PLANT TISSUES | EASY to UNDERSTAND
Summary
TLDRIn this engaging biology lesson, Miss Angler simplifies the study of plant tissues for students. She differentiates between meristematic and permanent tissues, explaining their roles and appearances under a microscope. From apical and lateral meristems to epidermis, parenchyma, and vascular tissues like xylem and phloem, she breaks down complex concepts into digestible information, ensuring students can identify and understand the functions of each tissue type, enhancing their exam preparation.
Takeaways
- 🌱 Plant tissues are categorized into meristematic (temporary, for growth) and permanent tissues.
- 🌳 Meristematic tissues differentiate into permanent tissues like parenchyma, collenchyma, sclerenchyma, xylem, and phloem over time.
- 🌿 Apical meristems at the tips of shoots and roots are responsible for primary growth, making plants grow upwards and roots grow downwards.
- 🌲 Lateral meristems, like the cambium, are involved in secondary growth, thickening stems and providing bark on trees.
- 🛡️ The epidermis is a protective permanent tissue with specialized cells like stomata and root hair cells for gas exchange and nutrient absorption.
- 🌬 Stomata are specialized epidermal structures consisting of guard cells that regulate gas exchange and water loss.
- 🌼 Parenchyma is the most abundant tissue in plants, providing support, storage, and gas exchange through its thin cell walls and intercellular airspaces.
- 🌿 Chlorenchyma is a type of parenchyma containing chloroplasts, enabling photosynthesis and giving stems a green and fleshy appearance.
- 🌳 Collenchyma is characterized by unevenly thickened cell corners, providing flexible support to plant stems.
- 🏗️ Sclerenchyma has evenly thickened cell walls and is divided into fibers found in wood and bark, and sclereids found in nuts and stone fruits.
- 🚰 Xylem is responsible for unidirectional transport of water and minerals from roots to shoots, with cells that are dead, empty, and thickened with lignin.
- 🍬 Phloem transports sugars bidirectionally, moving from leaves to roots and vice versa, with sieve plates for lateral movement of substances.
Q & A
What are the two main forms of plant tissues mentioned in the script?
-The two main forms of plant tissues mentioned are meristematic tissue, which is temporary and involved in growth, and permanent tissue, which lasts longer and includes types like parenchyma, collenchyma, sclerenchyma, and vascular tissues such as xylem and phloem.
What is the primary function of apical meristems in plants?
-Apical meristems are responsible for primary growth, causing the lengthening of the plant, which allows plants to grow upwards towards the sun and roots to grow downwards towards water and soil.
How does the cambium contribute to the growth of a plant?
-The cambium is a ring of tissue that allows for secondary growth, making the plant stems thicker over time. It is also responsible for providing bark on trees as the stem widens.
What is the main purpose of the epidermis in plants?
-The epidermis serves a protective role, shielding everything beneath it and ensuring that the underlying tissues can perform their functions effectively.
What is the role of stomata in plant leaves?
-Stomata are specialized openings on the underside of leaves, guarded by guard cells, which regulate the exchange of substances like gases and water vapor, facilitating processes such as photosynthesis and transpiration.
What are the two main functions of root hair cells?
-Root hair cells improve the surface area of the plant for better nutrient absorption from the soil and have a large vacuole to store water or minerals before they are distributed within the plant.
How does the structure of parenchyma cells relate to their function in plants?
-Parenchyma cells have thin cell walls and intercellular airspaces, providing a spongy, soft, and flexible structure that allows for storage and gaseous exchange within the plant.
What distinguishes collenchyma from parenchyma in terms of cell structure?
-Collenchyma cells are distinguished by their unevenly thickened corners, providing support and strength while maintaining flexibility and the ability to photosynthesize due to the presence of chloroplasts.
How does the structure of sclerenchyma cells differ from that of collenchyma cells?
-Sclerenchyma cells have evenly thickened walls as opposed to the uneven thickening in collenchyma, providing rigidity and strength, and are typically found in roots, stems, and branches, as well as in the form of fibers in wood and bark or as sclereids in nuts and stone fruits.
