Monday, 15 April 2013

Orchids and fungi

Some plants produce seeds that are so small that they do not have sufficient reserves to germinate underground unaided.

In fact, around 80 genera representing 10 per cent of plant species, most of which are orchids, are in this category. So instead, these plants parasitise soil fungi which supply the developing seedling with carbon and much of their mineral nutrient requirements (mycoheterotrophy).

Mycoheterotrophy is essential for establishment of gametophytes and seedlings of many “lower” and “higher” land plants. Although a widespread and common strategy for recruitment employed by many of the worlds’ most rare and threatened plant species, including most orchids, virtually nothing is known about the mechanisms required to parasitise fungi and how this strategy has evolved.

A PhD studentship has been advertised at the University of Sheffield, under supervisor Dr Duncan Cameron, with the aim of resolving the identity of the main metabolites passing from fungus-to-plant in mycoheterotrophy, as well as identify whether the major groups of mycoheterotrophic orchids exploit different metabolic pathways.

Pictured: Pacific coralroot is an example of a mycotrophic plant that obtains its organic carbon from a host green plant by tapping into an intermediary mycorrhizal fungus attached to the roots of the host plant