1. Plant Tissues
Plant structures are composed of 4 main tissues. They are:
Epidermis – outer layer of cells which protect the plant from water loss and from fungi and bacteria
Vascular Tissues – transport water, sugars and other materials through the plant
Ground Tissues – tissues that the vascular tissue is embedded in…. usually storage cells
Meristematic – cells that divide

2. Plant Tissues Meristematic- growth Epidermal- protection
Parenchyma- storage
Sclerenchyma- strengthen and support
Vascular- transportation
xylem = water + nutrients
phloem = plant products in solution

3. Plant Tissues

4. In Most Plants
Glucose is produced in the leaves through photosynthesis.
The glucose is converted to sucrose (by dehydration synthesis) for transportation.
The sucrose is converted to starch and stored.

5. Roots Roots have many functions.
1. anchor the plant
2. bind soil… stops erosion
3. absorb water and minerals
4. store food (usually as starch)

6. Root Types

7. Taproots look large and fleshy,
are mostly found in plants with two seed-leaves (dicots),
grow deep into the ground to search for food,
are able to store food, which is particularly necessary for perennial plants during periods of dormancy.

8. Fibrous roots lie close to the surface of the soil,
are mostly found in plants with one seed-leaf (monocots)
collect precipitation before it sinks deep into the ground,
can often be found growing side by side with taproots- the two types of roots combine efforts to maximize efficiency.

9. Adventitious roots are common in both dicots and monocots
develop to help the plant climb: for example, ivy
help develop modified underground stems, such as bulbs

10. Aerial Roots modified to absorb water from the air
Aerial roots of an Orchid Orchids in bloom

11. Root Hairs are actually epidermal cells adapted to absorb water
* Water enters the cells by Osmosis
* Minerals enter by Active Transport

12. Regions of the root tip
Region of Maturation - Most cells differentiate into various distinctive cell types.
Root hairs form.
Region of Elongation - Cells become several times their original length.
Vacuoles merge
Region of Cell Division - Composed of apical meristem in the center of the root tip.
Most cell division occurs at the edge of the inverted cup-shaped zone.
Root Cap - Thimble-shaped mass of parenchyma cells covering each root tip.
Protects tissue from damage.
Function in gravity perception.

13. The Root Tip

14. The Function of Root Tissues
Epidermis – outer layer of cells, provide protection from drying out, water loss and infection.
Cortex – area made up of parenchyma cells. Parenchyma cells are usually storage cells
Endodermis – regulates materials entering the center of the root.
Pericycle –the outermost layer of cells of the stele
Xylem – transports water
Phloem – transports sugar
Stele – Also known as the “Vascular Cylinder”…… made up of the xylem and phloem
Pith – tissue located in the center of the stem
Apical Meristem - (Meristematic Tissue) – tissue that in a constant state of growth… apical means “located at the tip”
Meristem accounts for the increase in length of the roots and stems.

15. Dicot Root X-section

16. Monocot root X-section

17. Dicot root X-section Most Dicot roots have an “X” of xylem cells in the center of the root.

18. The Casparian Strip regulates the movement of water into the root

19. Stele