Temporal variation in mycorrhizal diversity and carbon and nitrogen stable isotope abundance in the wintergreen meadow orchid Anacamptis morio

Abstract

SummaryMany adult orchids, especially photoautotrophic species, associate with a diverse range of mycorrhizal fungi, but little is known about the temporal changes that might occur in the diversity and functioning of orchid mycorrhiza during vegetative and reproductive plant growth.Temporal variations in the spectrum of mycorrhizal fungi and in stable isotope natural abundance were investigated in adult plants of Anacamptis morio, a wintergreen meadow orchid.Anacamptis morio associated with mycorrhizal fungi belonging to Tulasnella, Ceratobasidium and a clade of Pezizaceae (Ascomycetes). When a complete growing season was investigated, multivariate analyses indicated significant differences in the mycorrhizal fungal community. Among fungi identified from manually isolated pelotons, Tulasnella was more common in autumn and winter, the pezizacean clade was very frequent in spring, and Ceratobasidium was more frequent in summer. By contrast, relatively small variations were found in carbon (C) and nitrogen (N) stable isotope natural abundance, A. morio samples showing similar 15 N enrichment and 13 C depletion at the different sampling times. These observations suggest that, irrespective of differences in the seasonal environmental conditions, the plant phenological stages and the associated fungi, the isotopic content in mycorrhizal A. morio remains fairly constant over time.

Mycorrhizal fungi affect orchid distribution and population dynamics

“…Mature orchids will be indicative of locations where OMFs are consistently abundant. A handful of studies have now documented changes in OMF communities in orchid roots with season and habitat (Kohout et al, 2013;Ercole et al, 2015;Oja et al, 2016;Han et al, 2017), but understanding how these changes impact orchid distribution and population dynamics awaits further study.…”

Fungal and plant gene expression in the Tulasnella calospora–Serapias vomeracea symbiosis provides clues about nitrogen pathways in orchid mycorrhizas

“…The ability of orchid mycorrhizal fungi to use different N sources has important ecological implications because most photoautotrophic orchids host a diverse community of orchid mycorrhizal fungi in their roots and protocorms, often including both Tulasnella and Ceratobasidium species (see e.g. Jacquemyn et al, 2010;Girlanda et al, 2011;Ercole et al, 2015). Co-occurrence of fungal symbionts able to utilize a wide variety of nutrient sources and to exploit different soil N forms would represent an advantage for the host plant because it could broaden the habitat range as well as the ability of the orchid to grow in a wide range of soil types (Nurfadilah et al, 2013).…”

Fine‐scale spatial distribution of orchid mycorrhizal fungi in the soil of host‐rich grasslands

“…It is located 460 m above sea level, in a transition zone between Mediterranean and sub-Atlantic climates. This area features a high richness in orchid species (Girlanda et al, 2006(Girlanda et al, , 2011Ercole et al, 2014). We focused on Anacamptis morio Bateman, Pridgeon & Chase and Ophrys sphegodes Mill., two widespread Euro-Mediterranean orchids growing in grassland habitats (Kretzschmar et al, 2007).…”

“…We focused on Anacamptis morio Bateman, Pridgeon & Chase and Ophrys sphegodes Mill., two widespread Euro-Mediterranean orchids growing in grassland habitats (Kretzschmar et al, 2007). Both species belong to the Orchideae tribe in the Orchidoideae subfamily of Orchidaceae (Bateman et al, 2003), and have been described as fully photoautotrophic orchids (Liebel et al, 2010;Ercole et al, 2014). They are winter-green perennial tuberous plants in which, after summer dormancy, the underground bulbous tuber produces a basal rosette of leaves and some roots.…”