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 vat．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。     

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。     

火烧对内蒙古草原中坚韧胶衣固氮活性的影响

 坚韧胶衣(Collema tenax)是干旱和半干旱草原中常见的一种固氮地衣, 是草原生态系统中生物土壤结皮(Biological soil crust)的 主要组成部分, 对生态系统氮循环具有重要的影响。火烧作为一种干扰因子, 是草原生态系统结构和功能维持的重要因素之一。该文采用乙炔 还原法(Acetylene reduction assay), 研究了火烧对内蒙古草原生态系统中坚韧胶衣固氮活性的短期影响。结果表明, 在个体尺度上, 与对照 相比, 火烧区中地衣体烧损的坚韧胶衣固氮活性降低了42.3%, 而无烧损的个体固氮活性则升高了28.4%。这表明火烧对坚韧胶衣的固氮功能在 个体尺度上具有双重影响: 1)通过烧损地衣体、恶化地表温度和水分条件, 而抑制个体的固氮活性; 2)通过改善光照条件, 使表土养分呈现脉 冲式增高, 而促进未烧损个体的固氮活性。在种群尺度上, 火烧与对照之间固氮活性并无显著差异, 这可能是由于火烧在个体尺度上对坚韧胶 衣的固氮活性的双重影响相互抵消所致。     

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。     

干旱持续时间对内蒙古草原中坚韧胶衣和分指地卷固氮活性的影响

坚韧胶衣Collema tenax和分指地卷Peltigera didactyla是分布于我国北方干旱和半干旱草原中的两种固氮地衣,对生态系统氮素循环具有重要影响,其生理活性对土壤水分条件比较敏感。目前,干旱持续时间对该区域中地衣固氮活性的影响尚不清楚。本文调查了一个克氏针茅Stipa krylovii草原生态系统中坚韧胶衣和分指地卷的盖度,采用乙炔还原法研究了不同干旱持续时间(分别为0、1、2、4、8和16d)对两种地衣固氮活性的影响。结果表明,坚韧胶衣盖度(3.26±1.24%)显著高于分指地卷(0.02±0.07%)(p<0.01);在绝大多数干旱持续时间处理下,两种地衣之间的固氮活性差异并不显著,且均随干旱持续时间延长而呈S形下降。不超过2d的干旱时间并不引起地衣固氮活性的显著变化,4d的干旱时间导致坚韧胶衣和分指地卷固氮活性分别下降了34%和54%,干旱持续8d导致两种地衣固氮活性降幅达90%,16d的干旱使二者降幅均超过99%。表明干旱对坚韧胶衣和分指地卷固氮活性的抑制作用随干旱持续时间的延长而增强。干旱对地衣固氮作用的负效应可能与地衣体内光合产物和能量水平、复水至表达固氮活性之间的延迟时间和达到最高固氮活性的延迟时间有关。     

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。     

柔膜菌科新分类群及中国新记录种（英文）

对来自我国不同地区的柔膜菌科真菌进行了分类研究,发现3个新种(新疆绿胶杯菌、多隔拟散胞盘菌、河南新胶鼓菌)和1个新变种(落叶松芽孢盘菌小囊变种)以及3个未命名种,分别属于绿散胞盘菌属(Chlorencoelia sp.8357)、斯特罗盘菌属(Strossmayeria sp.1683)和丝绒盘菌属(Velutarina sp.4115),报道2个中国新记录种(卷边盘菌、泪滴暗被盘菌)。对上述分类群进行了详细的形态解剖学描述和图解,对新分类群与相近种的区别进行了讨论。     

云南禾草新分类群的拉丁文描述补记

《中国主要植物图说——禾本科》(以下简称“图说”)系耿以礼教授(1897—1975)主编,1959年4月出版,迄今已有22年之久了。由于该书中所有的新分类群都缺少拉丁文的内容,故在当时仅能算是非合法性发表。嗣后,约有半数的新种(及新变种等)已在其它刊物上(参见文末的附录)陆续补写了拉丁文描述,方使它们成为正式的合格发表。本文旨在用拉丁文补写该书中原产于云南的新分类群15个(计拂子茅属1新系、归     

国际真菌分类委员会为系统真菌学工作者制定的实践守则

国际真菌分类委员会建议真菌学家在真菌(包括酵母菌)的系统学研究中坚持他们提出的15点建议(原文摘要中为14点建议,文内为15点建议,故译文将摘要改为15点建议——译者注),并把它们作为工作的实践守则。采用这个守则可以促进命名上的稳定性和达到真菌描述上的一致性(本文所说的“真菌描述”都是指真菌新分类群的发表——译者注)。     

