PLANT TISSUES | EASY to UNDERSTAND

Summary

In 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

00:00

🌿 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.

05:01

🌱 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.

10:02

🍃 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.

15:03

🌼 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.

20:03

🪵 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.

Keywords

💡Plant Tissues

Plant tissues are the fundamental structural and functional units in plants, analogous to organs in animals. In the video, the main theme revolves around identifying and understanding the different types of plant tissues, their functions, and their appearances under a microscope. The script mentions various types of tissues, such as meristematic and permanent tissues, emphasizing their roles in plant growth and structure.

💡Meristematic Tissue

Meristematic tissue is a type of plant tissue that is involved in the growth of the plant. It is characterized by its temporary nature and its role in areas where active cell division occurs. In the script, the teacher explains that meristematic tissues are responsible for primary growth, such as the elongation of the plant towards the sun and the growth of roots towards water and soil.

💡Permanent Tissue

Permanent tissues are those that last longer within the plant and are derived from meristematic tissues over time. The script breaks down permanent tissues into several categories, including parenchyma, collenchyma, sclerenchyma, and vascular tissues like xylem and phloem. These tissues perform various functions, such as providing support, storage, and transport within the plant.

💡Apical Meristem

Apical meristem refers to the growth tissue found at the tips of shoots and roots. In the video script, the teacher describes how apical meristems are responsible for primary growth, which is the increase in length of the plant. This is a critical concept for understanding how plants grow upwards and downwards.

💡Lateral Meristem

Lateral meristem is a type of plant tissue associated with secondary growth, which is the increase in girth or thickness of the plant. The script mentions the cambium as an example of lateral meristem, which allows for the widening of stems and the formation of bark in trees.

💡Epidermis

The epidermis is the outermost layer of cells that covers the plant and serves a protective role. In the script, the teacher explains that the epidermis, along with the cuticle, prevents water loss and allows sunlight to penetrate to the underlying tissues. Specialized epidermal cells, such as stomata and root hair cells, are also discussed in relation to their specific functions.

💡Stomata

Stomata are specialized structures in the epidermis that allow for gas exchange and transpiration. The script describes stomata as openings guarded by two specialized cells called guard cells, which regulate the movement of substances in and out of the plant. This is an important concept for understanding plant respiration and water regulation.

💡Parenchyma

Parenchyma is a type of ground tissue that is characterized by its thin cell walls and intercellular airspaces. The script explains that parenchyma provides sponginess, softness, and flexibility to the plant, and is involved in storage and gaseous exchange. Chlorenchyma, a subtype with chloroplasts, is also mentioned for its role in photosynthesis.

💡Collenchyma

Collenchyma is another type of ground tissue that provides support and strength to the plant. The script distinguishes collenchyma by its unevenly thickened cell corners, which give it flexibility while maintaining structural integrity. This tissue is important for the support of green, non-woody stems.

💡Sclerenchyma

Sclerenchyma is a ground tissue with thickened walls that provide rigidity and strength. The script differentiates sclerenchyma by its evenly thickened walls and its role in forming wood and bark in trees. It is also mentioned that sclerenchyma fibers and sclereids, two subtypes, are involved in the structure of nuts and stone fruits.

💡Vascular Tissues

Vascular tissues are specialized for the transport of substances within the plant. The script discusses xylem and phloem as the two main types of vascular tissues. Xylem is responsible for the unidirectional transport of water and minerals from roots to shoots, while phloem transports sugars in a two-way movement between roots and leaves.

💡Xylem

Xylem is a vascular tissue that transports water and minerals throughout the plant. The script describes xylem as having elongated, dead cells with large lumens and thickened walls reinforced with lignin. This structure allows for efficient water transport from the roots to the rest of the plant.

💡Phloem

Phloem is the vascular tissue responsible for the transport of sugars, primarily produced during photosynthesis in the leaves. The script explains that phloem has a unique structure with sieve plates that facilitate the movement of sugars and companion cells that support the phloem's metabolic needs. The bidirectional transport of sugars is a key function of 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

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