What is the primary function of xylem in plants?
-The primary function of xylem is to transport water and minerals from the roots to the shoots in a one-directional movement, utilizing elongated cells with large lumens and thickened walls reinforced with lignin.
How does the structure of phloem cells differ from that of xylem cells, and what is the function of phloem?
-Phloem cells have sieve plates that allow for the movement of sugars and other organic compounds. Unlike xylem, phloem transports sugars in a two-way movement, from the leaves where they are produced to the rest of the plant for storage or immediate use.
Outlines
🌿 Introduction to Plant Tissues
This paragraph introduces the topic of plant tissues, focusing on how to identify and study them for exams. The speaker, Miss Angler, aims to simplify the process of distinguishing between different types of tissues, their functions, and their appearance under a microscope. The paragraph also mentions the two main types of tissues: meristematic, which is temporary and involved in growth, and permanent tissues like parenchyma, collenchyma, sclerenchyma, xylem, and phloem. The video is aimed at grades 10 to 12 Life Sciences students.
🌱 Meristematic and Permanent Tissues
The speaker discusses the two forms of plant tissues: meristematic and permanent. Meristematic tissues are temporary and involved in the growth of the plant, while permanent tissues last longer and include types like parenchyma, collenchyma, and sclerenchyma. The paragraph also explains the concept of apical and lateral meristems, which are responsible for primary and secondary growth, respectively. Apical meristems contribute to the lengthening of the plant, while lateral meristems, found in the cambium, enable the increase in stem thickness and the formation of bark.
🍃 Epidermis and Specialized Cells
This paragraph delves into the epidermis, a type of permanent tissue that serves a protective function. The epidermis is composed of a single layer of cells and includes the cuticle, a transparent, waxy layer that prevents water loss. Specialized epidermal cells such as stomata and guard cells are introduced, which regulate gas exchange and substance movement in and out of the plant. Root hair cells, another specialized type, increase the surface area for nutrient absorption and water storage.
🌼 Ground Tissues: Parenchyma and Collenchyma
The speaker describes ground tissues, starting with parenchyma, which is abundant and characterized by thin cell walls and intercellular airspaces. Parenchyma provides sponginess, softness, and flexibility to plants and serves as a storage tissue. Chlorenchyma, a type of parenchyma containing chloroplasts, can photosynthesize. Collenchyma is distinguished by its unevenly thickened cell corners, providing support and strength to the plant while maintaining flexibility and the ability to photosynthesize.
🪵 Sclerenchyma and Vascular Tissues
Sclerenchyma is introduced as the thickest of the ground tissues with evenly thickened walls, providing rigidity and strength. It is found in roots, stems, and branches, and includes fibers in wood and bark, as well as sclereids in nuts and stone fruits. The paragraph concludes with a transition to vascular tissues, xylem and phloem, which are specialized for transport within the plant. Xylem is responsible for transporting water and minerals upwards from the roots, while phloem moves sugars in both upward and downward directions.
🌳 Summary of Vascular Tissue Functions
This final paragraph summarizes the functions of the vascular tissues, xylem and phloem. Xylem, composed of elongated, dead cells with thickened walls and large lumens, transports water and minerals one way, from the roots to the shoots. Phloem, with its unique sieve plates and companion cells, facilitates the two-way movement of sugars, from the leaves to the rest of the plant for storage or use. The paragraph ends with a reminder for viewers to subscribe and turn on notifications for regular updates on Life Sciences content.
Mindmap
Keywords
💡Plant Tissues
💡Meristematic Tissue
💡Permanent Tissue
💡Apical Meristem
💡Lateral Meristem
💡Epidermis
💡Stomata
💡Parenchyma
💡Collenchyma
💡Sclerenchyma
💡Vascular Tissues
💡Xylem
💡Phloem
Highlights
Introduction to plant tissues and their identification methods for easier study.
Explanation of the two forms of tissues: meristematic and permanent.
