Blueberry plants are sugar factories. They capture the plentiful sunlight energy and use it to manufacture fructose from water and carbon dioxide. But neither a plant nor a six-year old (or a berry-picking naturalist) can live on sugar alone, try as they might. In this thin, rocky soil, getting the right suite of nutrients and water for growth can be tough. The blueberry plants have helpers, though, just like many other plants in their Heath Family.
If
you, or a plant biologist, were to stain a blueberry root with dye and view it
through a microscope, you would see thin strands of fungal hyphae coiled within
the root cells and extending in thin threads outside the root. The hyphae act
like root-extensions, drawing in nutrients and water beyond the typical reach
of the blueberry. The fungus, a decomposer, can break down soil components to
access nutrients that are otherwise locked away. The blueberry pays for this
service by giving the fungus little sugar snacks.
The
blueberry’s mycorrhizal (fungus-root) relationship is wholesome compared to some
of its close kin. Those shady cousins have a more deceitful way to make a
living.
Back
in the forest, layer upon layer of leaves filter out most of the noontime light
before it reaches the forest floor. Red-capped Russula mushrooms with white stalks brighten up the brown leaf
litter. The few understory species that can survive here must have low energy
needs, and an ability to take advantage of sun whenever they catch a fleeting
glimmer. Or they might be theives.
While
your stereotypical burglar dresses in all black, one bandit shines with the
translucent white glow of innocence. Sometimes called Indian pipe, ghost plant,
or corpse plant, the cluster of eight-inch tall flower stalks is actually a
cousin of blueberries and cranberries that takes the mycorrhizal relationship
to the extreme. Indian pipe has no chlorophyll to make it green, and therefore
cannot carry out photosynthesis. It does not need to make food, because this myco-parasitic
plant is getting ALL of its food from a fungus.
It
just so happens that some of the most common fungal providers for Indian pipe
are Russulas, those pretty red
mushrooms that are popping up everywhere right now. These fungi are engaged in
their own mycorrhizal relationship with the trees, and are currently exchanging
micro-nutrients and water for the sweet products of photosynthesis. Indian pipe
fools the fungus into “thinking” they are forming a mycorrhizal relationship.
Then it steals the sugars, giving nothing in return. Scientists have traced the
one-way flow of sugars by introducing radioactive carbon into tree leaves,
watching it flow down through the Russula,
and out into the Indian pipe, where it stays.
In
both sunlight and shadow, the intricate relationships of nature fill our lives
with sweetness and beauty.