缘毛蜈蚣衣+菊叶黄梅组、地卷+暗裂芽黑蜈蚣衣组、黑蜈蚣衣+枪石蕊组,样点组的分布与环境因子密切相关。(3)在影响大型地衣分布的环境因素中海拔对地衣种类分布的影响较显著。本研究为更准确地确定博格达山区大型地衣分布规律提供科学依据。     

荒漠地衣结皮研究进展

微型生物结皮在干旱、半干旱荒漠地区广泛分布,对维持荒漠生态系统的稳定性具有重要作用。地衣结皮是微型生物结皮的重要组成部分及主要类型之一,在固沙、固碳和固氮能力方面独具优势。本文从区域尺度和局部尺度综述了国内外荒漠地衣分布、群落组成及其影响因素,从微尺度探讨了荒漠地衣在形成过程中可能相关的生物因子的作用与功能。虽已有研究发现气候类型、降水量、土壤理化性质、微地形和温度会对荒漠地衣生长型、种类、丰度及盖度产生影响,来自地衣体、地衣结皮和地衣结皮土壤中的生物因素与维持地衣正常生命活动及分布之间存在相关关系,但上述结论尚具有一定的局限性,主要表现在区域尺度仍缺乏专门对荒漠地衣的研究,微尺度缺乏对地衣相关生物功能的实验性探索及验证。上述局限在一定程度上限制了通过人工手段大规模应用荒漠地衣结皮的研究。本文基于国内外研究进展及存在问题,对荒漠地衣结皮应用进行了展望,以期为人工构建荒漠地衣结皮和干旱、半干旱荒漠治理及生态恢复提供新的思路和参考。     

新疆石人沟山区岩面生地衣群落分布格局的环境解释

地衣作为真菌和绿藻/蓝绿藻的成功共生体,广泛分布在陆地生态中的各种栖息地。岩面生地衣作为陆地生态系统的主要组成部分,在干旱和半干旱地区陆地食物链中具有重要地位,同时对岩石的生物腐蚀和土壤的形成有重要作用。岩面生地衣的多样性和分布格局强烈地受到海拔、湿度、温度、降水量、太阳辐射强度和基物的特征(岩石类型、岩石大小、岩石的化学成分和营养成分)等多种因素的影响。为了研究乌鲁木齐县石人沟山区岩面生地衣群落与基物间的关系,该研究在乌鲁木齐县石人沟山区设立16个样地,计测样地中岩面生地衣的盖度,包括坡度、坡向、光照强度等7个环境因子,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了探讨。结果表明:石人沟山区的岩面生地衣共有27种,隶属于7目9科15属。其中,黄枝衣目、茶渍目和鸡皮衣目的种类较多,占该地区岩面生地衣总数的74.07%。CCA排序结果显示坡度、坡向、光照强度、湿度、岩石pH值是5个影响岩面生地衣种类分布格局的主要环境因子,并显示了岩面生地衣与样地间的对应性。     

哀牢山山地森林不同附生地衣功能群的水分关系和光合生理特征

附生地衣是热带和亚热带山地森林生态系统中重要的结构性组分, 在生物多样性保护、环境监测、养分循环中发挥着重要作用。附生地衣按共生藻、生活型和繁殖策略的不同可划分为不同的功能群, 不同附生地衣功能群的分布格局存在较大的差异, 然而其生理生态机制仍不清楚。该研究以我国西南地区哀牢山亚热带山地森林中的附生地衣优势类群为研究对象, 对该地区蓝藻地衣、阔叶地衣、狭叶地衣及枝状地衣4种功能群的8种附生地衣的水分关系、光合生理特征等进行了测定分析, 结果显示: 不同功能群附生地衣的持水力和失水速率均存在差异, 其中蓝藻地衣具有较高的最大水分含量, 而枝状地衣的失水速率较快; 过高和过低的水分含量都会抑制附生地衣的光合作用, 但抑制程度有所差异; 蓝藻地衣的光合作用最适水分含量比较高, 表明它们的光合生理活动对水分条件要求较高, 所以它们偏好潮湿的生境, 同时蓝藻地衣的光补偿点比较低但光饱和点却不低, 反映出它们具有较宽的光强适应范围, 所以蓝藻地衣能够同时分布于强光和弱光生境中; 枝状地衣的光合最适水分含量较低, 表明它们的光合生理活动对水分条件要求不是很高, 能够适应较为干旱的环境, 同时枝状地衣的光补偿点和光饱和点都很高, 说明它们的光合生理活动对光照条件要求比较高, 所以它们广泛分布于强光生境中; 阔叶和狭叶地衣的光补偿点比较高, 说明它们更适应有充足光照条件的生境。     

