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Plant tissues
The root system: anchors the plant and provides nutrition
...

-

Dicots: taproot system; primary root (nutrient storage organ) and less
prominent lateral roots

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Monocots: fibrous root system; numerous thin leaves

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Adventitious roots: rise above ground

The shoot system:
-

Leaves: site of photosynthesis, consist of a thin flat structure (blade) and
attached to the step by a petiole (node), there is a lateral bud
...
The region between 2 nodes is called an internode
...


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Plant cells: contain chloroplasts, vacuoles, cell walls
...
Edges fuse with the
old cell wall and form the primary cell wall of the daughter cells
...
A pectic
substance forms the middle lamella
...

Cells with a waterproofed cell wall have pits for material transport
...

Endodermis contain suberin (waterproof)
Cortex: nutrient storage
Pith: stores carbohydrate reserves
Perocycle: contributes to secondary growth
Xylem: transports water in a plant
Phloem: transport sugars in a plant

Cross section of a monocot root structure

Cross section of a dicot root structure



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Stem structure:

Cross- section of a monocot stem structure

Cross- section of a dicot stem structure
Secondary growth:
This is growth in diameter, produced by vascular and cork cambia
...


-

Cork cambium: produces new protective cells in the outward direction,
forming cork which contains suberin (cork and cork cambium= periderm)

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Simple plant tissues
(Composed of one type of cell)
Tissue

Function

Cell shape

Distribution

PARENCHYMA

Packing tissue,

Living, cell wall has

Found in

supportive tissue,

cellulose, toughly

pith of

metabolically active,

spherical/elongated

stems and

allow gas exchange,

outer cortex

food storage, apoplast
pathway

MODIFIED

Secretes cutin which

Living, cell wall has

Found in

PARENCHYMA

forms a cuticle which

cellulose and cutin
...
g
...
Their

are more regular and

hair like extensions

plant body

rectangular
...

Mechanical protective
function and trap and
kill insects
...
g
...

e
...
mesophyll

Carry out

Living, cell wall has

Found in

cells

photosynthesis

cellulose
...
There column-shaped and spongy layer of the
are two layers of

are roughly spherical,

mesophyll; palisade

plant body
...


(photosynthesis) and
spongy (gas
exchange), store
starch
e
...
endodermal

Each cell has a

Living, cell wall has

Found

cells

caspariam strip

cellulose and suberin,

surrounding

(suberin)
...


the vascular

barrier between cortex

tissue in

and xylem
...


e
...
pericycle

Have meristematic

Living, cell wall has

Found

cells

activity, contribute to

cellulose, roughly spherical

between

secondary growth
...


central
vascular
tissue and
endodermis
in roots
...


SCLERENCHYMA Support and

Dead with mature,

Found in

FIBRES

cellulose (secondary –

pericycle,

lignin – red) elongated and

capping the

polygonal with tapering

vascular

interlocking ends

bundles of

mechanical strength

dicots,
below
epidermis,
in xylem +
phloem
...
Thick

Found in

cell wall- cellulose (2° -

cortex, pith,

lignin) with interruptions

phloem,

(pits – no lignin)
...



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Complex plant tissues
(More than one type of cells)
Tissue

Function

Cell shape

XYLEM

Conducts

Dead, cell wall has cellulose and Found in the

water

Distribution

and lignin
...


salts up to
the

vascular
system
...


interlocking ends

system

of

ferns

and

conifers
...


Dead

with

empty

cellulose

lignified
...
5 types of cells
•

Sieve

tube

translocation

Vascular

elements: system
of

organic

food, cytoplasm – thread
like
•

Companion cells: survival
and functioning of sieve
tube

elements,

active

cytoplasm
•

Parenchyma

•

Fibres

•

Sclereids

First phloem formed on elongation – protophloem
When it mature – metaphloem

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