By Allison Kubo Hutchison
A scientific study of orchids revealed why they were so difficult to cultivate: they were missing an important aspect of the orchid habitat. Many orchid species rely on a complex symbiosis with fungi to propagate their seeds and to flourish in the wild. These fungi, broadly called orchids mycorrhiza, are specialized for each type of orchid and are often only found associated with their preferred orchid species. During the seed stage, these mutualistic fungi inhabit and feed the seed which did not evolve to have any nutrient stores on its own. The symbiosis of the two organisms continues through the orchid life cycle and various different fungi, each orchid having a multitude of cooperating species, feed the plant phosphorus, nitrogen, and carbon. When the fungal networks start to degrade the plants can even absorb them through their roots. As the orchid ages, the complexity and biodiversity of fungi that it partners with increases. Considering the immense biodiversity of orchids, orchids mycorrhizae represent approximately 10% of all botanical biodiversity on Earth.
In 1902, Lewis Knudson, a botanist at Cornell University, introduced a method to cultivate orchids mimicking the environment created by the symbiotic fungus. Using agar gel, or another rich nutrient broth, in an extremely sanitary environment the small seeds were able to grow. With the ability to grow from seed, horticulturists have made 100,000s of unique hybrid orchids and this has also brought the price down significantly. Still growing orchids is a laborious process and the beautiful grocery store variety takes years to grow from minuscule seeds to Mother’s Day gifts.
Image Credit: Illustration by Sarah Ann Drake from Sertum orchidaceum: a wreath of the most beautiful orchidaceous flowers (1838) selected by John Lindley.