Meristematic tissues' role in growth and their transformation into permanent tissues over time.
Identification of permanent tissues including parenchyma, collenchyma, sclerenchyma, xylem, and phloem.
Description of apical meristems and their function in primary growth.
Lateral meristems' role in secondary growth and cambium function.
Epidermis as the protective tissue with a focus on cuticle and its water retention properties.
Specialized epidermal cells, such as stomata and guard cells, and their function in gas exchange.
Root hair cells' microscopic structure and their importance in nutrient absorption.
Parenchyma as the most abundant tissue with its role in storage and gas exchange.
Chlorenchyma, a specialized parenchyma with chloroplasts for photosynthesis.
Collenchyma's characteristic unevenly thickened cell walls and its role in support and strength.
Sclereid cells in sclerenchyma and their function in providing rigidity and strength.
Xylem's structure and function in unidirectional transport of water and minerals.
Phloem's unique structure with sieve plates and its role in bidirectional transport of sugars.
Differences between vessels and tracheids in xylem and their arrangement.
Companion cells in phloem and their supportive role in nutrient provision.
Conclusion summarizing the importance of understanding plant tissues for academic and practical knowledge.
Transcripts
hi everybody and welcome back to miss
Angus biology class I am Miss angler and
in today's video we are going to look at
plant tissues
um specifically I'm going to show you
how to identify them how to make it
really easy to study for exams because I
know tissues all look the same and
especially plant tissues it's so hard to
tell the difference there's so much to
remember I'm going to make it really
easy I'm also going to break down their
functions that you know what they do
and finally I'm also going to show you
what they look like under a microscope
so that you know in an exam what it
looks like in a diagram form or in a
micrograph now if you are new here don't
forget to give this video a thumbs up
and subscribe and make sure your
notifications are turned on because I
post Life Sciences content for grades 10
to 12.
all right now let's just quickly break
down the plant tissues and then I'm
going to go into more details so tissues
come in two forms they either come as a
meristematic tissue which is tissue that
is temporary and doesn't hang around for
very long in a plant it's where growing
happens whereas permanent tissue is as
the name suggests lasts longer and
technically meristematic tissue becomes
permanent tissue over time and that
particular permanent tissue can be
things like parenchyma collinchyma
sclerenchyma and I'm going to go through
all of those soon now as well as the
vascular tissues which is xylem and
phloem
so let's begin with looking at the Mary
stems now the Mary stems are tissue that
grow and they differentiate into any
kind of tissue and we find them in two
major regions we find them at the tips
of a shoot or the tip of the root which
is what we call apical Mary stems and
then the second location is lateral
which means we actually find it here in
the stem and it is responsible for a
slightly different kind of growth and if
we look over on to the side here apical
Mary stems or the merry stems we find at
the tip they cause primary growth and
they cause the lengthening of the plant
and so what that means is the apical
Mary stems are responsible for plants
growing up towards the Sun but also the
roots growing down towards water and
soil now the lateral Mary stems on the
other hand they are there for secondary
growth and they occur in something
called the cambium when we move on to
the next section when we do plant organs
I'll explain what plant cambium is but
essentially it's this
when you want to make a plant like a
tree or even just a shrub or a bush you
want it stems to become thicker the
cambium is a ring of tissue that allows
you to grow in width in other words one
year may be the width of your stem is
this size but due to lateral Mary stems
two or three years later it could be
this wide and that is because the
lateral merry stems have grown in
thickness the second thing it also does
is it provides bark on trees and that
does make sense because every time you
get a little bit wider you know like the
width of your stem increases you're
going to have to add on a new layer of
bark
Now we move on to the epidermis which is
the first of our permanent tissues now
the epidermis in this picture is grouped
together with a lot of other cells and
tissues I just want to point it out if
we have a look here if we look right at
the surface we see there is a label here
that says cuticle and then it says upper
epidermis and you've actually got a
lower epidermis and then a lower cuticle
down here and so what I'm going to talk
about is those first two the cuticle and
the upper epidermis
so essentially the point of any
epidermis is protection okay so we're
trying to protect everything that is
below it and we also want to make sure
that all the tissues that are sitting