An unusual juxtaposition of polysaccharide components of Collema leptosporum

The lichenised ascomycete, Collema leptosporum Malme, was extracted with aqueous methanol to give traces of mannitol and 3-O-β- -glucopyranosyl- -mannitol (2.7% yield). The residue was consecutively extracted with hot water to give a complex uronic acid-containing polysaccharide, and then with hot aqueous alkali which provided a mixture of polysaccharides. This was fractionated with Cetavlon to give a branched galactomannan, which had the lowest content of galactose yet reported for such a lichen polysaccharide. It has a main chain of (1→6)-linked -Manp units partly substituted at O-2,4 by non-reducing end-units of Manp and Galp, shown by NMR spectroscopy to have - and β-configurations, respectively. The other polysaccharide component was unexpectedly a branched (1→3), (1→6)-linked β-glucan, which is typical of a basidiomycete, whereas those of ascomycetes contain similar linkages but in linear glucans.     

Dynamics of cover, UV-protective pigments, and quantum yield in biological soil crust communities of an undisturbed Mojave Desert shrubland

Biological soil crusts are an integral part of dryland ecosystems. We monitored the cover of lichens and mosses, cyanobacterial biomass, concentrations of UV-protective pigments in both free-living and lichenized cyanobacteria, and quantum yield in the soil lichen species Collema in an undisturbed Mojave Desert shrubland. During our sampling time, the site received historically high and low levels of precipitation, whereas temperatures were close to normal. Lichen cover, dominated by Collema tenax and C. coccophorum, and moss cover, dominated by Syntrichia caninervis, responded to both increases and decreases in precipitation. This finding for Collema spp. at a hot Mojave Desert site is in contrast to a similar study conducted at a cool desert site on the Colorado Plateau in SE Utah, USA, where Collema spp. cover dropped in response to elevated temperatures, but did not respond to changes in rainfall. The concentrations of UV-protective pigments in free-living cyanobacteria at the Mojave Desert site were also strongly and positively related to rainfall received between sampling times (R² values ranged from 0.78 to 0.99). However, pigment levels in the lichenized cyanobacteria showed little correlation with rainfall. Quantum yield in Collema spp. was closely correlated with rainfall. Climate models in this region predict a 3.5–4.0 °C rise in temperature and a 15–20% decline in winter precipitation by 2099. Based on our data, this rise in temperature is unlikely to have a strong effect on the dominant species of the soil crusts. However, the predicted drop in precipitation will likely lead to a decrease in soil lichen and moss cover, and high stress or mortality in soil cyanobacteria as levels of UV-protective pigments decline. In addition, surface-disturbing activities (e.g., recreation, military activities, fire) are rapidly increasing in the Mojave Desert, and these disturbances quickly remove soil lichens and mosses. These stresses combined are likely to lead to shifts in species composition and the local extirpation of some lichen or moss species. As these organisms are critical components of nutrient cycling, soil fertility, and soil stability, such changes are likely to reverberate throughout these ecosystems.     

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.     

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.     

Distribution of N,P, K,Ca, Mg,S, Zn,Fe, Mn and Cu in groundnut

Summary Concentration of N, P, K, Ca, Mg and S in summer groundnut crop was higher than in kharif while Zn, Fe, Mn and Cu contents were higher in summer crop. Kernel's N, P and Zn; Leaflet's Ca and Mn; Stem's K and Fe; Root's S and Cu and Petiole's Mg contents were highest. Shell's N, P, K, Mg, S, Zn and Cu; Kernel's Ca, Fe and Mn contents were the least. N, P, K, S, Zn and Cu concentrations decreased linearly as the crop grew. Ca, Mg, Fe and Mn concentrations did not display any distinct pattern. Ca concentration was positively correlated with pod yield in both the seasons.     

Extracellular Adenosine, Inosine, Hypoxanthine, and Xanthine in Relation to Tissue Nucleotides and Purines in Rat Striatum During Transient Ischemia

Extracellular (EC) adenosine, hypoxanthine, xanthine, and inosine concentrations were monitored in vivo in the striatum during steady state, 15 min of complete brain ischemia, and 4 h of reflow and compared with purine and nucleotide levels in the tissue. Ischemia was induced by three-vessel occlusion combined with hypotension (50 mm Hg) in male Sprague-Dawley rats. EC purines were sampled by microdialysis, and tissue adenine nucleotides and purine catabolites were extracted from the in situ frozen brain at the end of the experiment. ATP, ADP, and AMP were analyzed with enzymatic fluorometric techniques, and adenosine, hypoxanthine, xanthine, and inosine with a modified HPLC system. Ischemia depleted tissue ATP, whereas AMP, adenosine, hypoxanthine, and inosine accumulated. In parallel, adenosine, hypoxanthine, and inosine levels increased in the EC compartment. Adenosine reached an EC concentration of 40 microM after 15 min of ischemia. Levels of tissue nucleotides and purines normalized on reflow. However, xanthine levels increased transiently (sevenfold). In the EC compartment, adenosine, inosine, and hypoxanthine contents normalized slowly on reflow, whereas the xanthine content increased. The high EC levels of adenosine during ischemia may turn off spontaneous neuronal firing, counteract excitotoxicity, and inhibit ischemic calcium uptake, thereby exerting neuroprotective effects.     

