seed dispersal and germination interest grabber from fruits to nuts walk into any supermarket and...

Seed Dispersal and Germination

Interest Grabber

•From Fruits to Nuts

•Walk into any supermarket and you will likely see a variety of fruits. Would it surprise you to learn that many of the foods that you think of as vegetables, grains, and nuts are actually fruits?

•1. Name three fruits that you have eaten.

•2. Describe any seeds you found in the fruits.

•3. What function do you think the fruit and seeds serve for a plant?

Section 24-2


Section Outline

• 24–2 Seed Development and GerminationA. Seed and Fruit Development

B. Seed Dispersal

1. Dispersal by Animals

2. Dispersal by Wind and Water

C. Seed Dormancy

D. Seed Germination

Section 24-2


that

Concept Map

in

have

Section 24-2

that

have

SeedGermination

Remains withthe seed

Emergeabove ground

Remainbelow ground

Monocots Dicots

1 Cotyledon 2 Cotyledons


KEY CONCEPT Seeds disperse and begin to grow when conditions are favorable.


Animals, wind, and water can spread seeds.

• Seeds dispersed by animals can have nutritious fruits or fruits that cling.


• Seeds dispersed by wind can have wing- or parachute-like fruits.

Cypselae

Double samaras


• Seeds dispersed by water can have fruits that float.


Seeds begin to grow when environmental conditions are favorable.• Seed dormancy is a state in which the embryo has stopped

growing. – Dormancy may end

when conditions are favorable.

– While dormant, embryo can withstand extreme conditions.


Seed Diagram


• Germination begins the growth of an embryo into a seedling.

– water causes seed to swell and crack coat– embryonic root, radicle, is first to emerge– water activates enzymes that help send sugars to

embryo


• Germination begins the growth of an embryo into a seedling. – water causes seed to swell and crack coat– embryonic root, radicle, is first to emerge – water activates enzymes that help send sugars to

embryo– embryonic shoot, plumule, emerges next


• Germination begins the growth of an embryo into a seedling. – water causes seed to swell and crack coat– embryonic root, radicle, is first to emerge – water activates enzymes that help send sugars to

embryo– embryonic shoot, plumule, emerges next

– leaves emerge last


• Once photosynthesis begins, the plant is called a seedling.

seed dispersal and germination interest grabber from fruits to nuts walk into any supermarket and...

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