underneath it which is basically
everything down here in this curly
bracket where it says mesophyll we want
to make sure that those cells can do
their job and so the point of
specialized epidermal cells comes into
play here now what is the point of the
epidermis and what is near it or on it
that helps it do its job well we've got
two things here first of all when it
comes to the cuticle which is this
structure over here and if you can't see
what it is it is actually the
see-through layer that's sitting on the
top of a plant a waxy cuticle is
literally made out of wax and it
prevents water loss the other thing
that's really important about the actual
epidermis itself which is this middle
layer over here I'm just going to color
in one of the cells in Black you can see
that is an epidermal cell this whole
thing you'll notice there's only one
cell layer thick there is one next to
each other so here is another one next
to it and there's another one but you'll
notice there aren't any underneath it
there are other cells underneath it and
the reason for that is you want to be
able to get as much sunlight moving from
the waxy cuticle down through the
epidermis and you want to get it into
these other underlying layers and so you
want it to be transparent and that is
also the waxy cuticle being transparent
allowing for sunlight to penetrate into
the lower tissues now some of these
epidermal tissues are specialized for
example if we look at the lower part of
this diagram where it says stoma and
guard cell those are specialized cells
that I'm going to quickly point out
called the stomata
now in preparing for your tests or exams
you may be asked to draw a picture like
this draw any of the cells and label
them this particular diagram is putting
many tissues together but you are going
to have to learn this diagram at some
point because it comes up in the plant
organs section which is after plant
tissues
now as I mentioned you get specialized
epidermis tissue and in particular we
are looking at the stomata the stomata
are the little openings that are on the
underside of the leaf and what you can
see here is what we call a guard cell
and there are two and literally they
guard the openings of your plant and
they make sure that certain substances
can come in and certain substances can
come out and they do that by using their
vacuole and basically their vacuole
fills with water or cell sap or it
empties and that's what opens and closes
the stoma or this opening in the middle
you'll see here is the stoma open and
here is the summer closed by the way the
word stoma should not be confused with
the word stroma
s-t-r-o-m-a the stroma is the filling
inside of a chloroplast
now the final specialized epidermal
tissue is the root hair cell you will
find these cells growing on the surface
of the roots now you can't actually see
these These are microscopic and as you
can see I mean this is an example
there's the sides of the soil particle
and there's the size of the root here
it's very very very small you can't
actually see these but you'll see that
it's got this really long elongated
um structure to it and in actual fact
what it's doing is it's pushing it's um
vacuole down into the elongated part so
you can actually see here is a normal
size vacuole along size so there it is
if I just do a little upline whereas
this particular one goes all the way
down and then it comes all the way
around you can see it's very very large
and so what they've done is they've
elongated their vacuole down so that
they can make this long root hair now
why do we do this well root hair cells
have two functions
um the reason that they have these two
functions is to improve the surface area
of the plant because you want to absorb
as much nutrients from the soil as
possible and the second thing is you
want a nice large vacuole not just to
help with the root hair but to help
store the water or the minerals that are
actually coming in and then once they're
in the plant then you can determine
where they go
we're now going to move on to the next
kind of permanent tissue which is our
ground tissues starting with parenchyma
or parenchyma depending on how your
teacher says it and these are the most
abundant tissues in Plants we see three
different kinds and I'm going to go
through how to identify them and their
functions now starting off with
parenchyma looking at parenchyma we need
to be able to see it in a diagram and in
a micrograph and we need to look for two
things when we identify the first thing
is it must have a thin cell wall which
we can actually see very clearly in the
micrograph over here it's a very thin
cell wall and also we're looking for
intercellular airspaces which again you
can actually see in the micrograph
really clearly it's these little spaces
in between and if I color them in there
is an intercellular airspace there's
another and there's another if we look
at the diagram often what you see is
this kind of picture over here and it
looks like they're irregularly shaped so
sort of round rectangular shaped cells
and it links back to their purpose their
shape remember shape equals function and
