1. an integrated group of cells with a common structure and function
Tissues
an integrated group of cells with a common structure and function

2. Plant Tissues Four tissue systems in plants:
Meristematic tissue: rapid cell division, lengthening of shoots and roots
Dermal tissue: provides covering for the plant body.
Ground tissue: variety of functions including support, photosynthesis, and storage
Vascular tissue: “plumbing system” throughout plants; conducts water, food (CH2O), and dissolved minerals; also strengthens and supports the plant.

3. Plants Exhibit Localized Growth at Meristems

4. Meristematic Tissue
specific areas of plant growth composed of cells that do not differentiate
cells retain the ability to divide, which other plant cells lose
allow plants to grow their entire lives
Types:
Apical – primary growth at root and shoot tips
Lateral – secondary growth in trees and shrubs
Intercalary – secondary growth in monocot stems

5. Apical meristem In shoot tips and root tips
Region of cell differentiation/maturation
Region of cell elongation
In shoot tips and root tips
Allium cepa root tip shown here
Parenchyma cells
Region of cell division
Apical meristem
Root cap

6. Apical Meristems
Stem buds have a dome-like apical meristem in addition to leaf primordia and bud primordia, which protect the apical meristem.

7. Dermal Tissue System

8. Dermal Tissues
Single layer of cells called the epidermis in herbaceous plants
Guard cells
Trichomes
Root hairs
Functions
Absorption
Secretion of cuticle
Protection
Control of gas exchange
Epidermis
Cuticle

9. The Ground Tissue System

10. Parenchyma cells
Spherical-shaped cells; most common type of tissue (most of apples & potatoes); found throughout plant
Have thin primary walls
Living, metabolizing tissue
Functions:
Photosynthesis & respiration
Storage (starch, oil droplets, water, and salts)
Wound healing & regeneration

11. Collenchyma
Beneath the epidermis in young stems and in large veins of leaves (“strings” in celery)
Elongated cells that have unevenly thickened cell walls (especially in the corners)
Flexible support system (like our skeletal system)
Found uniformly throughout the plant
Alive at maturity

12. Sclerenchyma Specialized for structural support; occurs in many areas
Two types:
Fibers – support in wood, bark, leaves, stems
Sclereids – protection in fruits, seeds, other plant organs
Primary and secondary cell walls.
Dead at functional maturity
The root of the word sclerenchyma is the Greek word root (sclero) meaning “hard”

13. The Vascular Tissue System

14. Complex Vascular Tissues
Xylem
Conducts water and dissolved minerals from the roots
Phloem
Conducts dissolved food materials, carbohydrates, in solution
Continuous throughout plant
Support plant body

16. All 4 types of tissues are present in the root tip

17. Young monocot stem
Young dicot stem