Monocotyledons vs dicotyledons 9

سكشن عملي
خاص بطلبة كلية الصيدلة والتصنيع الدوائي
جامعة سوهاج
وفق الله جميع الطلاب الي ما يحب ويرضى
ادعوا لنا بالتوفيق

1. Plant kingdom

2. Monocot vs. Dicot
•Angiosperms (flowering plants) are divided
into monocots and dicots
•As the zygote grows into the embryo, the first
leaves of the young plant develop and are called
cotyledons (seed or embryonic leaves)
•Monocots have one cotyledon (corn).
•Dicots have two cotyledons (bean).
•There are several differences between
monocots and dicots

3. Difference 1:
•Number of seed leaves (or cotyledon)
Monocots vs Dicots
One seed leaf Two seed

4. Monocot vs. Dicot
•Number of cotyledons: one vs. two

5. •Leaf venation pattern:
•Monocot is parallel
•Dicot is net pattern
Difference 2:
Monocots and dicots differ in the arrangement of veins,
the vascular tissue of leaves

6. Leaves
Monocot versus Dicots
Base of a Monocot
Leaf: Note the Sheath
which connects the
Blade to the Stem
Typical Dicot Leaf
with Reticulate
(Net) Venation

7. Which is which?
B is __________
A is _____________

8. Cross section of a
dicot leaf
Cross section of a
monocot leaf

9. Monocot leaves Dicot. Leaves



not differentiated into
palisade and spongy
cells.

Differentiated into
palisade and spongy
parenchyma
1- Mesophyll
V.B. closed (don’t
contain cambium)
V.B. open 2- Vascular
tissues
The bundle sheath may
be parenchyma or
sclerenchyma or thick
walled parenchyma.
The bundle sheath
parenchymatous
fibers (above and below
the bundles).
Collenchyma cells
located below the upper
and lower epidermis
opposite to the bundles.
3- Supporting
tissues

10. •Stem types:

–Monocot: Herbaceous



–Dicot: herbaceous or woody
Difference 3:

11. •Vascular Bundles (transport vessels in plants)
Monocot vs. Dicot
Scattered throughout Arranged in ring
stem in stem

12. Monocot. Stem Dicot. Stem






1- V.B. closed (don’t contain
cambium)
1- V.B. open
2- V.B. large number, scattered
irregularly through the ground
tissue.
2- V.B. arranged in a single ring
arround a central region called
pith
3- Cortex, M.R.s, pith, pericycle,
endodermis are indistinguishable
3- Cortex, M.R.s, pith, pericycle,
endodermis are well marked
4- hypodermis mostly
sclerenchymatous
4- hypodermis almost
collenchymatous

13. Phloem Xylem
Sclerenchyma
(fiber cells)
Ground tissue
connecting
pith to cortex
Pith
Cortex
1 mm
Epidermis
Vascular
bundle
Cross section of stem with vascular bundles forming
a ring (typical of eudicots)
(a)
Key
to labels
Dermal
Ground
Vascular
Cross section of stem with scattered vascular bundles
(typical of monocots)
(b)
1 mm
Epidermis
Vascular
bundles
Ground
tissue
•In most monocot stems, the vascular bundles are scattered
throughout the ground tissue, rather than forming a ring
Plant Growth - Stems

14. Stems
Monocot versus Dicot
Cross Section of a
typical Dicot Stem
Cross Section of
Corn which is a
typical Monocot

16. Taproots: Fibrous roots:
Typical of dicots,
primary root forms
and small branch
roots grow from it
In monocots mostly,
primary root dies,
replaced by new
roots from stem
Difference 4:

17. Roots – Structure and Development
1250 µm
Epidermis
Primary phloem
Primary xylem
Pith
Monocot

Eudicot

Endodermis
Cortex
Epidermis
Primary xylem
Pericycle
Primary phloem
48 µm
385 µm
8 µm
Endodermis
Location of
Casparian strip
Endodermis
Location of
Casparian strip
Cortex
Pericycle

18. Cross
section of
a dicot root
Cross section
of a monocot
root

20. Casparian strips
Are deposited on
the radial and
inner tangential
walls.
Casparian strips
Are deposited on
radial walls only
Endodermis
numerous 2-8
The number of
xylem/phloem
strands
Always present Very narrow or
absent
Pith
Dicot root Monocot root

21. Difference 5:
•Flower Parts
Monocot vs. Dicot
Multiples of 3 Multiples of 4 or 5

22. Monocot vs. Dicot
•Flower parts:

•Monocot: in groups of three

•Dicot: in groups of four or five

24. Comparing Monocots vs. Dicots
FEATURE MONOCOTS DICOTS
Cotyledons 1 2
Leaf venation parallel Net pattern
Root system Fibrous Tap
Number of
floral parts
In 3’s In 4’s or 5’s
Vascular
bundle position
Scattered Arranged in a
circle
Woody or
herbaceous
Herbaceous Either