Neutrino intergalactic communication,metal life,and viruses: Part 1 quo vadis ex machina

At one spectrum extreme, Astrobiology conjectures that for exoplanets with Goldilocks conditions, terrestrial-like life is inevitable. Moreover, it is envisaged that via panspermia, terrestrial-like life and its precursors are transferred among galaxies, stars, and within solar systems via transiting comets, asteroids, and planetoids. In addition, expelled stars, which have solar systems, it is inferred, transfer life as well. However, at the other extreme, we propose a paradigm shift that on some planets, subject to non- Goldilocks conditions, metal machine life could arise, ab initio, and evolve viruses, intelligence, and civilizations, conjointly. Accordingly, intelligent mechanized civilizations could readily and efficiently commence space exploration. Furthermore, as a counter paradigm shift, such civilizations could experiment and produce non-metallic life, based on carbon and other non-metal elements, under suitable conditions, related to Goldilocks life. Even a single example of validated interstellar or intergalactic communication received on the Earth would support the existence of life elsewhere. However, the communication platform should not be restricted to electromagnetic radiation. Other platforms should be included as well - one such example, which would require sophisticated technology, is neutrino communication. This is the case for any advanced civilization, be it metal-machine based, biological-based, and carbon-based. In sum, civilizations based on machine life, would be highly productive due to the longevity and hardiness of machine life. However, significant caveats are raised in this brief report, because possibly dissimilar psychologies and intelligence may lead to conflicts between metal machine life and biological life, inter-paradigm conflict.     

Oxypred： Prediction and Classification of Oxygen-Binding Proteins

This study describes a method for predicting and classifying oxygen-binding pro- teins. Firstly, support vector machine (SVM) modules were developed using amino acid composition and dipeptide composition for predicting oxygen-binding pro- teins, and achieved maximum accuracy of 85.5% and 87.8%, respectively. Sec- ondly, an SVM module was developed based on amino acid composition, classify- ing the predicted oxygen-binding proteins into six classes with accuracy of 95.8%, 97.5%, 97.5%, 96.9%, 99.4%, and 96.0% for erythrocruorin, hemerythrin, hemo- cyanin, hemoglobin, leghemoglobin, and myoglobin proteins, respectively. Finally, an SVM module was developed using dipeptide composition for classifying the oxygen-binding proteins, and achieved maximum accuracy of 96.1%, 98.7%, 98.7%, 85.6%, 99.6%, and 93.3% for the above six classes, respectively. All modules were trained and tested by five-fold cross validation. Based on the above approach, a web server Oxypred was developed for predicting and classifying oxygen-binding proteins(available from http://www.imtech.res.in/raghava/oxypred/).     

国内8款常用植物识别软件的识别能力评价

随着智能手机和人工智能技术的发展, 以手机app为载体的植物识别软件慢慢走进公众生活、科普活动和科研活动的各个方面。植物识别app的识别正确率是决定其使用价值和用户体验的关键因素。目前, 国内应用市场上有许多植物识别app, 它们的开发目的和应用范围各异, 软件本身的关注点、数据库来源、算法、硬件要求也存在很大差异。对于不同人群, 植物识别app有不同的意义, 如对于科研人员来说, 识别能力强的app是提高效率的一大工具; 对植物爱好者来说, 具一定准确率的识别app可以作为入门的工具。因此, 对各app的识别能力进行分析与评价显得尤为重要。本文选取了8款常用的app, 分别对400张已准确鉴定的植物图片进行识别, 其中干旱半干旱区、温带、热带和亚热带4个区各选取100张。这些图片共计122科164属340种, 涵盖了乔木、灌木、草本、草质藤本和木质藤本5种生长型, 包含23种国家级保护植物。种、属、科准确识别正确分别计4分、2分、1分, 以此标准对软件识别能力按总得分进行排序, 正确率得分由高到低依次为花帮主、百度识图、花伴侣、形色、花卉识别、植物识别、发现识花、微软识花。