Assignment # Transpiration (Transport in Plants) Biology Mrs. McCarthy Monday, April 24, 2017

Plants are made of tissues that form organs Plant organs are: 1. Roots I. Plant tissues Plants are made of tissues that form organs Plant organs are: 1. Roots 2. Stems 3. Leaves 4. Reproductive structures – flowers, fruits, seeds

I. Plant tissues

Plants have vascular tissues that transport materials 1. Xylem carries water and minerals a. Xylem only carries one way – from roots to leaves b. Roots absorb the water by osmosis needed by the plant

2. Phloem carries food and other dissolved materials a. phloem can carry food to and from the leaves – both ways b. food is made in the leaves during photosynthesis

c. Plant carbohydrates are stored as: 1. Starch (can be digested) 2. Fiber or cellulose (cannot be digested) d. Extra food is stored in the roots

e. In the spring, when plants. need energy to make e.In the spring, when plants need energy to make leaves, the sap moves up the phloem f. Sap is made of dissolved raw materials (carbohydrates)

I I. Transpiration – evaporation of water from plant surfaces All plants need water to survive, but much of the water is lost to the atmosphere by evaporation Cuticle is the thin, waxy outer layer of a leaf that helps to prevent water loss and protects the plant from infections

Transpiration takes place through stomates Stomates are pores in the epidermis of a leaf 1. Pores – tiny holes or openings 2. Epidermis – outer covering of the leaf

3. Stomata (stomates) are. used for the exchange of 3. Stomata (stomates) are used for the exchange of oxygen and carbon dioxide during photosynthesis

The rate of transpiration is controlled by the size of the opening of each stomate 1. Guard cells control the opening and closing of each stomate

2. The stomata open and. close as the guard cells 2. The stomata open and close as the guard cells gain or lose water by osmosis a. When guard cells become swollen with water (called turgid), the uneven thickness of their walls cause them to bend outward. This makes the stomate OPEN.

b. When the guard cells lose. water, they shrink and the b. When the guard cells lose water, they shrink and the cells come close together. The stomate CLOSES.

The stomata of most plants are open during the day for photosynthesis to occur, and they close at night. a. However, the stomata will close when: 1. The plant does not have enough water 2. The temperatures is low 3. There is little or no light

Journal Entry # April 24, 2017 How would a plant change if placed in colored water for 24 hours? Explain using these words: Xylem, stomates, transpiration

Label the Leaf Cross Section Diagram