Ectomycorrhizal weathering of the soil minerals muscovite and hornblende

• Published in: The New phytologist 2006-01, Vol.171 (4), p.805-814
• Main Authors: Schöll, Laura van, Smits, Mark M, Hoffland, Ellis
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biological weathering; dissolution; ectomycorrhizal fungi; forest soil; Forest soils; Fundamental and applied biological sciences. Psychology; Fungi; hornblende; in-vitro; magnesium; mg2+ deficiency; Minerals; Minerals - chemistry; Minerals - metabolism; mobilization; Muscovite; Mycorrhizae - metabolism; organic-acids; Parasitism and symbiosis; Paxillus involutus; picea-abies; Piloderma croceum; Pine trees; Pinus - metabolism; Pinus - microbiology; Pinus sylvestris; Pinus sylvestris (Scots pine); pinus-sylvestris seedlings; Plant physiology and development; Plant roots; Plant Roots - metabolism; Plant Roots - microbiology; potassium; roots; Seedlings; Seedlings - metabolism; Seedlings - microbiology; Soil - analysis; Soil fungi; Soil solution; Suillus bovinus; Symbiosis; weathering
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2006.01790.x

• Ectomycorrhizal fungi are hypothesized to enhance mineral weathering in forest soils. Several studies have shown an increased uptake of mineral-derived nutrients by trees when in symbiosis with ectomycorrhizal fungi. However, it is difficult to determine from these studies if the improved nutrient uptake is the result of increased weathering or better exploitation of the substrate by the ectomycorrhizal fungi. • In a pot experiment, Pinus sylvestris (Scots pine) seedlings were grown with or without ectomycorrhizal fungi, and with or without the mineral muscovite as the only potassium (K) source or the mineral hornblende as the only magnesium (Mg) source. After 27 wk, all pools of non-mineral-bound K or Mg were determined. • The ectomycorrhizal fungus Paxillus involutus increased weathering of muscovite but not hornblende. The other ectomycorrhizal fungi tested, Piloderma croceum and Suillus bovinus, did not increase weathering of either muscovite or hornblende compared with the nonmycorrhizal trees. The P. involutus-mediated mobilization of K from muscovite resulted in increased K content of root plus adhering hyphae, but not of shoots. • In conclusion, ectomycorrhizal fungi may increase weathering of minerals in response to nutrient deficiencies, but this response is species specific.