Gochenaur S E
Mycopathologia. 1975 Dec 31;57(3):155-64. doi: 10.1007/BF00551422.
This study focuses on the characteristics displayed by mesophilous and thermophilous microfungal populations occurring in two tropical monodominant plant communities, a Cocos nucifera grove and a Casuarina equisetifolia forest, that provide distinctly different edaphic conditions. The mesophilous population sampled at 25 degrees C by the dilution plate method and the thermophilous population that developed on soil plates incubated at 45 degrees C consisted of 1693 isolates representing 60 species and 29 genera and 8887 isolates representing 20 species and 10 genera, respectively. The mesophilous propagules averaged 9,990 per gram dry soil in the coconut grove that lacks a litter layer, is low in moisture and organic matter and is subjected to high solar irradiation. The population was characterized by the prevalence of aspergilli and dematiaceous-sphaeropsidaceous forms and the near absence of mucoraceous isolates. Ascomycetes were common. The only widespread taxa were the three species, Aspergillus niger, Penicillium chysogenum, and Cladosporium cladosporioides. Species diversity was high and 73% of the isolates were cellulolytic. In the casuarina forest, adequate moisture and organic matter and a protecting litter layer provide a mesic environment. The mean number of mesophilous fungi per gram dry soil was 32,800. This figure is considerably lower than ones reported for mesic temperate communities and may be due to more rapid propagule removal through accelerated microfaunal and microbial activity. An abundance of mucoraceous and moniliaceous isolates and penicillia, and the rarity of aspergilli, dematiaceous-sphaeropsidaceous forms and ascomycetes characterize the population. The infrequency of aspergilli is thought to be due to their poor competitive ability. Eight species, Absidia cylindrospora, Penicillium notatum, Pestalotia cocculi?, Cylindrocarpon heteronema, Gliocladium roseum, Trichoderma viride, Paecilomyces marquandii, and Penicillium funiculosum were widespread in the area. Species diversity equaled that observed in mesic temperate communities. Less than one third of the isolates were cellulolytic. Phytopathogens were common, a feature characteristic of tropical populations. Thermophilous fungi averaged 33 per gram dry soil in the casuarina forest and increased to 943 per gram in the insolated soil of the coconut grove. Thermotolerant forms (94% of the isolates) were abundant and were principally species of Aspergillus and Chaetomium. Thermophilic fungi werur species, Ch. osmaniae, Ch. medusarum, Ch. sulphureum, and Thielavia arenaria, appear to be new records for western hemisphere soils.
本研究聚焦于两个热带单优势植物群落（一个椰子树林和一个木麻黄林）中出现的嗜温性和嗜热性微真菌种群所展现的特征，这两个群落提供了截然不同的土壤条件。通过稀释平板法在25摄氏度下采样的嗜温性种群以及在45摄氏度下培养的土壤平板上生长的嗜热性种群，分别由代表60个物种和29个属的1693个分离株以及代表20个物种和10个属的8887个分离株组成。在缺乏凋落物层、湿度和有机质含量低且遭受高太阳辐射的椰子树林中，嗜温性繁殖体平均每克干土有9990个。该种群的特征是曲霉菌和暗色球壳菌类形态普遍存在，而毛霉科分离株几乎不存在。子囊菌很常见。仅有的广泛分布的分类单元是黑曲霉、产黄青霉和枝孢霉这三个物种。物种多样性高，73%的分离株具有纤维素分解能力。在木麻黄林中，充足的水分和有机质以及保护凋落物层提供了一个湿润的环境。每克干土中嗜温性真菌的平均数量为32800个。这个数字明显低于报道的温带湿润群落的数字，可能是由于通过加速的小型动物和微生物活动，繁殖体去除更快。大量的毛霉科和链格孢科分离株以及青霉属，以及曲霉菌、暗色球壳菌类形态和子囊菌的稀少是该种群的特征。曲霉菌稀少被认为是由于其竞争能力差。柱状犁头霉、点青霉、樟疫霉、异孢柱孢霉、粉红粘帚霉、绿色木霉、马氏拟青霉和绳状青霉这八个物种在该地区广泛分布。物种多样性与温带湿润群落中观察到的相当。不到三分之一的分离株具有纤维素分解能力。植物病原体很常见，这是热带种群的一个特征。嗜热性真菌在木麻黄林中平均每克干土有33个，在椰子树林暴露的土壤中增加到每克943个。耐热形态（94%的分离株）丰富，主要是曲霉属和毛壳菌属的物种。嗜热性真菌物种，如奥斯曼尼毛壳菌、水母毛壳菌、硫磺毛壳菌和沙生嗜热栖热放线菌，似乎是西半球土壤的新记录。
