Australia: The Land Where Time Began

A biography of the Australian continent 

These are restricted to the Ericales, that includes the Northern Hemisphere Ericaceae and in the Southern Hemisphere, Epacridaceae. They are the most common type in polar and alpine heathlands, areas where both temperature and evaporation are low, with most of the soil nitrogen unavailable in inorganic form. They are also typically found in some heaths of Mediterranean type, which are found in parts of Australia and South Africa. The Kwongan Sandplain flora of western Australia is one place where they are found, an area where a limiting factor is nitrogen. One reason for the low availability of nitrogen is the lack of water needed for the decomposition of dead plant material.

Ascomycetes are the type of fungi predominantly involved in this type of mycorrhiza. When hyphae penetrate the plant cell walls they form dense coils that are surrounded by the expanded plant cell membranes, greatly increasing the area available for nutrient exchange. The fungal hyphae develop in the surrounding soil to a more limited extent than in other forms, but the plant roots produce dense masses of very fine roots to assist the fungi to access large volumes of soil to access the organic nitrogen they then break down, passing some on to the host plant.

Sources & Further reading

Mary E. White, Earth Alive, From Microbes to a Living Planet, Rosenberg Publishing Pty. Ltd., 2003

• Arbuscular Mycorrhizas
• Ectomycorrhizas
• Ericoid Mycorrhizas
• Orchid Mycorrhizas