L22 : Xylem & Phloem - Transport in Plants Animals, Science, Class 7 Video Lecture

hello friends this video on transport in
plants and animals part 22 is brought to
you by exam for calm no more fear from
exam so let us not talk in detail about
Zygon so let us try to understand the
structure of salmon so xylem are mostly
dead cells so the cells of xylem are not
living now this xylem in turn is also
made up of many different elements or
you can say there are many different
parts of xylem so this consists of
tracheids
and vessels so these tracheids and
vessels they are the real vessels as the
name suggests think this is how they
look like so you see vessels are little
by the tubes
whereas tracheids are comparatively
slender tubes with tapered ends so
structure wise they are different even
if you get deep into their functionality
so you will be able to find some
differences between them but as of now
at this level you really do not need to
know so much details but just to tell
you that enzyme and these are the most
important elements because they help in
the actual process of transport so these
are the Buehler structures like tubes
just that this is little wide and this
is comparatively narrow tube so they
conduct water and minerals vertically
and this helps an upward movement of
water and minerals
the next element are xylem panel thymus
so this is how they look Sicilian
parenchyma again another cell which
helps in storage of food they help to
store food for storing food is also
important right because the end of the
day they also need some amount of food
to do their job and xylem fibers so
silent fibers are just to provide
support to these xylem vessels because
they need enough mechanical support to
be there so the main most important
function of Zion
that is conduction is performed by
brackets and vessels which are tabular
structure and therefore helps an upward
movement of water and minerals so these
tracheids and vessels both of them are
held full in conduction in case of
flowering plants and in case of non
flowering plants these traffics are not
useful let us look at flow and now
so these flowing and living cells like
in case of Zion they are all dead but
phloem are all living cells except
phloem fibers so let us look at the
various elements of phloem sieve tubes
as the name suggests these are against
tubular structure which is going to help
in transportation of food so these are
tabular cells with perforated walls that
is their walls have holes or tiny pores
and through these pores they actually
help in communicating with the other
sieve tubes or with the other cells and
that's how it helps in transportation of
food
next is companion cells so as you can
see here these cells are the companion
cells which regulates the metabolic
activities of sieve-tube elephants so
these three tubes are actually supported
by the companion cells then you have
flowing parenchyma which is again used
for storage of food now parenchyma cells
whether it is xylem balón time' or all
flowing parenchyma they help in storage
of food and the fibers they provide
mechanical support like how in use of
xylem also you have to design in fibers
to provide mechanical support here also
flowing fibers support mechanically so
in this case the actual job of
conduction is done by the sieve tubes
and on with the companion cells so this
is how the structure of xylem
um looks like you will study about their
structures in more detail in your higher
classes so what are the things that are
conducted by these sieve tubes so they
conduct food they also conduct amino
acids they also conduct hormones so
these are some of the things which are
conducted by me safe tubes of flow so
let us have a quick comparison of xylem
and phloem so in case of xylem it is
always unidirectional transport because
the transportation happens from roots to
other parts of the plant so therefore
the movement of or the transport will
always happen in the upward direction
but in phloem it is by dimensional
transport because the time sport has to
happen from leaves to be is part of the
plant in seinem it deals with transport
of water and minerals in phloem it deals
with transport of food and nutrients
xylem cells are all dead tissues but
flowing cells are giving tissues so
location by xylem occurs at the center
of vascular bundle whereas flowing
occurs on the outer side so if you look
at the cross section of the plant stem
what you can see is you see xylem occurs
towards the inner side whereas the
flowing up always occurs towards the
outer cells so that's how their location
is also different now if you I mean if
you actually want to understand how
exactly this conduction happens let me
give you one example of conduction by
xylem
let us suppose this is your soil and
soil contains water
it also contains minerals which are
important for the plants so how are
these water and minerals absorbed from
the soil with the help of root hairs of
the plant now once these have been
observed by absorbed by the root hairs
then it gets into the xylem vessels of
rooms so the xylem vessels of roots will
actually carry or transport these water
and minerals and then
xylem vessels of roots will carry them
to the xylem vessels of stem from the
xylem vessels of stem the vessels and
tracheids
will carry them vessels and rackets are
nothing but the xylem vessels again so
they will carry them to the leaf veins
so that is how you see every part of the
plant will have their own set of xylem
vessels that is vessels and Tracking's
then these vessels and trackage will
actually help to conduct the water and
minerals from roots to the leaves so
that's how conduction happens with the
help of xylem and phloem vessels so
based on whatever we have studied so far
if we take this example of this plant so
what can be seen
xylem and phloem are basically vessels
that is their tube like structures which
help to conduct between various plant
parts so when we talk about Zion it only
helps in transport of water and minerals
in this direction that has strong roots
towards the leaves but in case of phloem
it is a bi-directional transport so from
leaves it also transports downward
towards the roots and from leaves it
also helps to transport upwards towards
the higher branches and leaves so that
is the overall a function of xylem and
phloem and structure wise that only that
element of xylem and phloem actually
help in conduction which articular
structures like in case of xylem vessels
and trap himself and in case of phloem
it is the sieve tubes in case of flows
who help in real compaction sieve tubes
along with the companion cells thank you
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