新疆大学“中国西北干旱区地衣研究中心”团队

正新疆大学"中国西北干旱区地衣研究中心"于1985年开始对中国新疆地衣研究进行系统性研究,包括新疆地衣资源调查、地衣分类学、地衣区系地理、地衣种群及群落生态学、地衣分子系统学研究,地衣组织培养和地衣有效成分分析等研究领域。其中,地衣系统分类学、地衣生态学、地理区系分布特征、地衣及其分类培养共生藻的重金属耐性和机制等方面的研究比较多。团队共有5名教师、博士学历4名,其中教授2名、副教授2名、讲师1名,在岗的师生当中有汉族、回族、维吾尔族、哈萨克族、柯尔克孜族、塔塔尔族等多个民族,是一个团结、和谐、具有高学历和职称的团队。     

中国砖孢发属地衣研究

简短回顾了砖孢发属地衣研究概况。在已知的8种亚洲砖孢发属地衣中,中国有七种,其中两种为台湾特有。根据150余份标本的形态与化学特征,承认中国大陆砖孢发属地衣5种,指出了个别异名,发现亚洲砖孢发(Okpogon asiaticus)存在两个化学型,提供了中国5种砖孢发地衣分布的新资料。研究结果表明,5种砖孢发地衣集中分布于我国云南、四川和西藏东部。作者认为中国西南地区是砖孢发属地衣在亚洲的一个分布中心。     

东北大小兴安岭地区梅衣科岛衣类和袋衣类地衣物种多样性

东北大小兴安岭地区是中国地衣的重要分布地之一, 蕴藏着丰富的地衣生物多样性。本研究基于259份标本馆馆藏及采集自东北大小兴安岭31个保护区的新鲜地衣标本, 结合形态学、解剖学、化学和DNA片段的综合分析, 鉴定并报道了该地区梅衣科岛衣类和袋衣类地衣11属31种, 包括环北极成分13种, 东亚成分11种, 世界广布成分3种, 中国特有成分3种, 欧亚成分1种。与之前记录和报道的该地区同类地衣物种组成进行对比, 结果显示隶属于2属的6种地衣在该地区未被重新发现, 表明这些地衣在该地区的分布可能大大萎缩乃至消失, 尤其是属于东亚成分的袋衣属2种: 粉袋衣(Hypogymnia farinacea)和日光山袋衣(H. nikkoensis), 自最初以东北大小兴安岭标本为凭证在中国报道分布后, 30余年未再新增任何标本信息, 日光山袋衣在近期中国大型真菌红色名录评估中被推测处于易危状态。     

Non-dominant trees significantly enhance species richness of epiphytic lichens in subtropical forests of southwest China

Host species has an important influence on the distribution of epiphytic lichens in forests. However, the importance of non-dominant trees in shaping lichen communities has been poorly studied owing to the relative rarity of individuals. The importance of dominant and non-dominant trees for distribution of epiphytic lichens was determined in eight subtropical forests in southwestern China. Dominant trees supported more abundant total and exclusive lichen species only in secondary forests. The occurrence of non-dominant trees promoted lichen diversity within forest types and influenced lichen communities on both tree groups. The effects of total tree species on lichen distribution largely resulted from the presence of non-dominant trees. Dominant and non-dominant trees supported distinct lichen assemblages within forest types, and ordination analyses showed a clear separation. Our study, therefore, reinforces the importance of non-dominant trees for conserving epiphytic lichens, and highlights that lichen assemblages are shaped by both dominant and non-dominant trees.     

Radioisotope stents for the prevention of restenosis: what did we learn from pre-clinical studies?

This article will discuss the lessons learned by using stents implanted with low activities of radioisotopes to prevent in-stent restenosis. A continuous low-dose rate radiation delivered by radioisotope stents has been shown to reduce the proliferative activity of smooth muscle cells and to inhibit neointimal growth. However, the radiation also delays endothelialization of the stents. Both the dose rate and the cumulative dose delivered by radioisotope stents appear to affect outcome. The neointima covering radioactive stents is characterized by a reduced cellularity, increased amounts of fibrin and extracellular matrix proteins. Aneurysm formation or excessive tissue destruction due to the radiation were not observed. Animals studies including up to 1 year follow-up periods suggest that beta-particle-radiation as well as gamma-radiation are effective in reducing neointimal hyperplasia. It is still unknown, however, which range of activities are needed and if a combination of radioisotopes, i.e. with short and long halflives, further reduce neotima formation over the long-term. An appropriate stent design for homogenous dose distribution around the stent may be important, i.e. articulations or large cell sizes may have disadvantages. Augmented neointima formation at the ends of radioactive stents, in particular when using beta-particle emitting stents, has been observed in animal models. Future studies will focus on the effects of increasing activity levels at the stent ends, optimal stent designs, alternative isotopes and different dosing strategies.     

