it is a presentation about the plant structure and its function-24 slides

3. – They are the most abundant kind of plant cell.
– They are found throughout the tissues of a plant.
– These spherical cells have thin, flexible cell walls.
– Most parenchyma cells usually have a large central
vacuole, which sometimes contains a fluid called sap.
– The fleshy parts of most fruits are made up mostly of parenchyma cells.
– When the cells contain chlorophyll, they can carry photosynthesis and are
called chlorenchyma.
– Functions:
food production (photosynthesis) so it can contain
numerous chloroplasts -- storage of water and nutrients --healing.

4. – They are long cells with unevenly thickened cell walls.
– These cells are arranged in tube-like strands or cylinders
that provide support for surrounding tissue.
– There usually grouped in strands.
– Celery stalks contain a great amount of collenchyma cells.
Function:
It allows the cells to grow. The walls of collenchyma cells can stretch as the cells
grow while providing strength and support.
Can carry photosynthesis if chlorophyll is present.

5. – The walls of sclerenchyma cells are very thick and rigid.
– At maturity, these cells often die.
– Although their cytoplasm disintegrates, their strong, thick cell walls
remain and provide support for the plant.
– Present in the vascular bundles in xylem and
phloem in stem, roots and in the veins of leaves. present
Also, present in the hard seed coat covering.
Cells are dead but are connected through the pits,
pits are places where lignin is absent.

6. Kinds of Sclerenchyma cells:
1) Fibers:
Fibers are long, thin cells that form strands.
They provide support and strength for the plant and are the source of
fibers used for making linen and rope.
A type of fiber is associated with vascular tissue
2) Sclerids:
Sclerids are irregularly shaped and usually found in clusters. They are
the gritty texture of pears and a major component of the pits found in
peaches and other fruits.

8. Dermal Tissue System:
– It forms the outside covering of plants (epidermis).
– It is made of parenchyma cells.
– The outer epidermal wall is often covered by a waxy layer called
Cuticle, which prevents water loss.
– Some epidermal cells of the roots develop
hair-like extentions (Trichomes) that increase
water absorption.
– In some cases, trichomes are glandular and
secrete toxic substances that help protect the plant from predators.

9. Dermal Tissue System:
– It has Stomata (openings in the leaf and system epidermis) which regulate
the passage of gases and moisture
into and out of the plant.
– In woody stems and roots, the epidermis
is replaced by dead cork cells.

10. Ground Tissues:
Ground tissue makes up much of the interior of a plant and carries out basic
metabolic functions. Ground tissue in stems provides support and may store
food or water. Ground tissues in roots may also store food.
Function: metabolism, storage, and support activities
a) the ground tissue of the leaf (called mesophyll) uses the energy in sunlight
to synthesize sugars in a process known as photosynthesis
b) the ground tissue of the stem (called pith and cortex) develops support cells
to hold the young plant upright
c) the ground tissue of the root (also called cortex) often stores energy- rich
carbohydrates

12. Vascular Tissues:
– Vascular tissue runs through the ground tissue inside a plant. Your body was able
to grow from a single cell to perhaps 100 trillion cells because, 21 days after
fertilization, a tiny heart began to pump blood throughout your tiny self – and it
hasn’t stopped since. The blood it pumps carries water, oxygen and nutrients to
each one of your trillions of cells, and removes CO2 and other wastes.
– Of course plants don’t have hearts, but they do have vessels that transport
water, minerals, and nutrients through the plant. These vessels are the vascular
tissue, and consist of xylem and phloem. Xylem and phloem are packaged
together in bundles.
– Function: the transport of water and dissolved substances inside the plant

13. – Tracheids and vessel elements are the conducting cells of the xylem. These cells
die when they mature but their cell walls remain.
– Tracheids are tubular cells tapered at each end. The cell walls between adjoining
tracheid have pits through which water and dissolved minerals flow.
– Vessel elements are tubular cells that transport water throughout the plant.
They are wider and shorter than tracheids and have openings in their
end walls.
– Anthophyte vessel elements are thought to transport water more efficiently than
tracheids because water can flow freely from vessel element to vessel element
through the openings in their end walls.

14. – Phloem is made up of tubular cells joined end to end.
– It is similar to xylem because phloem also has long cylindrical cells. However these
cells, called sieve tube members are alive at maturity.
– They contain cytoplasm but do not have a nucleus or ribosomes.
– Next to each sieve tube member is a companion cell. Companion cells are nucleated
cells that help with the transport of sugars and other organic compounds through the
sieve tubes of the phloem.
– The end walls between two sieve tube members are
called sieve plates.
– The sieve plate have large pores that allow sugar and
organic compounds to move from sieve tube member to
sieve tube member.
Phloem can transport materials from the roots to
the leaves also.

15. – a) the xylem carries water and dissolved ions from the roots to
stems and leaves
– b) the phloem carries dissolved sugars from the leaves to all
other parts of the plant

16. – Summary
• The three types of plant cells are found in each of the major types of plant
tissues: dermal, ground, and vascular tissues.
• Dermal tissue covers the outside of a plant in a single layer of cells called the
epidermis. It mediates most of the interactions between a plant and its
environment.
• Ground tissue makes up most of the interior of a plant. It carries out basic
metabolic functions and stores food and water.
• Vascular tissue runs through the ground tissue inside a plant. It consists of
bundles of xylem and phloem, which transport food, water and minerals
throughout the plant.

18. Meristematic tissues
Apical Meristems Lateral Meristems
Vascular Cambium Cork Cambium
Intercalary Meristems

19. Plant growth originates mainly in Meritesm, regions where cells continuously
divide.
1) Apical meritesm:
It is located at the tips of stems and roots.
Most of plants grow in length through apical meritesm.

20. 2) Intercalary Meritesm:
It Is located above the bases of leaves and stems.
Some monocots grow in length through
Intercalary meritesm.
It allows grass leaves to quickly regrow after
being grazed or mowed.
Gymnosperms and most dicots also have Lateral Meritesms, which allows
stems and roots to increase in diameter. It is located near the outside of
stems and roots. It has two types:
1) Vascular Cambium
2) Cork Cambium

21. 1) Vascular Cambium:
It is located between xylem and phloem.
It produces additional vascular tissues.
2) Cork Cambium:
• It is located outside the phloem.
• It produces cork cells which replace
epidermis in woody stems and roots.
• Cork cells are dead cells that provide
protection and prevent water loss.
So, the tree grow taller and wider over time.

22. Note:
– A third type of lateral meristem is found in
grasses, corn, and other monocots. This
meristem adds cells that lengthen the part of the
stem between the leaves. These plants do not
have a vascular or a cork cambium.

24. Group 2
1-Salah Ayman
2-Mahmoud Ibrahim
3-Mina Magdy
4-Kiroulls Youssef
5-Islam Essam