Premium
Fungal root colonization responses in natural grasslands after long‐term exposure to elevated atmospheric CO 2
Author(s) -
Rillig Matthias C.,
Field Christopher B.,
Allen Michael F.
Publication year - 1999
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1046/j.1365-2486.1999.00251.x
Subject(s) - colonization , symbiosis , biology , endophyte , grassland , colonisation , hypha , arbuscular mycorrhizal , botany , mycorrhiza , arbuscular mycorrhiza , ecology , bacteria , genetics
Summary Arbuscular mycorrhizae, ubiquitous mutualistic symbioses between plant roots and fungi in the order Glomales , are believed to be important controllers of plant responses to global change, in particular to elevated atmospheric CO 2 . In order to test if any effects on the symbiosis can persist after long‐term treatment, we examined root colonization by arbuscular mycorrhizal (AM) and other fungi of several plant species from two grassland communities after continuous exposure to elevated atmospheric CO 2 for six growing seasons in the field. For plant species from both a sandstone and a serpentine annual grassland there was evidence for changes in fungal root colonization, with changes occurring as a function of plant host species. We documented decreases in percentage nonmycorrhizal fungal root colonization in elevated CO 2 for several plant species. Total AM root colonization (%) only increased significantly for one out of the five plant species in each grassland. However, when dividing AM fungal hyphae into two groups of hyphae (fine endophyte and coarse endophyte), we could document significant responses of AM fungi that were hidden when only total percentage colonization was measured. We also documented changes in elevated CO 2 in the percentage of root colonized by both AM hyphal types simultaneously. Our results demonstrate that changes in fungal root colonization can occur after long‐term CO 2 enrichment, and that the level of resolution of the study of AM fungal responses may have to be increased to uncover significant changes to the CO 2 treatment. This study is also one of the first to document compositional changes in the AM fungi colonizing roots of plants grown in elevated CO 2 . Although it is difficult to relate the structural data directly to functional changes, possible implications of the observed changes for plant communities are discussed.