if we look at their functions it
actually makes sense why they look the
way they do they are what we call the
packaging tissue which means that they
give the body like sponginess and
softness and flexibility and so being
these like circular shapes does that and
having spaces in between them makes them
more spongy they're also where we store
things you'll notice they look quite
empty I mean if you look at the
micrograph there's nothing really inside
of here and that's because they need a
lot of space to store stuff now the
intracellular airspaces allow for
gaseous exchange because it's where
gases can can literally Exchange in that
empty space and it also allows for
meiosis because again you need an empty
space for water to move through and so
that's what parenchyma or parenchyma
does for plants
now a special mention for parenchyma
that has chloroplasts in it because I
want to point out regular parenchyma
doesn't have any chloroplasts in it but
a special mention for parenchyma who
does we call them chlorine chymer and
literally they've changed their name
because their normal parenchyma but now
they've got chloroplasts inside of them
which means they can photosynthesize and
this often is the parenchymen you can
see on the surface of a stem that's what
makes the stem green and fleshy
the next tissue is Colin kymer and um
collenchymers sometimes is confused with
parenchyma because they look very very
similar let me show you how to tell the
difference between them so when we are
trying to identify them we're looking
for two things number one we're going to
look for these thickened corners and if
you have a look down at this micrograph
you can see here the corners are
unevenly thickened in other words if you
even compare it to this one over here
that's a very very very thick corner
now other than the thickened Corners
you'll also notice that the corners are
definitely unevenly thickened you'll
notice that one side of the cell will be
really really thin and then maybe
another side of the cell will be much
much thinner so you're looking for that
uneven look
um and that's pretty much the easiest
way to identify them and if you look at
our diagram at the top here if they gave
this to you in an exam what you're
looking for and you can see it quite
clearly here is it seems as though the
cell wall doesn't sit perfectly around
the cytoplasm in the sentence because
it's so unevenly thickened so you're
looking for that unevenness around the
cytoplasm on the inside now this
thickness has a function because
remember shape is function
and so if we look at our functions in
Colon Kyla we can see a couple of things
one we can see that it provides support
and strength
now Colin Khan is able to do this
because its walls have been thickened
with cellulose and pectin and now these
walls are thicker but they still have
flexibility so it means that we can
still have like soft bendy green stems
the stems haven't made the transition
into a woody stem just yet and most
importantly they are still green and
they'll be able to photosynthesize which
means that Colin kymer does have
um oroplas in it as well
our final ground tissue is going to be
our sclerenchyma now sclerenchyma is the
thickest of the tissues sometimes again
this one is a little bit confused with
Colin kymer but you've got to look out
for one main important detail and that
is when we are trying to identify them
they have evenly thickened walls and if
you look alongside here at our
micrograph you can see that the walls
are much more evenly thickened all the
way around you'll notice that it's not
like slightly thinner on one side and
then slightly thicker on the other as we
saw in Colin Karma it's evenly thickened
it's even more clearly seen in the
diagram here where the thickened walls
make more of like a geometric and
consistent or uniform pattern now
sclerenchyma's functions are divided
into two depending on where you find
them the main function of sclerenchyma
is to provide rigidity and strength
which means that you want to keep things
upright and stable we find this in a lot
part of our roots and our stems
and our branches and this is where we
find wood and scaram Karma is actually
divided into two if it is a sclerenchyma
that's a fiber we are going to see it in
wood and bark of a tree and that's what
you can see alongside it these are what
our fibers look like when you cut them
in half and you can see on the inside
clarids on the other hand are another
kind of sclerenchyma and these scleros
are found in nuts or stone fruit so the
shell of a nut or the pit of a stone
fruit on the center and they look a
little bit like the one that we have
alongside but if I were to sketch it for
you essentially the main difference if
we draw them is sitting on the inside if
that is the outside of the cell wall it
seems like they have these like pinched
in centers that have these like little
arms that stick out
and um they seem to look like their
cytoplasm has like fallen in on itself
like it doesn't have a cell wall or a
cell membrane anymore and the reason for
that is sclerenchana out of all the uh
