4.6 Seed Dispersal and Germination

Seed structure : What is the epicotyl

The epicotyl is the embryonic shoot

Seed structure : What is the Radicle

The Radicle is the embryonic root

Seed structure : What is the Micropyle

Small pore for water passage

Seed structure : What is the cotyledon

embryonic leaf containing food reserves

Seed structure : What is the Testa

Seed coat to protect embryo

Seed structure : Identify components on diagram (draw it)

What are the three dispersal mechanisms for seeds

1) Wind —→ dandelion, maple trees

2) Animals —→ squirrels planting acorns, tomatoes

3) Water —→ water lilies

Seed anatomy will depend on dispersal methods

Steps for seed germination: Phase 1

Phase 1 : Activation

• Seed absorbs water via micropyle (becomes metabolically active)

• Water promotes production of phytohormone, gibberellin

• Gibberellin promotes synthesis of digestive enzymes

• Enzymes convert food reserves (starch) in the cotyledon into glucose for energy

Steps for seed germination: Phase 2

Phase 2 : Growth

• Testa ruptures and radicle roots into the ground

• Cotyledon emerge allowing for photosynthesis

• Plant continues to develop, forming adult tissues

What is biosynthesis

Biosynthesis is the process of creating essential biological molecules line proteins, DNA, and complex carbohydrates