1. Plant Structure and Function

2. Specialized Tissues in Plants Plant Organs: Roots, Stems, and Leaves
Anchor the plant and absorb nutrients and water
Mutualistic relationship with mycorrhizae and rhizobacteria
Transport Nutrients to the plant
Store Food

3. Specialized Tissues in Plants
Stems
Support the plant
Transport water and nutrients
Protect against predators and disease

4. Specialized Tissues in Plants
Leaves
Conduct photosynthesis
Increased SA:V with leaf size
Protect against water loss
Waxy cuticle
Stomata and Guard Cells

5. Specialized Tissues in Plants Plant Tissues: Dermal, Vascular, and Ground Tissue

6. Specialized Tissues in Plants
Dermal Tissue
Covers the plant
Epidermis (epi = upon) –
single layer of cells on the outside of the plant
Cuticle – layer of wax that covers the epidermis and prevents water loss (polarity?)
Trichomes – tiny hairlike projections for protection
Bark – covers the epidermis in woody plants
Root hair cells are found on the epidermis of roots to help absorb water (SA:V)

7. Specialized Tissues in Plants
Vascular Tissue
Vessels that transport water and nutrients
Plant “bloodstream”
Xylem – carries water
Phloem – carries nutrients

8. Vascular Tissue - Xylem
Tracheids – hollow plant cells of the xylem with thick cell walls strengthened by lignin
Lignin resists water and is a major constituent in wood
Openings in the cell walls of tracheids allow water to pass from cell to cell and therefore be transported throughout the plant
Vessel Elements - hollow plants cells of xylem stacked end to end.
Water passes from cell to cell through slit-like openings on the ends of each cell

9. Vascular Tissue – Phloem
Sieve Tube Elements – cells of the phloem that are arranged end to end and allow nutrients to flow throughout the plant in a watery stream
Companion Cells – cells of the phloem that the sieve tube cells and aid in the movement of nutrients

10. Specialized Tissues in Plants
Ground Tissue
Produces and Stores food (sugars)
Composes most of the edible portions of plants
Contributes to the physical support of the plant
Ground tissue is composed of three main types of cells
Parenchyma
Collenchyma
Sclerenchyma

11. Ground Tissue Parenchyma
Makes up the highest percentage of ground tissue
Thin cell walls
Large central vacuole
Limited cytoplasm
Contain many chloroplasts in leaves and are the main sight of photosynthesis

12. Ground Tissue Collenchyma Sclerenchyma
Chains of strong, flexible cell walls
Provide support for plant organs
Sclerenchyma
Extremely thick and rigid cells walls
Found on seed coats (strong!)
Have been used to make rope from hemp

13. Plant Growth and Meristems
Meristems – regions of specialized plant cells in which mitosis produces new cells ready for differentiation
The undifferentiated cells produced are much like the stem cells of animals
Located in parts of plants that undergo rapid growth
Allow even the oldest trees to produce new leaves and new reproductive organs each year

14. Apical Meristem – located at the end (apex) of a root or stem.
Leads to increase in root or stem length
Once produced, the new cells differentiate into new dermal, vascular, and ground tissue

15. Floral Meristems Produce the tissues of flowers
Includes the plant’s reproductive organs as well as the colorful petals that surround them