Function of leaves in a Plant, Parts of a leaf Video Lecture - Class 6

it was really interesting to know about
various functions of the stem
can you tell me about the functions of
other parts of the plant also
yes why not let's learn about structure
and functions of a plant leaf different
plants have different types of leaves
these leaves are of different shapes
sizes and colors the part of the leaf by
which it is attached to the stem is
known as heo the broad green surface of
the leaf is known as La Mina
the lines on the leaf are all the winds
and the thick Wayne in the middle of
leaf is called midrib different types of
leaves have different arrangements of
veins this is known as leaf venation if
the veins make a net-like structure on
both the sides of the midrib it is
called reticulated venation
in some plants
the veins are arranged parallel to one
another it is known as parallel venation
let's do a fun activity with leaves
collect leaves of different shapes take
a paper sheet and colored pencils or
crayons put the paper on leaf as shown
in the figure hold the pencil tip
sideway and rub it on the portion of the
paper
having the leaf below it you will get
the leaf impression on the paper let's
have a quick look on the structure of a
leaf
Alif has the chill amina beans and
matrix now let's learn about the
functions of a leaf the primary function
of the leaf is to prepare food for the
planet the leaf is also known as the
food factory or kitchen of the plant
plant leaves prepare their food in the
presence of sunlight and a green colored
substance called chlorophyll which is
present in them this process is known as
photosynthesis leaves also use water and
carbon dioxide for this process and
release oxygen gas as a by-product have
you noticed how clean and fresh the air
feels when you are surrounded by a large
number of plants it is because plants
fill the air with oxygen which is
essential for all fast to live plus are
really lucky they do not have to chop
cook or bake their food they just sit
around and make their own food but tell
me something like I eat a variety of
food items water plants eat and how can
they say that only leaves prepare the
food for the plants and not the other
parts of the plant
let's see some interesting experiments I
am sure you will be able to find the
answers to your questions keep a potted
plant in a dark room
for two to three days after three days
take it out and cover one of its leaves
completely with black paper and keep the
plant in the sunlight
after one day remove the cover from the
leaf now plug the leaf covered with
black paper and one other leaf from the
plant take two test tubes put the two
leaves in different test tubes and fill
the test tubes with spirit keep the test
tubes in a beaker filled with water and
boil the water till all the green color
of both the leaves come out in the
spirit carefully take out the leads from
the test tubes and wash the leaves with
plain water after washing them keep them
on two different clean plates now put
few drops of iodine solution on both the
leaves iodine is an indicator and
indicator is a substance that indicates
the presence of another substance often
by changing color here we are using
iodine to indicate the presence of
starch that is a carbohydrate found in
plants I'd in solution on the uncovered
leaf turns into blue-black color which
is a positive iodine test on the other
hand when we put the iodine solution on
the covered leaf the color of solution
does not change which is a negative
iodine test
so you observed that the leaf which was
not covered gave the positive ID in
tests indicating the presence of starch
in the leaf since we did not cover this
leaf it was able to absorb sunlight and
manufacture its food whereas the leaf
which was covered gave negative ID in
tests which showing that there was no
starch in the leaf because of the
absence of sunlight the Coward leaf
could not produce the food the next
important function of the leaf is
transpiration take a potted plant cover
its leaves with a clean and dry
polythene bag and keep this plant under
direct sunlight for one day next morning
carefully observe the polythene bag you
will see small water droplets on the
inner surface of the polythene bag what
do you think from where have these water
droplets come inside the bag these water
droplets have come out of the leaves of
the plant in the flower vapor this
process is known as transpiration the
surface of a leaf has many tiny pores
called stomata the stomata a lot of
carbon dioxide into the leaf so that for
two surfaces can happen they also allow
water to go out of the leaf by
transpiration plants release water into
the air through transpiration and help
in maintaining the water cycle from
these experiments we learnt that the two
main functions of a plant leaf are
photosynthesis and transpiration so this
was all about the structure and
functions of the leaves of a plant hope
you enjoyed it
of course sir and I'm ready to learn
about rest of the parts of the plant
also