Leaves

S7-3-1 Look! Vascular tissue!

1 main function of a leaf

Make food It uses the process photosynthesis to

make food for the plant (more on this later!)

2 types of leaves

Simple—blade in one piece

Ex. maple, oak, apple trees Compound—blade

is divided into many leaf-like parts

Ex. marigold, sensitive plant

Photosynthesis

Food is synthesized (made) using sun’s energy

Sun’s energy is captured by chlorophyll (green pigment in the leaf)

Chemical reactions take place—sugar (AKA glucose AKA C6H12O6)

6H2O + 6CO2 ----------> C6H12O6+ 6O2

C6H12O6

**AKA = Also Known As

Add sunlight

Parts of a leaf

Mesophyll: inner part of leaf

Veins: Phloem & xylem

Cuticle: waxy covering, prevents excess water loss

Epidermis: outer covering

Palisade mesophyll: most chloroplasts located here

Spongy mesophyll: gases (CO2 & O2) are exchanged here

Stoma: opening for CO2 to come in & O2 to go outGuard cells: Surround stoma, regulate its opening & closing

Enlarged view:

**I apologize for this blurriness of this picture!It is as if the leaf is cut in half and you are looking at a side view!

Transpiration Water is evaporated

through the leaves by the sun

Each time a water droplet is “picked up,” it pulls the next droplet through

This is how the water gets from the roots to the leaves

Red arrows show the path of the water

Specialized leaves #1

Tendrils—Thin leaves that reach out and “lasso” objects to help plant extend itself

Ex. peas, pumpkins

Spines—Thin, pointy leaves; help to reduce water loss

Ex. Cacti

Specialized leaves #2

Reproduction— “babies” drop from the grown leaf

Ex. Spider plant Kalanchoe

• “Fake petals”—Some leaves are brightly colored and look like petals (to attract pollinators)• Ex. Poinsettias

Specialized leaves #3 Carnivorous plants—some leaves catch

insects to eat sundew

insects get stuck on sticky drops on leaves

Pitcher plantInsects land on leaf and slide down

into digestive juice Venus flytrapSnap shut when insect lands on leaf

We EAT the leaves of many plants!

Specialized leaves #4 FOOD!

Cabbage

Herbs, such as parsley

and basil

Spinach

Lettuce

Bulbs: Onion and garlic

Cloves

Questions: Please answer of separate piece of paper

1. List the one main function of a leaf.2. What category of leaf is shown here:3. What 2 substances react with each other during

photosynthesis?4. What 2 substances are produced through

photosynthesis?5. Can a plant make food in the dark? Explain.6. What part of the leaf captures the sun’s energy? In

which section of the leaf are these organelles located?7. What is the job of the cuticle?8. In which direction does transpiration move water?9. Name 3 specialized functions of leaves (besides food).10. List your 3 favorite leaf foods.