Book contents
- Frontmatter
- Contents
- Preface
- List of contributors
- 1 Factors influencing the germination and storage characteristics of orchid pollen
- 2 Effect of temperature and moisture content on the viability of Cattleya aurantiaca seed
- 3 Asymbiotic germination of epiphytic and terrestrial orchids
- 4 Germination and mycorrhizal fungus compatibility in European orchids
- 5 Host–fungus relationships in orchid mycorrhizal systems
- 6 The effects of the composition of the atmosphere on the growth of seedlings of Cattleya aurantiaca
- 7 Orchid propagation by tissue culture techniques – past, present and future
- 8 Population biology and conservation of Ophrys sphegodes
- 9 Predicting population trends in Ophrys sphegodes Mill.
- 10 Predicting the probability of the bee orchid (Ophrys apifera) flowering or remaining vegetative from the size and number of leaves
- 11 British orchids in their European context
- 12 The Nature Conservancy Council and orchid conservation
- 13 A private conservation project in the coastal rainforest in Brazil: the first ten years
- 14 The role of the living orchid collection at Kew in conservation
- 15 Import and export of orchids and the law
- Index
5 - Host–fungus relationships in orchid mycorrhizal systems
Published online by Cambridge University Press: 23 November 2009
- Frontmatter
- Contents
- Preface
- List of contributors
- 1 Factors influencing the germination and storage characteristics of orchid pollen
- 2 Effect of temperature and moisture content on the viability of Cattleya aurantiaca seed
- 3 Asymbiotic germination of epiphytic and terrestrial orchids
- 4 Germination and mycorrhizal fungus compatibility in European orchids
- 5 Host–fungus relationships in orchid mycorrhizal systems
- 6 The effects of the composition of the atmosphere on the growth of seedlings of Cattleya aurantiaca
- 7 Orchid propagation by tissue culture techniques – past, present and future
- 8 Population biology and conservation of Ophrys sphegodes
- 9 Predicting population trends in Ophrys sphegodes Mill.
- 10 Predicting the probability of the bee orchid (Ophrys apifera) flowering or remaining vegetative from the size and number of leaves
- 11 British orchids in their European context
- 12 The Nature Conservancy Council and orchid conservation
- 13 A private conservation project in the coastal rainforest in Brazil: the first ten years
- 14 The role of the living orchid collection at Kew in conservation
- 15 Import and export of orchids and the law
- Index
Summary
Summary
The understanding of the host–fungus relationships in the mycorrhizas of orchids is important in relation to the application of symbiotic methods to seed germination and seedling development, and also for re-establishment in natural conditions either from seed or tissue culture as one of the contributions to conservation. Despite extensive progress in knowledge of the role of fungi in the early stages of germination, the inherent difficulty in the use of the symbiotic technique has inhibited its application.
Orchid fungi are extremely variable and relatively few root inhabitants are true mutualistic symbionts. The outcome of the relationship between the partners is a finely balanced one and many fungi isolated from orchid mycorrhizas may, after a period in culture, become incompatible with, or even pathogenic to, orchid protocorms.
Mutualistically symbiotic fungi enhance the nutrition of germinating seeds by the transference of carbon compounds. Photosynthetically active seedlings and mature plants, however, may be quite independent of their fungal partners. Evidence suggests that in conditions of nutrient stress the fungal partner may mediate in the movement of phosphate and/or nitrogen compounds, as in other mycorrhizal systems.
Introduction
Orchids, whether epiphytic or terrestrial, generally grow and thrive in conditions of nutrient impoverishment. As with other higher plants growing in similar environments this may only be possible by the association of fungi with the roots and other subterranean parts – the mycorrhizal association.
- Type
- Chapter
- Information
- Modern Methods in Orchid Conservation , pp. 57 - 72Publisher: Cambridge University PressPrint publication year: 1989
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