中国南方地区暗色丝孢真菌三个新记录种（英文）

本文介绍暗色丝孢菌的3个新记录种,Exochalara guadalcanalensis、Monilochaetes regenerans、Catenularia piceae。对以上3个种进行详细的观察以及形态特征描述和图解。标本均保存于山东农业大学植物病理标本馆(HSAUP)。     

中国梧桐科上的尾孢类丝孢菌

报道生在中国梧桐科Sterculiaceae上的5种尾孢类丝孢菌（cercosporoid hyphomycetes）,其中在梧桐 Firmiana simplex 上新发现的2个新种,梧桐假尾孢 Pseudocercospora firmianae,梧桐生假尾孢 P. firmianicola和一个中国新记录种,野路葵假尾孢 P. corchorifoliae。提供了拉丁文特征简介、形态描述、绘图及讨论。研究的标本保存在中国科学院菌物标本馆（HMAS）。     

Food selection in three leaf-shredding stream invertebrates

Leaf disks (Betula papyrifera) were conditioned for two weeks by six species of aquatic hyphomycetes. Mass losses of the leaves were determined, and their concentrations of protein (extracted at pH 7, 10 and 12.8), phenolics (Folin-Ciocalteu and BSA-precipitation), lipids, and ergosterol (as indicator of fungal biomass) were measured. Enzymatic activities of the culture filtrates against cellulose, xylan and pectin were estimated. Gammarus tigrinis, Pycnopsyche guttifer and Tipula caloptera were given a choice of the six leaf/fungus combinations. G. tigrinus and P. guttifer consistently preferred some combinations over others; T. caloptera appeared to feed randomly. There were no significant correlations between consumption and any of the measured characteristics of leaf disks. With G. tigrinus and P. guttifer, the sequence of preference could be reproduced by extracting mycelia with non-polar solvents and applying the extracts to unconditioned leaf disks. Consumption of extract-coated disks was lower than consumption of conditioned disks. Numbers of endosymbiotic gut bacteria increased from G. tigrinus to P. guttifer to T. caloptera; diet diversity showed the opposite trend.     

Mycoleptodiscus terrestris from black pepper roots in the Dominican Republic

Mycoleptodiscus terrestris from black pepper roots in the Dominican Republic is described together with some notes and photomicrographs.     

Laccase activity of lignicolous aquatic hyphomycetes isolated from the River Nile in Egypt

Eleven species of aquatic hyphomycetes were isolated from 92 samples of different lignin sources (unidentified wood segments, skeleton and neck of leaves, bark). The most common species were Pyramidospora casuarina (on 3.7% of samples), Triscelophorus monosporus (3.2%) and Flagellospora curvula (3%). Varying levels of laccase activity were present in most of the fungi included in this study. The laccase plate assay was found to be much less reliable than the spectrophotometric assay. Several factors including type of growth medium, the media pH and assay pH had marked effects on laccase activity. A few species produced high levels of laccase in both malt extract (ME) medium and low N medium; however, a majority of the species produced laccase in low nitrogen (N) medium (pH 4.5) but not in the ME medium. When the tested species were grown in low N medium at pH 4.5, six species showed acidic laccase (pH 4.5) activity; of these, four also showed alkaline laccase (pH 8.2) activity. Alatospora acuminata and Tetracladium marchalianum exhibited laccase activity only when grown in the low N medium at pH 8.2. These results indicate that aquatic hyphomycetes may play a role in the decomposition of lignin materials in freshwater environments. This revised version was published online in June 2006 with corrections to the Cover Date.     

Materials for the fungus flora of Japan (57)

Two microfungi are described as new to Japan:Amaurascopsis reticulatus (Amauroascaceae, Ascomycetes), isolated from forest soil in Kamakura, has not been recorded since it was originally found and is characterized by yellow to orange-red ascomata with undifferentiated peridial hyphae and globose ascospores with contorted ridges appearing irregularly punctate-reticulate; andHobsonia mirabilis (helicosporous hyphomycete), isolated from the cut stem of a thistle in Hachijo-jima, is characterized by gelatinous sporodochia and hyaline, tortuously coiled conidia. (56): Okuda, T. and Yamamoto, K., Mycoscience41: 411–414, 2000.     

Magnitude and variability of process rates in fungal diversity-litter decomposition relationships

There is compelling evidence that losses in plant diversity can alter ecosystem functioning, particularly by reducing primary production. However, impacts of biodiversity loss on decomposition, the complementary process in the carbon cycle, are highly uncertain. By manipulating fungal decomposer diversity in stream microcosm experiments we found that rates of litter decomposition and associated fungal spore production are unaffected by changes in decomposer diversity under benign and harsher environmental conditions. This result calls for caution when generalizing outcomes of biodiversity experiments across systems. In contrast to their magnitude, the variability of process rates among communities increased when species numbers were reduced. This was most likely caused by a portfolio effect (i.e. statistical averaging), with the uneven species distribution typical of natural communities tending to weaken that effect. Curbing species extinctions to maintain ecosystem functioning thus can be important even in situations where process rates are unaffected.     

蜗孢属两个新种和一个中国新记录

蜗孢属隶属于子囊菌门Ascomycota毛筒壳科Tubeufiaceae,它们形态特征独特,能够产生多种活性次级代谢产物,具有一定的应用前景。本研究从中国海南省采集的腐木标本上分离到3种卷旋型丝孢真菌,通过ITS、LSU、RPB2和TEF1α多基因系统发育分析证据结合形态学特征,确定了它们的分类地位。结果表明,其中2个物种为蜗孢属新种,1个物种为中国新记录。为纪念李玉院士在中国菌物学界做出的贡献,本文特将其中一个新物种命名为李玉蜗孢菌。     

History matters: Heterotrophic microbial community structure and function adapt to multiple stressors

Ecosystem functions in streams (e.g., microbially mediated leaf litter breakdown) are threatened globally by the predicted agricultural intensification and its expansion into pristine areas, which is associated with increasing use of fertilizers and pesticides. However, the ecological consequences may depend on the disturbance history of microbial communities. To test this, we assessed the effects of fungicides and nutrients (four levels each) on the structural and functional resilience of leaf‐associated microbial communities with differing disturbance histories (pristine vs. previously disturbed) in a 2 × 4 × 4‐factorial design (n = 6) over 21 days. Microbial leaf breakdown was assessed as a functional variable, whereas structural changes were characterized by the fungal community composition, species richness, biomass, and other factors. Leaf breakdown by the pristine microbial community was reduced by up to 30% upon fungicide exposure compared with controls, whereas the previously disturbed microbial community increased leaf breakdown by up to 85%. This significant difference in the functional response increased in magnitude with increasing nutrient concentrations. A pollution‐induced community tolerance in the previously disturbed microbial community, which was dominated by a few species with high breakdown efficacies, may explain the maintained function under stress. Hence, the global pressure on pristine ecosystems by agricultural expansion is expected to cause a modification in the structure and function of heterotrophic microbial communities, with microbially mediated leaf litter breakdown likely becoming more stable over time as a consequence of fungal community adaptions.