1. UNIT 4: PLANT TISSUE

2. MERISTEMATIC TISSUE
A flowering plant has the ability to grow its entire life because it possesses meristematic (embryonic) tissue.
The apical meristem are located at or near the tips of stems and roots, where they increase the length of their structures by means of mitosis.
This increase in length is called primary growth.
Monocots also have an intercalary meristem, this allows them to regrow lost parts. (It is found between mature tissues). EXAMPLE: GRASS CUT - GROW

3. Organization of a plant body
MERISTEMATIC TISSUE AT TIP OF STEM
MERISTEMATIC TISSUE AT TIP OF ROOTS

4. SPECIALIZED PRIMARY TISSUES:
APICAL MERISTEM
Produces three types of meristems, and these develop into the three types of specialized primary tissues in the body of the plant:
SPECIALIZED PRIMARY TISSUES: 
Protoderm gives rise to the epidermis
Ground meristem produced ground tissue
Procambium produces vascular tissue

5. FUNCTIONS OF SPECIALIZED TISSUES
Epidermal tissue: forms the outer protective covering of a plant.
Ground tissue fills the interior of a plant.
Vascular tissue transports water and nutrients in a plant and provides support.

6. EPIDERMAL TISSUE

7. EPIDERMAL TISSUE
Single layer of closely packed, flat, brick shaped cells, with a large vacuole.
The aerial parts of the plant are covered with a cuticle.
Functions:
- Cuticle minimizes water loss (because it has cutin)
- Protects the plant against bacteria.
Longitudinal section
Cross section

8. Leaf contain upper and lower epidermal cells

9. SPECIALIZE EPIDERMAL CELLS
TRICHOMES
ROOT HAIR
TRICHOMES
STOMA OF LEAF
CORK OF OLDER STEMS
ROOT HAIRS
STOMATA
CORK CELLS

10. ROOT HAIRS They are specialized epidermal cells of roots.
Unicellular outgrowth of the epidermal cell.
Functions:
Increase the surface area of the root for absorption of water and minerals.
Anchor the plant.

11. TRICHOMES Specialized epidermal cell of stems and leaves.
Multicellular outgrowths of the epidermis of stems and leaves.
Functions:
Protect the plant from sun
Conserve moisture.
Protect plant from herbivores, produce toxic substance.
CUTICLE
MULTICELLULAR

12. STOMATA
Specialized epidermal cells called guard cells, which are bean shaped, enclose an opening called the stoma or pore.
The guard cells contain a nucleus and chloroplasts.
It has a thick inner membrane and a thin outer membrane.
Woody plants have lenticels.
FUNCTIONS:
Transpiration
Gaseous exchange take place through the stomata.
Thick inner membrane
Thin outer membrane

13. CLOSED- NIGHT
OPEN - DAY

14. PARENCHYMA COLLENCHYMA SCLERENCHYMA
GROUND TISSUE
PARENCHYMA
COLLENCHYMA
SCLERENCHYMA

15. GROUND TISSUES

16. PARENCHYMA TISSUE FUNCTIONS: Occur in roots, stems and leaves.
If they have chloroplasts – photosynthesis.
If they have leucoplasts – they store products of photosynthesis.
They can divide to form more specialized cells
Occur in roots, stems and leaves.
Spherical, loosely packed, big, thin-walled cells with large vacuoles.
Intercellular airspaces between cells.

17. INTERCELLULAR AIR SPACES
PARENCHYMA CELLS

18. COLLENCHYMA TISSUE FUNCTIONS:
Mechanical strengthening and support to plant organs
It is composed of unevenly thickened primary walls with additional cellulose and pectin deposits especially in the corners.
Found just beneath the epidermis of young stems.
The cells are slightly elongated, tightly packed and overlap each other.

20. SCLERENCHYMA TISSUE
Cell walls have been thickened by impregnation with lignin.
The cell wall is evenly thickened and forms a waterproof barrier impermeable to water.
In the cell walls are pit canals that serve as channels between cells and to the outside world.
The lumen is small.
Two types of Sclerenchyma:
Stone cells and fibers
FUNCTIONS:
Strengthening, support and protection.
Found in shell of nuts and hard parts of fruits
Fibers give rigidity and flexibility to the plant.

22. Vascular tissue
XYLEM
PHLOEM

23. XYLEM
Contains 2 types of conducting cells: tracheids and vessel elements (VE).
Both cells are hollow and non-living but the VE is larger and has perforated plates in their end walls and are arranged to form a continuous vessel.
Tracheids have tapered ends with pits.
It also has other tissue: Xylem fibers, and Xylem parenchyma.
FUNCTION: Transports water and minerals
from the roots to the leaves.
Support and strengthening.

24. XYLEM

25. PHLOEM Consist of sieve-tubes and companion cells.
The sieve-tubes form a continuous tube, they have cytoplasm but no nuclei.
They have sieve plates between cells.
The companion cell has a nucleus that controls both cells because they are connected by plasmodesmata.
It also has other tissue: Phloem fibers and phloem parenchyma
FUNCTIONS: Transports sucrose and other
organic substances, including
hormones, from the leaves to the
roots.
Support and strengthening.

27. METHODS TO STUDY CELLS
The microscope is an instrument designed to observe objects too small to be seen with the naked eye.
The human eye cannot distinguish objects much smaller than 0.1mm.
The microscope act as an extension of the eye, allowing one to see smaller objects.

29. ELECTRON MICROSCOPE
The electron microscope was developed in the late 1940’s and soon used in the study of cells.
Much more detail can be seen under an electron microscope. It can magnify parts of cells at least times.

30. SCANNING ELECTRON MICROGRAPH
TRANSMISSION ELECTRON MICROGRAPH