1. Seed Plant Organs, Tissues, and Systems
Lesson Overview
Seed Plant Organs, Tissues, and Systems

2. Seed Plant Structure Organs: The principal organs of seed plants are:
roots
stems
leaves

3. 1. Roots Functions of the Root: 1. anchor plants
2. absorb water and dissolved nutrients.
3. stores food
4. hold plants upright against forces such as wind and rain

4. Stems Functions of the Stem:
provide a support system for the plant body
2. transport system that carries nutrients from the roots to the leaves
3. defensive system that protects the plant against predators and disease

5. Functions of the Leaves:
1. the plant’s main photosynthetic organs.
2. have adjustable pores that help conserve water while letting oxygen and carbon dioxide enter and exit the leaf.

6. Plants have three main tissue systems: dermal vascular ground
Plant Tissue Systems
Tissues:
Plants have three main tissue systems:
dermal
vascular
ground

7. Plant Tissue Systems
Dermal tissue: is the protective outer covering of a plant.
Vascular tissue: supports the plant body and transports water and nutrients throughout the plant.
Ground tissue: produces and stores sugars, and contributes to physical support of the plant.

8. 1. Dermal Tissue
Dermal tissue is the protective outer covering of a plant.
In young plants dermal tissue consists of a single layer of cells, called the epidermis.
The outer surfaces of epidermal cells are often covered with a thick waxy layer called the cuticle, which protects against water loss.
In older plants, dermal tissue may be many cell layers deep and may be covered with bark.

9. 2. Vascular Tissue
Vascular tissue supports the plant body and transports water and nutrients throughout the plant.
Vascular tissue included:
Xylem - a water-conducting tissue
Phloem - a tissue that carries dissolved food

10. 3. Ground Tissue
Ground tissue produces and stores sugars, and contributes to physical support of the plant.
Three types of ground tissue:
parenchyma (thin cell walls)
collenchyma (thicker cell walls)
sclerenchyma (thickest cell walls)

11. Plant Growth and Meristems
Even the oldest trees produce new leaves and new reproductive organs every year, almost as if they remained “forever young.”
Meristems: are regions of unspecialized cells in which mitosis produces new cells that are ready for differentiation.
Meristems are found in places where plants grow rapidly, such as the tips of stems and roots.

12. Apical Meristems
Apical meristems: Unspecialized cells produced in apical meristems divide rapidly as stems and roots increase in length.
As the cells differentiate, they produce each of the tissue systems of the plant, including dermal, vascular, and ground tissue.