Page 8 - Ninja Plants: Survival and Adaptation in the Plant World

A VARIETY OF STINKY SMELLS

Not all plants that stink smell alike. The skunk cabbage (Symplocarpus
foetidus), common to North America and Asia, has a smell that fits its
descriptive common name. If you crush the leaves of this plant, the
odor is more like a skunk’s nasty spray than a fresh spring breeze. The
plant also emits this smell when its flower blooms. The smell attracts
pollinators such as flies, bees, and carrion beetles. This symbiotic
arrangement, in which the plant relies on insects for fertilization and
the insects benefit from drinking the plant’s nutrient-rich nectar, is a
common evolutionary adaptation in plants. The plant’s smell and the
burning sensation from eating the plant or coming in contact with its
broken stems is a defense mechanism that wards off larger animals that
might damage or eat the plant.
The skunk cabbage has something else in common with the dead
horse arum—it gives off heat through thermogenesis. In fact, its
internal temperature can be up to 36°F (20°C) warmer than the outside
air. What is this heat for? In winter the extra heat the skunk cabbage
generates melts the snow and thaws out the frozen ground surrounding
the plant. When the ground thaws, skunk cabbage seeds sprout and
begin to grow. This is a competitive advantage in the plant world. It
gives the skunk cabbage a jump start for spring. The early-sprouting
skunk cabbage plant grabs the best nutrients in the surrounding soil,
loads of extra sunshine, and more insects for pollination than other
nearby plants. As they say, the early bird gets the worm!
The stinking hellebore (Helleborus foetidus), native to central and
southern Europe, is another plant that lives up to its odorific name. The
plant’s lime-green flowers are beloved features in floral arrangements,
and the plant doesn’t normally have a pungent odor. However, its leaves
react like those of the skunk cabbage under one specific condition. If
the leaves are crushed, such as when an animal steps on the plant, the
contact activates a surprisingly strong odor. This skunky smell is a great
defensive adaptation to ward off predator animals. However, that’s only
one of the plant’s ninja-like tricks. Yeast organisms inside the plant’s
nectaries (glands in the ovaries) can raise the temperature of the plant,
which releases odiferous chemicals that attract pollinators.

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N I NJ A P L AN T S