Meristematic Tissues Morphology of Flowering Plants Video Lecture - Class

hello friends this video on tissue spat
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calm no move you from exam now again let
us have a quick look that where are the
meristematic tissues actually found as I
mentioned they are found in only some
specific regions of the plant where the
growth is good the growth is prominent
now based on which region of the plant
meristematic tissues are found they are
classified into three types ok so
depending upon where the best traumatic
tissue is located we will again the
people classify them into three
categories so what are the three
categories the first one is apical
medicine in technology medicine and the
last one is lateral meristem so these
are the three types of medicine
depending upon where they are found so
we will discuss about each of these
types in detail one by one but let us
quickly look at the location where they
are found as the name suggests apical
meristem epical it is derived from the
word FX FX means T so the berry stem
which is found in the tip of the plant
somewhere on the tip of plant they are
apical meristem okay then in the gallery
what is inter calorie the meristem which
are found somewhere in between in there
means something in between we say
intercellular that means between the
cells so the middle it is a medicine
which is found which which must be
located in between something so we will
look that in the next slide then we have
lateral meristem so maybe this kind of
metastable locate situated laterally so
laterally again decides the position of
something so now let us have a quick
look at the next light to see what are
these three types of main stem so let us
first look at the apical meristem as the
name suggests it is present at the apex
that is at the tips
so this present at
root and stem tips so it results in root
and stem length increase so this
meristem will actually result in growth
of the plant be it primary growth or
secondary growth so the apical meristem
it is present like the epochs that means
it is present at the tip of this stem
and also at the tip of the root so
therefore it will cause an increase in
length of the root it will cause an
increase in length of the stem so it is
actually causing a primary growth right
now this increase in root and shoot
length occurs due to send division and
cell enlargements right the cell keeps
on dividing so new and new node new and
new cells will be formed so which will
result in an increase in growth and also
due to cell enlargement the cells will
also increase in size so the increase in
cell number and increase in cell size
both together will result in an increase
in length of the stem or an increase in
length of the root right so this allows
the apical meristem let us now look at
the intercalary meristem what does an
intercalary meristem do first let us
look at where is it present it is
present at the base of leaves and Intel
nodes of twig so where is it actually
located it is located at the base of the
leaves and Internode's
of twins now what do I mean by Queens
when you look at a plant it will have
the stem the stem will give rise to
branches
right these branches will again give
rise pigs the twigs will give rise to
twiglets and so on this is how it
happens right so these kind of meristem
are present at the base of the leaves
somewhere here and they are also present
at the Intel loads of things now the
stem of the plant is divided into nodes
and Internode's if you look at a plant
you would see some regions like this
right so these regions are known as
nodes and these regions are known as
inter nodes and these are the places
places from where the branches are
arising right so this matters can
actually help in the growth of the
leaves and the growth of the twins so in
the tannery as the name suggests inter
calorie are present in the intent modes
that is why the name inter tannery
so from internodes you will have the
twigs you will also have the leaves so
it will actually help in the growth of
the branches which will again give rise
to twigs and twiglets right so it helps
in the growth of the plant that ways so
the apical meristem is increasing the
root and the stem so directly increasing
the length of the stem and the length of
the root intercalary meristem is
increasing the branches and the leaves
right so that is the intercalary
meristem now let us look at the third
type that is the lateral meristem so
what is the lateral meristem actually
doing alright so I hope you understood
what is the intercalary meristem right
so if you want I can draw the figure
separately if you have any doubts in
nodes and Internode's
see this is generally how the actually
the stem of plant look like so these
regions are nodes and these regions are
Intel nodes right so if you look at it
this is how the branches arise this is
how the leaves will also arise dead so
it actually helps in the growth of the
branches branch formation and also helps
in the growth of the leaves right okay
now let us look at the natural medicine
so what do you think the lateral
meristem do because you already saw
primary growth is handled by apical
meristem and the growth of branches and
leaves and twigs is handled by the
intercalary meristem so what is left now
the increasing width is left right which
we were talking less the secondary
growth so this lateral meristem will
cause an increase in the root or stem
girth what is this girth girth is
nothing but the thickness or we can see
the circumference of the bark let us
look at this tree so what do you think
would be the thickness or what do you
think is the circumference of this back
so this circumference of the bark is
known as gut now as a plant grows this
circumference also increases that means
the girth of the plant increases now
when this tree was just planted as a
small plant maybe the girth was
something like this now gradually with
due course of time it it underwent
growth and as a result the diameter of
the back increases or the circumference
increases right so this is known as this
is the secondary growth so the secondary
growth is handled by the lateral
meristem so the lateral meristem causes
an increase in the root and stem crop
good so it doesn't only happen with the
stem it also happens with the root you
will see that for a newly planted plant
if you take it out you will see that the
roots are very tiny and thin but if you
look at a tree like this I mean you just
cannot pluck it out it is so difficult
because the roots are thick and strong
enough right
so this secondary growth is handled by
lateral meristem now in lateral meristem
also we have two types one is
now the lateral medicine there is
another name for lateral meristem which
is cambium the lateral meristem is also
known as cambium so this lateral
meristem is actually handling the
secondary growth right so there are two
types of lateral meristem one is
vascular cambium and the other one is
cork cambium so at this level we will
not get into the detail of vascular
cambium and cork cambium but I am just
like to mention you what what is the
purpose I mean what is the difference
between a vascular cambium and a quad
cambium now vascular cambium is
responsible for the internal growth
internal growth of the girth because
wherever I am talking about cambium I am
just talking about the increase in gut
so the vascular cambium is responsible
for internal growth and the cork cambium
is responsible for the external growth
so if you want to see what is and what
where does these two different types of
cambium line you can just look at this
picture so this is a portion of the root
of a big tree so there if you cut the
root from between if you just take a
portion of the root it will look
somewhat like this it will have these
kind of rings you would have heard those
people of Archaeology they are looking
at this rings by Counting these number
of rings they do some calculation and
they can tell how old this tree is right
so this is how a bark actually looks
like with so many rings
now when I say call cambium call cambium
is this outer layer this layer which you
see in dark blue right so this outer
layer is the cord cambium which causes
an increase in growth externally so this
called cambium increases and therefore
the width increases whereas the vascular
cambium is this layer in light blue you
can see earlier in
bluelight this arrow is pointing to the
slight view layer so this light blue
layer will keep on increasing internally
so this will cause an increase in
internal growth so the vascular cambium
will keep increasing internally cork
cambium will keep increasing outer and
externally and as a result the width of
the tree or the girth of the root will
increase so this vascular cambium and
quad cambium together causes the
secondary growth in a plant right so I
hope you understood the three types of
meristematic issue that what are the
three types of meristems
the first was epical meristem which is
present at epochs and it causes primary
growth that is it causes increase in
length second was inter calorie which is
present at the inter nodes and it
results in branch formation at the nodes
third is lateral meristem or the cambium
which causes secondary growth because it
increases the girth of the root or stem
so here again we have two types vascular
cambium which causes internal growth and
cork cambium which causes the external
growth correct thank you please visit
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