1. Specialized Plant Cells: Transport in Leaves
9 Bio

2. Leaf Structure- Overview
Leaf structure is arranged in layers:
1. Upper epidermis
Waxy cuticle prevents water loss
2. Pallisade layer
Chloroplasts – photosynthesis (glucose production)
3. Spongy pallisade layer
Storage of H2O, CO2 and O2
4. Lower epidermis
Stomata and guard cells regulate the passage of water vapor( transpiration), intake of CO2, output of O2

3. Palisade Mesophyll Layer
Contains chloroplasts:
Outer membrane
Granum- stack of thylakoids
Thylakoids- contain chlorophyll, catch photons of light photosynthesis glucose
Stroma- fluid filled space

4. Spongy Mesophyll Layer
Open space to store gases ( CO2 and O2) and H2O molecules for exchange in atmosphere
CO2 needed for photosynthesis
O2- by-product of photosynthesis
H2O- transpiration

5. Lower Epidermis Has guard cells surrounding stomata Stomate (singular)
Opening and closing of stomata regulated by plant hormone abscisic acid
Abscisic acid present: K+ leaves, H2O leaves, stomata close
Abscisic acid absent: K+ stays, H2O stays, stomata open

6. Regulation of Transport
Lower Epidermis:
Takes in CO2 for photosynthesis
Releases O2 from photosynthesis
Releases H2O (Transpiration)
Why would stomata remain closed in arid conditions?
When might plants lose the most H2O?
When might plants produce a high level of O2?
When might plants need a greater amount of CO2?