Swiss Federal Research Institute WSL, Zürcherstrasse 111, Birmensdorf, Switzerland.
Plant Biol (Stuttg). 2013 Jan;15 Suppl 1:230-7. doi: 10.1111/j.1438-8677.2012.00614.x. Epub 2012 Jun 11.
The present study aimed to elucidate the influence of drought and elevated temperature on relative abundance and functioning of the ectomycorrhizal fungus Cenococcum geophilum on three oak species differing in adaptation to a warm and dry climate. The experiment QUERCO comprised three Quercus species (Q. robur, Q. petraea, Q. pubescens) grown for 3 years under four treatments: elevated air temperature, drought, a combination of the two, and control. Fine root samples were analysed for relative abundance and potential extracellular enzyme activities of ectomycorrhizae of C. geophilum, a fungal species known to be drought resistant. The relative abundance of C. geophilum on the roots of the oak species was significantly increased by temperature, decreased by drought, but unchanged in the combined treatment compared to the control. Although the extent of treatment effects differed among oak species, no significant influence of tree species on relative abundance of C. geophilum was detected. Exoenzyme activities of C. geophilum on Q. robur and Q. petraea (but not Q. pubescens) significantly increased in the combined treatment, but for all oak species were reduced under drought and air warming alone compared to the control. There was a significant negative correlation between abundance of C. geophilum and its leucine aminopeptidase activity. As this enzyme is not frequent among ectomycorrhizal fungi, this emphasises the functional importance of C. geophilum in the ectomycorrhizal community. Our results indicate that increased temperature and drought will influence the relative abundance and enzyme activity of C. geophilum. However, both the Quercus species and C. geophilum tolerated warming and strong drought.
本研究旨在阐明干旱和高温对适应温暖干燥气候的三种栎属树种（欧洲栎、欧洲栓皮栎、欧洲山毛榉）外生菌根真菌共生体胶膜菌相对丰度和功能的影响。实验 QUERCO 包括三个栎属树种（欧洲栎、欧洲栓皮栎、欧洲山毛榉），在四个处理条件下生长了 3 年：升高的空气温度、干旱、两者的组合和对照。对胶膜菌的外生菌根相对丰度和潜在的胞外酶活性进行了分析，胶膜菌是一种已知耐旱的真菌物种。与对照相比，温度升高显著增加了栎属树种根上胶膜菌的相对丰度，干旱降低了其相对丰度，但组合处理则没有变化。尽管处理效应的程度在栎属树种之间存在差异，但树种对胶膜菌相对丰度的影响并不显著。胶膜菌对欧洲栎和欧洲栓皮栎（而非欧洲山毛榉）的胞外酶活性在组合处理中显著增加，但与对照相比，在单独干旱和空气升温处理下，所有栎属树种的胞外酶活性都降低了。胶膜菌的丰度与亮氨酸氨肽酶活性呈显著负相关。由于这种酶在外生菌根真菌中并不常见，因此这强调了胶膜菌在共生体中的功能重要性。我们的研究结果表明，温度升高和干旱将影响胶膜菌的相对丰度和酶活性。然而，栎属树种和胶膜菌都耐受了变暖和强烈的干旱。
