1. To Do: Thursday 1. Check your concept map with one of the keys around the room 2. Go to one of the microscopes and fill in your half sheet warm-up 3. Plant Book – Transpiration notes 4. Cross Section of a Leaf Cutout

3. Guard cells: cells that open and close the stoma Stomata: openings in underside of leaf’s surface; when open: GAS EXCHANGE: Allows CO 2 in & O 2 out of leaf TRANSPIRATION: Allows excess H 2 O out of leaf

4. GUARD CELL WITH STOMATA

5. Guard Cells Stomata (stoma)Cuticle Epidermis Vascular bundle (vein) Chloroplasts

6. A average size maple tree can transpire 200 liters of water per hour during the summer. Transpiration is the #1 driving force for pulling water up stems from roots. 1.Transpiration: loss of excess water from plant leaves 2. Significance: a.Transpiration causes enough pressure to help pull water (& required nutrients) up stem from roots. b.As part of the water cycle, trees transpire water back into the atmosphere. c.Transpiration provides much of the daily rain in rainforest.

7. The bulk of most leaves consist of a specialized ground tissue full of chloroplasts known as mesophyll. The mesophyll contains two layers: 1. Palisade Layer – Closely packed tall columnar cells; located under the upper epidermis and absorbs light that enters the leaf. 2. Spongy Layer – Loose tissue made of spherical cells that contains many air spaces between its cells; the air spaces connect with the exterior through the stomata (pore-like openings that allow gases to enter and leave the leaf ). The stomata and guard cells are also located on the leaf (already discussed these structures previously).

8. A.Cuticle- outer waxy covering that protects from water loss B.Epidermis- outer tissue layer C.Pallisade layer- contains the majority of chloroplasts D.Mesophyll- middle tissue layer includes spongy & palisade E.Spongy layer- contains chloroplasts & exchange of gasses F.Guard cells- control the opening and closing of the stoma G.Stomata- pores that allow gasses to enter and leave the leaf H.Vein- the vascular bundle, which contains xylem and phloem. guard cell stomata vein

9. Guard cells Vein stomata