ground tissues is dead all the other
tissues are living Scar and climate most
importantly is non-living or should I
say it's rather dead it was alive and
now it has died
now let's move into the final set of
tissues which is the vascular tissues
these are the transporting tissues that
we see in plants and they are very
specialized in their structure and they
are xylem and phloem now let's run
through xylem first of all you may be
familiar with xylem you may have learned
it in previous grades it transports
water and it's got a very specific
structure if we focus in on the main
structure points of xylem it has
elongated cells which means they're like
long and thin a large Lumen literally
means that the whole or the opening is
quite large in other words it's quite
big so that's a large Lumen versus a
smaller lumen they're dead and empty
um and so there's nothing inside of them
there is no cytoplasm there is no
organelles and that would get in the way
of transporting water their cell walls
are thickened with lignin and they do
that because of the water pressure the
water is really like strong so it pushes
up against the wall of the xylem and you
need to keep it um stable and lastly
they have pits for lateral water
movement and if you have a look
alongside on the diagram
you can actually see some of the pits
which are these little openings and
they've actually labeled them on the
diagram as well those are the pits and
that allows for lateral water movement
so you can move from one xylem vessel to
the next so the overall function of
xylem is simply to transport water and
minerals in One Direction this is
important only in one from Niche from
the roots to the shoots and xylem
vessels can come in two different
structures
um basically xylem comes in two
different shapes if you will and we call
them either vessels or tracheots vessels
are round and elongated whereas trackids
are spindle and what spindle means is
that they sort of like taper off at the
end and so if I were to draw that for
you so you can see what I mean a vessel
would be like a round shape like that
like a long tube right like a cylinder
whereas a tracheid would um be long as
well
but the ends kind of go pinch in they
like taper off like that so that's a
slight difference between the two
and so that's why I call them round or
spindle and then the way they are
arranged so here they say end to end
which is what our vessels are so what
that means is that wherever one vessel
ends another one is stacked on top of it
like that whereas overlapped it means
that the tracheids the nature of their
shape where it's pointy at the end it
means they actually need to be
overlapped so they sort of like
sit like this on top of each other so
they overlap and that's how you can tell
the difference between the two
now let's look on to phloem which is
like the sister to xylem and they do
have a lot in common in terms of their
physical appearance but there are some
very defining structural things that I
want you to look out for something that
phloem does share with xylem is that it
is also arranged end to end so it's
stacked on top of each other and you can
see that um quite nicely actually
alongside here you can see the cells
stacked on top of each other so here is
one stack and here is the next and so
those are stacked onto each other and
that's what it means to be overlapped
but then they have the structure which
makes them very unique which is this
structure over here called the sieve
plate the purpose of the silver plate
like any sieve is to filter out make
sure that there's any like large pieces
of sugar that it is flattened out and so
that it can move more freely because it
can great it can get quite like goopy
and sugary like syrup so you want to
keep it flowing quite well and the last
thing which isn't in this diagram here
but but alongside
um phloem cells they have companion
cells which are essentially
cells sitting alongside
um these are just regular like
parenchyma cells they're not necessarily
any companion cells but they could
technically be comparing companion cells
as well perhaps but essentially what
they do is these companion cells sit
alongside our phloem cells and they
provide phloem with all the nutrients it
needs to survive all of the mitochondria
and energy because you don't want any
other organelles in the way you want to
keep the phloem empty so you don't want
any organelles there so you put it in a
little Companion now as to the functions
of our phloem when we speak about the
function of phloem I think we already
know it transports sugars and it's a
two-way movement which means that sugars
are going to go from the bottom up so
from the roots to the shoots but they
must also be able to go from the leaves
where they're ultimately made down to
the roots to be stored later so that's
also another defining difference between
Xylo and phloem is the move movement of
substances
and that's it for today's video I hope
you've enjoyed it make sure you are
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as other grade 10 topics bye
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