Video: Stem Parts Functions, Modifications Video Lecture - NEET

functions of the stem primary functions
the main function of the stem is to bear
and support leaves flowers and fruits
help in the upward conduction of water
and minerals from root help in the
downward conduction of manufactured food
from leaves to the other parts of the
plant
secondary or special functions the
secondary functions of the stem are
storage of food for example potato and
ginger vegetative propagation for
example potato and Rose it helps in
photosynthesis for example opuntia the
stem supports weak plant to climb as in
passion flower it protects the plant
from grazing animals for example taranta
and lemon
you
but condensed stems observe the portion
of the stem which shows the types of
buds terminal buds terminal buds are the
tip of the stem they are responsible for
the elongation of stem axillary bud
axillary buds are at the axle of the
leaf it produces branch or flower it is
responsible for sideward growth
comparison of stomata and lenticels
observe the diagram carefully to find
out the differences between lenticels
and stomata the differences between
lenticels and stomata are shown here in
the form of a table stomata are found in
young stems and leaves
whereas lent cells are found in older
stems guard cells are absent in stomata
whereas they are present in lenticels
stomata are open during the daytime
whereas lengths cells remain open all
the time both stomata and lenta cells
perform exchange of gases and
transpiration
stem modification the various types of
stem modifications have been tabulated
here stems may be modified for other
functions into aerial sub-aerial and
underground modifications the
modifications of aerial stems are stem
tendril thorn fellow clade trynna and
clad ode the main modifications of
sub-aerial stems are runner stolen
sucker and offset the underground stems
of different plants are modified into
rhizome cuba bulb and corn
underground stems the modifications of
underground stems of different plants
are shown here rhizome of ginger it is a
thick
prostrate and branched underground stem
it has distinct nodes and Internode's
adventitious roots of rhizome occur on
the lower side axillary buds of rhizome
arise on the axle of scaly leaves humor
of potato that is the swollen end of the
underground branch eyes of potato are
axillary buds with scar of the scale
leaf eyes denote the position of nodes
lenta cells can be observed as raised
spots on the tuber quorum quorum is a
condensed stem growing vertically into
the soil nodes and Internode's of corn
are not very distinct axillary buds grow
into daughter combs adventitious roots
are at the base bulb of onion it is a
highly condensed stem adventitious roots
arise from the base of the stem outer
scale leaves are dry and protective
inner scale leaves are fleshy and store
food
the diagram here shows the filler clade
of open Jie and clattered of asparagus
which are modifications of aerial stems
fill clade of open Jie stem are modified
into flat green and leaf like structures
which perform photosynthesis branches
show unlimited growth made up of a
number of nodes and Internode's leaves
are modified into spines to reduce
transpiration plateaued of asparagus
stems are modified into green and flat
leaf-like structures for photosynthesis
branches show limited growth and are
made up of usually only one internode
leaves are in the form of scale leads to
reduced transpiration
potato plant showing tubers observe the
potato plant showing lower branches
drawing tubers at their tips such
branches tend to grow downward the
farmers cover these parts by soil