PLANTS CAN BE UNUSUAL
December 12, 2010
Q: You often
write about unusual characteristics of various animals. Do any plants
have properties that make them odd and fascinating as well?
A: To be
sure, many plants have distinctive, bizarre or unusual qualities. Among
the single-most basic essentials for any species of plant (or animal)
is that individuals must be able to feed themselves and obtain nutrients.
Plants have evolved some extraordinary attributes to achieve these goals.
speak of animals obtaining required nutrients, we refer to active foraging
and feeding behaviors. We don't ordinarily think of plants as aggressors.
But some plants actually capture and consume animals as part of their
diet. The best known example of this unusual behavior is found in pitcher
plants and Venus flytraps. These plants live in highly acidic wetland
habitats that are low in soil nutrients. In order to survive, the plants
must have some mechanism for supplementing their nutritional intake. They
do this by catching and digesting tiny animals.
plants are passive predators on insects or any other animal that is small
enough to fall into what is a highly effective pitfall trap shaped like
vase. In some pitcher plants the column is only a few inches high, but
the beautiful yellow trumpet pitcher plant of the Southeast can be almost
three feet tall. The inner surface of a pitcher plant tube, which has
downward-pointing hairs, is made slippery by secretions. A trapped prisoner
eventually falls into a digestive liquor at the bottom of the flask, which
means certain death for most of them. The bug that makes a misstep over
the edge of the tube soon becomes part of the plant world. In a manner
reminiscent of Audrey II in The Little Shop of Horrors, the plant digests
and gradually absorbs
much smaller than the showy pitcher plants, the Venus flytrap is a lot
faster in capturing its prey and does so with more pizzazz. A Venus flytrap
has modified leaves that perform a special magic trick for insects. The
two halves of the trap look like a large, opened butterbean with long
spines around the edges. The scent from nectar glands on the inside of
the open leaf attracts flies and other insects. When a bug alights and
its legs hit the hair triggers, the two halves of the trap slam shut faster
than a fly can fly. Now you see it, now you don't. The flytrap then secretes
digestive juices into the chamber, and over the next several hours the
insect is absorbed. An impressive magic trick indeed.
are not familiar to most people, but these carnivorous plants are abundant
and widespread. They get a major portion of their nutrients from animals
they catch. Their method of prey capture, rather like an aquatic version
of the Venus flytrap, is one of the most amazing feats of our native plants.
These small, mostly aquatic plants float at the water's surface armed
with thousands of bladders. A special trapping device about the size of
a match head targets swimming creatures such as small insects and protozoans.
If these tiny animals swim too close to the hair triggers on the outside
of the air-filled bladder trap, they become victims.
animal touches a trigger, a tiny door on the bladder trap snaps inward.
The helpless quarry is sucked inside with a rush of water. The door immediately
slams shut again, with the creature inside the bladder chamber, and the
digestive process begins. The bladderwort door opens and shuts in less
than 1/400th of a second, about as fast as plants can do anything. Bladderworts
are merciless with mosquito larvae, which squirm around so much they are
likely to hit a trigger eventually. Because the operation occurs at such
speed, it has been difficult to photograph, and for many years botanists
were unable to understand the bladderwort's process of capturing prey.
but a few of the traits that ensure that at least some plants can hold
their own with even the most bizarre and unusual animals.
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