新疆北部松萝属地衣生态分布与地理区系成分分析

根据多年的实地调查资料和前人研究资料,对新疆北部松萝属地衣的种类以及它们的分布区、区系特征和垂直分布进行了初步研究。结果表明,分布在新疆北部的松萝属地衣共有22种,主要分布在天山和阿勒泰山,生长在树皮、树枝和朽木上。根据它们对环境的适应特征和选择性,将新疆北部松萝属地衣的主要地理成分分为环极北极及北方成分、北美-欧洲成分、世界广布种、北美成分、环极低北极及北方成分、欧洲成分、东亚—北美成分等7种。研究还发现分布在阿勒泰山和天山的松萝属地衣的垂直分布有明显的差异。阿勒泰山的地衣分布海拔比较高,分布范围比较广泛。     

Major clades of parmelioid lichens (Parmeliaceae, Ascomycota) and the evolution of their morphological and chemical diversity

Parmelioid lichens comprise about 1500 species and have a worldwide distribution. Numerous species are widely distributed and well known, including important bioindicators for atmospheric pollution. The phylogeny and classification of parmelioid lichens has been a matter of debate for several decades. Previous studies using molecular data have helped to establish hypotheses of the phylogeny of certain clades within this group. In this study, we infer the phylogeny of major clades of parmelioid lichens using DNA sequence data from two nuclear loci and one mitochondrial locus from 145 specimens (117 species) that represent the morphological and chemical diversity in these taxa. Parmelioid lichens are not monophyletic; however, a core group is strongly supported as monophyletic, excluding Arctoparmelia and Melanelia s. str., and including Parmeliopsis and Parmelaria. Within this group, seven well-supported clades are found, but the relationships among them remain unresolved. Stochastic mapping on a MC/MCMC tree sampling was employed to infer the evolution of two morphological and two chemical traits believed to be important for the evolutionary success of these lichens, and have also been used as major characters for classification. The results suggest that these characters have been gained and lost multiple times during the diversification of parmelioid lichens.     

新疆平茶渍属地衣生态分布与地理区系成分分析

根据多年的实地调查资料和前人研究资料,对新疆平茶渍属（Aspicilia）地衣的种类以及它们的分布区、区系特征进行了初步研究。结果表明,分布在新疆的平茶渍属地衣共有33种,主要分布在天山、阿勒泰山、昆仑山和准噶尔盆地。根据它们对环境的适应特征和选择性,将新疆平茶渍属地衣的地理区系划分为广布种、环极北极高山种、环极低北极及北方种、北美东部种、中亚种、中国特有种、分布范围不清楚的种等7种类型。同时把新疆平茶渍属地衣的地理分布区域划分为欧亚森林植物亚区、亚洲荒漠植物亚区、青藏高原亚区等三种分布区域。研究还发现分布在阿勒泰山、天山、昆仑山和准噶尔盆地的平茶渍属主要生长在岩石上面,生长基物比较单一。     

Transoceanic dispersal and subsequent diversification on separate continents shaped diversity of the Xanthoparmelia pulla group (Ascomycota)

In traditional morphology-based concepts many species of lichenized fungi have world-wide distributions. Molecular data have revolutionized the species delimitation in lichens and have demonstrated that we underestimated the diversity of these organisms. The aim of this study is to explore the phylogeography and the evolutionary patterns of the Xanthoparmelia pulla group, a widespread group of one of largest genera of macrolichens. We used a dated phylogeny based on nuITS and nuLSU rDNA sequences and performed an ancestral range reconstruction to understand the processes and explain their current distribution, dating the divergence of the major lineages in the group. An inferred age of radiation of parmelioid lichens and the age of a Parmelia fossil were used as the calibration points for the phylogeny. The results show that many species of the X. pulla group as currently delimited are polyphyletic and five major lineages correlate with their geographical distribution and the biosynthetic pathways of secondary metabolites. South Africa is the area where the X. pulla group radiated during the Miocene times, and currently is the region with the highest genetic, morphological and chemical diversity. From this center of radiation the different lineages migrated by long-distance dispersal to others areas, where secondary radiations developed. The ancestral range reconstruction also detected that a secondary lineage migrated from Australia to South America via long-distance dispersal and subsequent continental radiation.     

Hierarchical analysis of the relationship between spatial distribution and abundance of epiphytic lichens (Mt. Olympos-Greece)

The relationship between distribution and abundance of epiphytic lichens on five different substrates (Fagus sylvatica, Pinus nigra, Quercus coccifera, Pinus heldreichii and Quercus pubescens) has been studied. For the first three substrates the above relationship has been studied hierarchically. It was concluded that this relationship is partly represented by the core-satellite distribution. This abundance-distribution pattern could probably be explained by more than one hypothesis and it is probably related with the life strategies of lichen species.     

太白山药用地衣的种质资源及其化学成分的研究概况

地衣是低等植物的重要类群,为菌藻共生体,全世界已知有500多属26 000余种,中国有232属1 766种.我国历代本草记载药用地衣约200种,著名的有石蕊、松萝等,秦岭太白山有药用地衣37种,其中常用13种.其主要成分为地衣多糖和地衣酸,具有抗肿瘤、抗辐射及抗菌等生物活性,太白山药用地衣是陕西民间中草药的重要组成部分,具有一定的开发应用潜力.