Objectives !  Identify the different types of cells found in

plants and their functions.

!  Identify the structures that make up the root system of a plant and their functions.

!  Describe the different types of root systems and their advantages.

!  Identify the structures that make up the stem of a plant and their functions.

Plant Cells !   Plants contain different

types that have a different function based on their shape.

!   Parenchyma Cells are loosely packed cube-shaped cells that store water, conduct photosynthesis, and make up the “fleshy” parts of most plants.

!  Collenchyma Cells are have thick, irregular cell walls that provide support.

!  Sclerencyma Cells are thick, tightly packed cells that make up hardened parts of plants.

Vascular Tissue !  Vascular tissue is

responsible for moving material from one part of the plant to the other.

!   It is found in stems, roots, and leaves.

!  Vascular tissue is made up mostly of sclerenchyma cells.

Roots

!  Roots anchor plants on one place and absorb nutrients/water from the soil to allow them to grow.

!  There are 3 main types of root systems: !  Taproot System !  Fibrous Root System !  Adventitious Root System

Root Systems !   Taproot

Systems consist on one primary or main root with smaller roots that grow from it.

!   EXAMPLES: Carrots & radishes

!   Fibrous Root Systems consist of many small roots that grow in several directions.

!   EXAMPLES: Grasses (most monocots)

!  Adventitious Root Systems are specialized roots that grow from stems or leaves to anchor plant in place. !  EXMAPLES: Orchids & Ivy

Parts of a Root !   The inner parts of a roots include:

!   Vascular Tissue (Xylem & Phloem) !   Pericycle (Tissue that supports vascular bundle) !   Endodermis (Tissue that surrounds vascular tissue) !   Cortex (Tissue protects vascular tissue) !   Epidermis (Outer most tissue) !   Root Hairs (OUTER: Increase surface area and reach)

Stems !   Stems provide support

and materials to the leaves, flowers, fruits/ vegetables, and all other parts of the plant.

!   The outer parts of a stem are: !   Nodes (Where leaves

grow out.) !   Internodes (Space

between nodes) !   Lateral Buds (where a

new shot will form.) !   Terminal Bud (End of

stem.)

Monocot/Dicot Stems !  The inner parts of a stem include:

!  Vascular Bundles (Xylem & Phloem) !  Ground tissue (Monocot)/Pith (Dicot) !  Cortex (Dicot only) !  Epidermis

Secondary Growth of Stems !  Herbaceous stems are soft and usually

represent one season’s growth. !  Woody stems consist of hardened,

woody tissue that moves to the outside of the plant, while new tissue forms on the inside.

!  Woody stems consist of several layers, and can be used to determine the age of a plant.

Woody Stems !   Woody plants grow

differently by season creating rings. Each ring consists of: !   Springwood (Lots of

Xylem because of water.)

!   Summerwood (Little Xylem due to lack of water.)

!   Woody stems consist of: !   Heartwood (Growth) !   Sapwood (Cork) !   Bark (Not all)

Springwood Summerwood Annual Ring