1. Plant Characteristics and Special Functions
Plants
Plant Characteristics and Special Functions

2. Overview of Plants
all shapes and sizes
all types of environments

3. Common Characteristics of Plants
About 260,000 species of plants live on Earth today.
All plants:
Are multicellular
Have a nucleus surrounded by a cell wall.
Are producers – capture light from the Sun.
Have life cycles divided into two stages (generations).

4. Special Functions Below ground: roots
Absorb water and nutrients from soil.
Transport materials to leaves through the stem.
Above ground: stems and leaves = shoot system
Leaves use materials + CO2 to make sugars and carbohydrates through photosynthesis.

5. Transporting Materials
Materials move through a vascular system.
Stems transport the materials from one part of the plant to another.
The vascular tissues are bundled together from the root to the leaves; look like tubes.

6. Transporting Materials - Tissue
Xylem: carries water and dissolved nutrients up from roots.
Phloem: transports energy-rich materials, such as sugar, down from leaves.
Both are long, hollow tubes that contain fibers to support the body of the plant.
Xylem is a little larger.

7. Transporting Materials - Tissue

8. Making Sugars - Photosynthesis
Plants make sure through photosynthesis.
What is the formula?
Co2 + H2O + sunlight  oxygen + glucose (C6H12O6)
Where does it take place?
In the chloroplasts, which contain chlorophyll

9. Inside of the Leaf Upper layer is filled with chloroplasts.
Vascular tissue is located toward the center.
Stomata, or tiny openings, are located on the bottom of the leaf – gas exchange occurs here (CO2 comes in, O2 goes out).

10. Controlling Gas Exchange
Stomata can open and close to let CO2 and oxygen in and out.
Water is able to evaporate from open stomata  transpiration.
Sunlight and wind cause transpiration.

11. Water Loss
Plants have a waxy cuticle, or protective layer, to prevent too much water from evaporating.
Stomata can open and close to prevent this, also.

12. Adapting to Environment - Cactus
Special adaptation – no leaves – uses spines instead.
Photosynthesis occurs in the stem, where the cactus is able to hold more nutrients without the threat of transpiration.

13. Plant Growth Plants grow as long as they live.
They get bigger when cells at the tips of their roots and stems divide and multiply more quickly than other cells.
Only stems grow leaves – leaves grow from buds.

14. The Stem – Three Functions
Holds the vascular system
Provide support and plant structure
Store sugars produced by photosynthesis

15. Soft Stems Wildflowers, garden flowers, and vegetables
Survive by using the carbs stored in its roots to grow new, soft, green stems and leaves in warmer weather.

16. Woody Stems Trees and shrubs
Tough, thick stems that do not die each year.
Keep growing longer/thicker
Tough xylem layer  wood