Background and Aims

Pinus cembra represent a typical and important tree species growing in European subalpine and alpine habitats. The ectomycorrhizal (ECM) fungal communities associated to this tree under natural conditions are largely unknown.

Methods

In this study, we investigated the ECM fungal abundance and composition at four high-altitude sites (two northern-exposed and two southern-exposed habitats) in South Tyrol (Italy), and included also two different age classes of P. cembra. The ECM partners were characterized morphologically, and identified by rDNA ITS sequence analysis.

Results

The degree of mycorrhization in adult P. cembra was typically 100% in these natural habitats, with a total species diversity of 20 ECM species. The four high-altitude sites were similar concerning their species richness and mycobiont diversity, but they differed significantly in ECM species composition. Young P. cembra had a mycorrhization degree of 100% and a total of 10 species were observed. All mycorrhizal partners of naturally regenerated young P. cembra were only detected in one specific location, with the exception of Cenococcum sp. and Amphinema sp. which were detected at two sites. Young trees harbour a distinct ectomycorrhizal fungal diversity, which is clearly lower than the diversity detected in adult P. cembra trees. The P. cembra bolete (Suillus plorans) is the most important symbiotic partner of P. cembra at Southern Tyrolean high-altitude sites and is known for its strict, species-specific host association.

Conclusions

The ectomycorrhizal fungal community composition strongly depends on geographic region and on the slope exposure (north or south) of the site.

中文翻译：

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瑞士石松 (Pinus cembra) 的外生菌根真菌群落取决于阿尔卑斯山天然森林的气候和树龄

背景和目标

Pinus cembra是生长在欧洲亚高山和高山栖息地的典型且重要的树种。在自然条件下与这棵树相关的外生菌根 (ECM) 真菌群落在很大程度上是未知的。

方法

在这项研究中，我们调查了南蒂罗尔（意大利）四个高海拔地点（两个朝北和两个朝南的栖息地）的 ECM 真菌丰度和组成，还包括两个不同年龄等级的P. cembra。ECM 伙伴在形态学上进行了表征，并通过 rDNA ITS 序列分析进行了鉴定。

结果

在这些自然栖息地中，成年P. cembra的菌根化程度通常为 100%，总物种多样性为 20 种 ECM 物种。四个高海拔地点的物种丰富度和真菌生物多样性相似，但它们在 ECM 物种组成方面存在显着差异。Young P. cembra的菌根化程度为100%，共观察到10个菌种。自然再生的年轻P. cembra的所有菌根伙伴仅在一个特定位置检测到，除了Cenococcum sp。和安非尼玛sp。在两个地点检测到。幼树具有明显的外生菌根真菌多样性，这明显低于在成年P. cembra树中检测到的多样性。P. cembra bolete ( Suillus plorans ) 是南蒂罗尔高海拔地区P. cembra最重要的共生伙伴，并以其严格的、物种特异性的宿主关联而闻名。

结论

外生菌根真菌群落组成很大程度上取决于地理区域和场地的斜坡暴露（北或南）。