presentation 1
DESCRIPTION
PTRANSCRIPT
Description
The Venus Flytrap, Dionaea muscipula, is a carnivorous plant that
catches and digests animal prey—mostly insects and arachnids. Its
trapping structure is formed by the terminal portion of each of the plant's
leaves and is triggered by tiny hairs on their inner surfaces. When an
insect or spider crawling along the leaves contacts a hair, the trap closes if
a different hair is contacted within twenty seconds of the first strike. The
requirement of redundant triggering in this mechanism serves as a
safeguard against a waste of energy in trapping objects with no
nutritional value.
The Venus Flytrap is a small plant whose structure can be
described as a rosette of four to seven leaves, which arise
from a short subterranean stem that is actually a bulb-like
object. Each stem reaches a maximum size of about three
to ten centimeters, depending on the time of year, longer
leaves with robust traps are usually formed after
flowering. Flytraps that have more than 7 leaves
are colonies formed by rosettes that have divided
beneath the ground.
Mechanism of trapping
The mechanism by which the trap snaps shut involves a complex
interaction between elasticity turgor and growth. In the open, untripped
state, the lobes are convex (bent outwards), but in the closed state, the
lobes are concave (forming a cavity). It is the rapid flipping of
this bistable state that closes the trap, but the mechanism by which this
occurs is still poorly understood. When the trigger hairs are stimulated,
an action potential is generated, which propagates across the lobes and
stimulates cells in the lobes and in the midrib between them
Digestion
If the prey is unable to escape, it will continue to stimulate the
inner surface of the lobes, and this causes a further growth
response that forces the edges of the lobes together, eventually
sealing the trap hermetically and forming a 'stomach' in
which digestion occurs. Digestion is catalvsed by
enzymes secreted by glands in the lobes. Digestion takes about
ten days, after which the prey is reduced to a husk of chitin. The
trap then reopens, and is ready for reuse.
Habitat
The Venus Flytrap is found in nitrogen-poor environments, such
as bogs and wet savannahs. Small in stature and slow growing, the Venus
flytrap tolerates fire well, and depends on periodic burning to suppress its
competition.Fire suppression threatens its future in the wild.It survives in
wet sandy and peaty soils. Although it has been successfully transplanted
and grown in many locales around the world, it is found natively only in
North and South Carolina in the United States, specifically within a 60-mile
radius of Wilmington, North Carolina. One such place is North
Carolina's Green Swamp.
There also appears to be a naturalized population of Venus
Flytraps in northern Florida as well as populations in the
New Jersey Pine Barrens. The nutritional poverty of the soil
is the reason that the plant relies on such elaborate traps:
insect prey provide the nitrogen for protein formation that
the soil cannot. The Venus Flytrap is not a tropical plant
and can tolerate mild winters. In fact, Venus Flytraps that
do not go through a period of winter dormancy will
weaken and die after a period of time.
Cultivation
Venus flytraps are popular as cultivated plants, but have a reputation for being
difficult to grow. Successfully growing these specialized plants requires recreating a
close approximation to the plant's natural habitat.
Healthy Venus flytraps will produce scapes of white flowers in spring, however, many
growers remove the flowering stem early (2-3 inches), as flowering consumes some of
the plant's energy, and reduces the rate of trap production. If healthy plants are
allowed to flower, successful pollination will result in the production of dozens of
small, shiny black seeds.
Plants can be propagated by seed, although seedlings take several years to mature.
More commonly, they are propagated by division in spring or summer.