Insectivorous Plants Video Lecture | Science Class 7

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insectivorous plants one of the rarest
and most enigmatic species of plants in
the world is that of insectivorous
plants that get their nutrients by
trapping and consuming insects
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insectivorous plants are autotrophic in
nature and grow in water lock swampy
soils which are deficient in nitrogenous
compounds thus these plants do not get
their nitrogen requirements from the
soil but supplement the supply of
nitrogenous food by capturing and
digesting insects
thus the chief mode of nutrition in
these plants is photosynthetic and the
insectivorous habit is only an
adaptation to the environment in which
they live
these plants develop a great variety of
devices to capture insects there are
over 450 species of insectivorous plants
in the world leaves of some
insectivorous plants like Nepenthes
sarracenia civilities are modified into
pitchers to trap insects in Nepenthes
the lamina is modified into a pitcher
like structure the distal part of the
lamina forms a lid which covers the
mouth of the pitcher
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the lower part of the petiole becomes
flattened and leaf-like whereas the
upper part is coiled like a tendril and
holds the pitcher in a vertical position
a large number of glands are present on
the upper half of the inner wall of the
pitcher these sessile glands are of
epidermal origin and secrete proteolytic
enzymes on the rim of the pitcher
downwardly and inwardly directed hairs
are present which do not allow insects
to go out once they enter the pitcher
insects are attracted by the color of
the pitcher and the sweet secretions of
the glands as the insect enters the
picture it slips downwards and is
drowned in the fluid present in the
basal part of the pitcher this fluid
contains water and digestive juices
which devour the body of the insect the
digested food is then absorbed by the
pitcher in case of sarracenia the
pitcher is trumpet shaped it is a
modification of the winged petiole and
the lamina forms the lid here enzymes
are not secreted as in case of Nepenthes
insects captured by the pitcher are
decomposed by the action of bacteria
contained in the water present in the
pitcher
sefa latest follicle eres the Australian
pitcher plant is confined to the region
of King George's Sound in West Australia
and grows and marshes the rhizome
produces a rosette of leaves annually
the lower leaves of the rosette form
pitchers and the upper are flat and
green the pitchers resemble those of
Nepenthes or sarracenia venus flytrap
also known as daya Nia is a hub with a
rosette of leaves modified into fly
traps the broadly flattened petiole is
constricted to the midrib at its
junction with the lamina the roundish
lamina is divided into two almost
exactly similar halves separated by the
midrib the two halves of the lamina
which are like toothed jaw can move up
and down along the midrib they close
together with a snap and the two hairs
sets of teeth are interlocked to prevent
the escape of insects on the inner side
in the center of each upper surface of
each half there are three trigger hairs
which project outwards
if an insect comes in contact with a
trigger hair the stimulus moves to the
midrib which functions like a hinge
closing the leaf trap when the trapped
insect is digested and absorbed the trap
opens again water flea trap is a
submerged rootless aquatic which bears
walls of leaves and sends only its
flowers above the surface of water the
leaves resembled those of Dionaea with a
lower stock and an upper blade in two
halves working in the same way to catch
insects some do also known as traceur ax
is a help which grows in waterlogged
soil it has a rosette of 6 to 12 radical
leaves which lie prostrate on the ground
each leaf has a long narrow stalk which
is expanded into a more or less circular
blade the edges and the surface of the
blade there numerous bright red colored
club-shaped hairs known as tentacles
each tentacle is a stalked Musil each
secreting gland the tip of the gland
secretes a sticky juice which shines
like a dew drop in bright sunlight hence
the plant derives its popular mean some
do the glands act as capturing digesting
and absorbing organs insects are
attracted by the color glittering
secretion and order of the gland
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when an unwary insect alights on the
leaf it is helped by the visit secretion
of the glands
as the glands are sensitive to touch
they bend over the prey the secretion of
glands contains proteolytic enzymes that
digest the proteins of the prey which
are absorbed by the plant then the
tentacles return to their original
position
the non-digestible parts of the insect
are left exposed and are blown away
bladderwort also known as utricle area
is a rootless floating aquatic herb with
slender straggling branches and very
much dissected leaves some leaf segments
are modified into bladder like
structures the bladder is a stalked
pear-shaped structure opening at the
distal end the opening has a trapdoor
consisting of stiff tapering bristles
which can open only inwards the trap -
allows - water flies to pass in but they
cannot come out once trapped the flies
die in the bladder after they are
decomposed the nitrogenous substances
are absorbed through the hairs on the
inner wall of the bladder but a wart
also known as penguin Kuna is a help
with the rosette of large fleshy and
yellowish leaves the edges of the leaves
are slightly curled upwards forming a
kind of shallow trough
the leaf has two types of glands stopped
and sessile the stock gland has a large
basal cell a columnar cell and a head of
2 to 8 cells which produces mucus
material the sessile gland has a 2 to 8
celled head which secretes proteolytic
enzymes large drops of Musil is secreted
by the stalked glands help in the
capture of insects after the capture of
the insect the sessile glands are
stimulated and secrete enzymes acid
phosphatase esterase and ribonuclease
which help in the digestion of the
insect these glands also absorb the
digested food the species of
insectivorous plants is thus one of its
kind and hence also one of the most
fascinating ones existing on the planet
today
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you
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