1. Plant Tissues and Organs

2. Fig. 38.6

3. REMEMBER:
“STEM CELLS IS TO ANIMAL CELLS MERISTEMS IS TO PLANT CELLS”

4. MERISTEM

5. MERISTEM a. Terminal meristems- ends of stems, branches and roots
Tissues of most plants consisting of undifferentiated cells (meristematic cells), found in zones of the plant where growth can take place (tips of the roots and stems). The meristematic cells give rise to various organs of the plant:
a. Terminal meristems- ends of stems, branches and roots
b. Axillary meristems- base of leaves, branches
c. Lateral meristems are parallel to sides of plant parts and increase girth.

6. TYPES OF MERISTEM Primary Growth Secondary Growth Apical Meristems
Vascular cambium
Cork Cambium

7. PRIMARY GROWTH
The apical meristems give rise to three types of embryonic tissue system, called primary meristems.
Protoderm (forms the epidermis)
Procambium (produces the primary vascular tissues)
Ground Meristem (forms the ground tissues)

8. SECONDARY GROWTH
The secondary growth are most dramatic in woody plants, which have two lateral meristems.
Cork Cambium
(produces the cork cells of the outer bark)
Vascular Cambium
(produces secondary vascular tissues)

9. PLANT TISSUES

10. FLOWERING PLANTS HAVE 3 BASIC TISSUE TYPES
Dermal (from the Protoderm)
Cover surface of plant and for Protection
The guard cells, trichomes and root hairs are specialized cells that occurs in the epidermis
Vascular (from the Procambium)
Conducting tissue (Xylem and Phloem)
Ground (from the Ground Meristem)
Consists of the Parenchyma, Collenchyma and Sclerenchyma cells

11. VASCULAR TISSUE Xylem Phloem Mostly to conduct water and nutrients
E.g., roots to shoots
Phloem
Mostly to conduct sugars, amino acids, etc.
E.g., leaves to roots or flowers

12. THE GROUND TISSUES

13. PARENCHYMA CELLS
The most abundant cells of primary tissues, which have large vacuoles and thin walls. They have functional nuclei and are capable of dividing, commonly also store food and water.

14. COLLENCHYMA CELLS
They are relatively flexible, provide support for plant organ, allowing them to bend without breaking. The part of celery that we eat have “strings” that consists mainly of collenhyma and vascular bundles.

15. SCLERENCHYMA CELLS
They are tough and with thick walls their secondary cell walls are often impregnated with LIGNIN, a highly branched polymer that makes cell walls more rigid. They have two types the Fibers and Sclerids. Both of these tough, thick-walled cell types serve to strengthen the tissue in which they occur.

16. Vegetative Organs
Roots
Stems
Leaves

17. ROOTS and ROOT SYSTEMS

18. Root Structure and Function
Penetration of Soil
Gravitropism Downward Growth
Water and Mineral Intake (Absorption)
Storage of Materials
Anchor the plant
Nitrogen Fixation
Conduction (Xylem and Phloem)

19. STRUCTURE OF ROOTS: Longitudinal Section of Roots (Length)
Root cap
Zone of cell division (meristematic region)
Zone of cell elongation
Zone of maturation

20. ROOT CAP
It covers and protects the delicate growing tip of the root from injury and damage
It continuously shed cells that facilitate the growth of the root through the soil.
It gives CO2 to the soil (CO2 + H2O = Carbonic Acid) which dissolves mineral in the soil.

21. MERISTEMATIC REGION
Adds new cells to the root cap and the region of elongation

22. ZONE OF ELONGATION 1 to 3 millimeters above the meristem.
The cell stops to divide, but the cell walls expand and vacuoles increases in size, making the cells longer
Increase in the length of the roots

23. ZONE OF MATURATION Cells are uniform in structure
Cells begin to differentiate and develop into many tissues.
The outermost tissue becomes Epidermis with root hairs

24. Radish seedlings have roots with long root hairs that increase the surface area for water and mineral uptake
©1996 Norton Presentation Maker, W. W. Norton & Company

25. Zone of Maturation - cell differentiation
Zone of Cell Elongation - cell expansion
Zone of Cell Division - new cells by mitosis
Root Cap - penetration, padding

26. STRUCTURE OF ROOTS: Cross Section of Root (Primary Roots)
Root hairs
Cortex
Endodermis (Casparian Strip)
Pericycle

28. STRUCTURE OF ROOTS: Cross Section of Root (Secondary Growth)
Cambium – Growth Tissues
The inner edge of Phloem tissue in the roots is the cambium
The widening in diameter of a root is called secondary growth

31. Types of Roots Fibrous Root System Taproot System
Deep-penetrating Fibrous Root
Fleshy Taproots
Adventitious Roots
Brace or Prop Roots
Climbing Roots
Propagation Roots
……………...

32. THE STEM

33. Function of Stems support leaves to maximize light absorption
part of conduit for transport of water, minerals, and organic solutes
storage

34. TWO TYPES OF STEM
Herbaceous Stems
Woody Stems

35. HERBACEOUS STEM WOODY STEM

37. Fig

38. Fig a

39. Fig b

40. Fig c