Structure and Function of the Ectomycorrhizal Association between Paxillus involutus (Batsch) Fr. and Betula pendula Roth. I. Dynamics of Mycorrhiza Formation

• Published in: The New phytologist Vol. 129; no. 3; pp. 487 - 493
• Main Authors: Brun, A., Chalot, M., Finlay, R. D., Soderstrom, B.
• Format: Journal Article
• Language: English
• Published: Oxford Cambridge University Press 01.03.1995; Blackwell
• Subjects: Agronomy. Soil science and plant productions; Betula pendula; Biological and medical sciences; Economic plant physiology; Ectomycorrhizas; Epidermal cells; Fundamental and applied biological sciences. Psychology; Hyphae; Infections; Mycorrhizas; Nitrogen; Parasitism and symbiosis; Paxillus involutus; Pendulums; Phosphorus; Plant physiology and development; Plant roots; Plants; Symbiosis; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); Symbiosis; Infection modality; Symbionte; Basidiomycetes; Phosphorus; Biosynthesis; Nitrogen; Fungi; Ultrastructure; Dicotyledones; Angiospermae; Mycorrhiza; Ectomycorrhiza; Hardwood forest tree; Spermatophyta; Developmental stage; Betula pendula; Betulaceae; Thallophyta
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.1995.tb04319.x

Detailed examination of the structural and functional integration taking place during mycorrhiza formation necessitates rapid and aseptic synthesis of uniform mycorrhizal structures at well-defined stages of development. A system is described for formation of ectomycorrhizas between Betula pendula Roth. and Paxillus involutus (Batsch) Fr. Small sterile seedlings were placed directly on fungal colonies growing on cellophane covered agar plates. Microscopic examination during the course of development indicated an initial rapid colonization of the roots and formation of a fully developed mantle within 2-4 d. Hartig net formation was evident after 8 d of contact and involved a transition from a paraepidermal organization to a mature periepidermal Hartig net after 15 d of contact. Using a standard fungal growth medium, formation and development of mycorrhizas were not greatly affected by changes in the overall concentrations of nitrogen and phosphorus but changes in the ratio of nitrogen to phosphorus had strong effects on development and mycorrhiza formation was completely suppressed when the ratio of nitrogen to phosphorus was increased. These differences were not related to the effects of nitrogen or phosphorus on linear growth of the fungus.