Myco-Orchid Mycorrhyzal Relations

I think it is safe to say everyone loves orchids. And if by some chance you don't then you are dead to me, go read something else.

Now for all of you wonderful people that matter, which is of course everyone because nobody could belong to that other group, orchids are some an extremely diverse family of flowers. They grow all around the world and make up to about 10 percent of all seed plants. There are over 20,000 species which includes not only your typically prized Orchid flower but also things like vanilla. And guess what. Without fungi they wouldn't exist.

Dactylorhiza incarnata

You see, orchids are one of those many, many plants that rely on a mycorrhizal relationship with fungi to get nutrients. In fact some studies suggest that the distribution and specificity fungi are in part responsible for the rarity of some orchids. Recent research on the mycorrhizal relationships of Caladenia demonstrate that this in combination with other environmental goings on had a great impact on plant rarity.

A study recently out in PLoS One takes a look at this special relationship in five species from the Dactylorhiza genus.

Variation in Mycorrhizal Associations with Tulasnelloid Fungi among Populations of Five Dactylorhiza Species

The teams findings set to determine what species of fungi, as well as whether that specificity affected the rarity of species at least in this genus. And they found that the sampled Dactylorhiza species were not that stingy with whom they hooked up with.

On the five flower species they found 10 different isolatable fungal species with an average of 3 per plant (some had 2 others had 5 or six). The isolated fungi all came from the genus Tulasnella, which is a common symbiont of terrestrial orchids including several different genera. Most of the isolated Tulasnella species were found on more than one orchid of this study, and some of them were widespread amongst the specimens.

What this shows is that in contrast to the studies suggesting specificity amongst mycorrhizal symbionts, at least in Dactylorhiza a wide host of fungi could be utilized to get the job done. And while this study tackled whether or not mycorrhizal specificity was a major factor in Dactylorhiza, future tests focusing on other environmental conditions could help see if it triggered a constricted association. According to the researchers, more studies could also help determine what the purpose of multiple fungal infections is. Do they work in different ways to help acquire nutrients for the plant, or are they maybe competitors within the root system?



Awesome researchers:
Hans Jacquemyn, Agnieszka Deja, Koen De hert, Bruno Cachapa Bailarote, & Bart Lievens (2012). Variation in Mycorrhizal Associations with Tulasnelloid Fungi among Populations of Five Dactylorhiza Species PLoS One DOI: 10.1371/journal.pone.0042212

Photo Cred:
Roepers at nl.wikipedia