Monotropa uniflora is a small
non-photosynthetic plant that lives in wooded areas containing deep humus
in the northern hemisphere. The single flower on each plant remains
downward facing until it is fertilized by insects, at which time the flower
begins to slowly turn upward until it is completely erect. It is
the erect flower which will soon turn into the fruit, per se, of the plant
and render seeds. After seeds have been released the plant begins
to turn black and die. Remains of dead plants can often be seen in
and among living ones.
Since this plant contains no photosynthetic
mechanisms it must acquire its energy source elsewhere. The habitat
of this plants offers the perfect opportunity. In the early days
of it's discovery many botanists thought it to be parasitic on the roots
of certain trees indigenous to the areas in which it was found. Their
assumptions were good for their time since the plant was almost always
growing on top of existing tree root systems, many times both root systems
would be in direct contact. However it was found in later studies
that Monotropa uniflora did indeed get some of its energy from the
surrounding trees but it was through a complex association with a species
of fungus and not direct contact with trees.
The fungus which is also found
in close proximity to the tree roots takes nutrients from the roots of
the tree and in turn Monotropa uniflora takes nutrients from the
mycorrhiza. This theory was tested by Nancy Gamble Walker Baker at
the University of Georgia in the late 60's and early 70's. Mrs. Baker
isolated Monotropa uniflora growing in the wild. She then
injected radioactive 14C into the phloem of the trees and four
days later found the radioactive isotope in the Monotropa spp.
The Monotropa spp. was also shown not to be able to survive
without the fungus present thus showing the connection between tree, fungus,
and plant. (Baker, 1971)