Plant Tissues

What are tissues?

Collection of specialized cells carrying out 1 function

4 ex of plant tissues

1. Meristems

2. Epidermis

3. Vascular tissues

4. Food storage tissues

3 categories of plant tissues

1. Dermal

2. Ground

3. Vascular

What are meristems?

• Parenchyma

• Cells that promote plant growth

Mitosis

Creates additional cells that typically have the same characteristics of the original cell

Three primary meristems develop from the….

apical meristem

What are the 3 primary meristems that develop from the apical meristem?

1. Protoderm (epidermal layers)

2. Ground meristem (pith and cortex)

3. Procambium (primary xylem and phloem)

Lateral meristems are responsible for growth in girth of what 2 things?

1. Stems

2. Roots

Lateral meristems produce secondary tissues of…

1. Vascular cambium (secondary xylem and phloem)

2. Cork cambium (bark)

What are the 3 ground tissue types?

1. Parenchyma

2. Collenchyma

3. Sclerenchyma

3 characteristics of parenchyma

1. Spherical

2. Thin-walled

3. Living, metabolizing tissue

Location of parenchyma

Throughout the plant

3 functions of parenchyma

1. Photosynthesis and respiration

2. Storage

3. Regeneration

Parenchyma

2 characteristics of collenchyma (what are the walls like and are they dead or alive at maturity)?

1. Elongated cells with unevenly thickened cell walls

2. Alive @ maturity

Location of collenchyma

Beneath the epidermis in young stems and leaf veins

Function of collenchyma

Flexible support system

Collenchyma

2 characteristics of sclerenchyma

• With primary + secondary walls

• Dead @ functional maturity

2 locations of sclerenchyma

• Fibers in wood, bark, leaves, stems

• Sclereids in fruits and seeds

Function of sclerenchyma

Structural support

Sclerenchyma

Where are ground tissues found?

1. Leaves

2. Stems

3. Fruits

4. Flowers

5. Roots

6. All plant parts

Vegetable example of parenchyma tissue

Potato

Vegetable example of collenchyma tissue

Celery

Fruit example of sclerenchyma tissue

Pear

Epidermis

• Single layer of exterior (parenchyma) cells

• Protects various plant organs (leaves, stems, flowers, roots)

Root cap

• Protects root meristem (parenchyma)

• Replenished daily by root meristem

Leaves

• Outer layer (parenchyma cells)

• Protects inner contents of leaf

Guard cells

• Differentially thickened cells that become turgid during the day

• Expand to form pores called stomata

2 types of vascular tissues

1. Xylem

2. Phloem

Where are guard cells located?

Primarily on the underside of leaves

2 functions of guard cells

1. Gas exchange

2. Regulate water loss

Xylem function

Conduct water + dissolved minerals

Cells in xylem

Sclerenchyma

Phloem function

Transports sugars, amino acids, hormones

Cells in phloem

Parenchyma

How are vascular tissues arranged?

Bundles

Epidermis function in roots

Protection

Epidermis cells in roots

Parenchyma

Cortex function in roots

Food storage

Cortex cells in roots

Parenchyma

Endodermis function in roots

• Controls water movement to xylem

• Covered with a wax coating (casperian strip)

Endodermis cells in roots

Parenchyma

Pericycle function in roots

Cell division

What cells make up the pericylce in roots?

Parenchyma cells

What type of cells make up the cortex in a dicot seed?

Collenchyma

Cambium function in dicot stems

Produces new vascular cells and tissues

Cambium cells in dicot stems

Parenchyma

Pith function in dicot stems

Structure

Arrangement of tissues: monocot stems

• Scattered vascular bundles

• No secondary growth

• Increases in diameter

Secondary growth

Bark

What is secondary growth?

Thickening of stems and roots (in many cases, the production of wood)

Cork cambium is located just inside the…

epidermis

Most tissues are composed of what type of cells?

Mature

Most tissues are composed of mature cells except…

Meristem tissues

Combinations of tissues make up organs such as…

Leaves

Purpose of cuticle (leaf tissue)

• Waxy coating over the episdermis

• Protection from water loss

Epidermis purpose + cell type(leaf tissue)

• Protection

• Parenchyma

The palisade parenchyma (or palisade layer) is a group of ________ cells in the leaf that are the main site of __________

1. parenchyma

2. photosynthesis

Spongy (leaf tissue)

• Secondary site for photosynthesis

• Loosely packed

• Parenchyma

A vascular bundle is a group of what 2 tissues?

• Xylem

• Pholem

What are the 3 primary meristems develop from the APICAL MERISTEM:

1.Protoderm (epidermal layers)

2. Ground meristem (pith and cortex)

3. Procambium (primary xylem and phloem)

LATERIAL MERISTEMS produce secondary tissues of what 2 things?

1. Vascular cambium (secondary xylem and phloem)

2.  Cork cambium (cork = bark)