1. Plant Tissue
Discussant:
Ms. Janette D. Japones

2. Plant Organs The 3 primary organs found in plants are:
Leaves
Stems
Roots
Since flowers are thought to have evolved from leaves, they are called “reproductive structures”.
Leaves, stems, roots, and flowers are all made up of various tissues.

3. What is plant tissue?
Is an organization of mature cells of one or more types that have common origin to perform a particular function.
Develops by means of differentiation.

4. Tissue
a group of similar cells organized into a structural and functional unit.

5. Tissue system
a tissue or group of tissues organized into a structural and functional unit, larger units of the plant body.

6. Meristematic Tissues
Meristems are places in plants where cell division is occurring.
During cell division, one cell becomes two cells. Each new cell can also divide.

7. Meristematic Tissues
In this class we will discuss three kinds of meristems:
Apical Meristems
Lateral Meristems
Intercalary Meristems

8. Microscopic View of an Apical Meristem
Apical Meristems
In plants belonging to the DICOT class, apical meristems are located in BOTH the shoot tips and root tips. A shoot is simply a young, leaf-bearing stem.
In plants belonging to the MONOCOT class, apical meristems are located ONLY in the root tips.
Microscopic View of an Apical Meristem

9. Apical Meristem in a Root Tip
Apical Meristems
Apical meristems cause PRIMARY GROWTH.
As cells in apical meristems divide and elongate, shoot tips and root tips grow longer. This increase in length is called primary growth.
Apical Meristem in a Root Tip

10. Apical Meristems
Primary growth of shoots and roots occurs as the cells of the apical meristem divide and elongate.

11. Apical Meristems A bud is a dormant apical meristem.
When conditions are favorable for growth, buds “break” and begin pushing out new growth.
Bud Break

12. Buds Buds come in 3 basic types: Vegetative-produce stems and leaves.
Flower-produce only flowers.
Mixed-produce stems/leaves and flowers.

13. Mixed buds of Amelanchier x grandiflora

14. Mixed Buds of Cornus alternifolia1 2 3 4

15. Pussy Willow
Pussy Willow is a plant which bears separate vegetative and flower buds. In the image to the left you can see vegetative buds producing green leaves and flower buds producing male flowers (the species is dioecious). Also, note that the two different types of buds are indistinguishable from one another.
vegetative bud
flower bud

16. Lantanaphyllum Viburnum
vegetative bud
flower bud
Viburnum x rhytidophylloides, Lantanaphyllum Viburnum, also bears separate vegetative and flower buds. However, the two types of buds are distinctly different from one another in appearance.

17. Lateral Meristems cause an increase in stem diameter
In addition to the apical meristems located in the shoot and root tips, plants in the DICOT class have lateral meristems.
Lateral meristems cause SECONDARY GROWTH.
Secondary growth causes stems and roots to grow larger in diameter.
Lateral Meristems cause an increase in stem diameter

18. Lateral Meristems
Think of a lateral meristem as being a cylinder, several cell layers thick, of actively dividing cells.

19. Lateral Meristems MONOCOTS do not have lateral meristems.
Lateral meristems come in two basic types:
Vascular cambium; meristematic tissue located between the xylem and phloem. The vascular cambium makes new xylem and phloem cells.
Cork cambium; meristematic tissue located just below the bark in woody dicot stems. The cork cambium makes new bark cells.

20. Lateral Meristems Phloem Vascular Cambium Xylem (Wood)
Cross Section of a Woody Dicot Stem

21. Lateral Meristems Cork (Bark) Cork Cambium Vascular Cambium
Woody Dicot Stem

22. Intercalary Meristems
In addition to the apical meristems located in their root tips, plants in the MONOCOT class have special meristems called intercalary meristems.
Intercalary meristems are located on monocots where the leaf bases connect to the stem of the plant.

23. Intercalary Meristems
Monocots, like grasses, have intercalary meristems which allow the leaves to grow back after mowing.

24. Group 1.
Make a short essay.

25. Why do we need to study the plant tissue?

26. Group 2.
Make a short poem showing the importance of plant tissue.

27. Thank you!! 
Discussant:
Ms. Janette D. Japones
BEED 4A