Fruit Development &

Dispersing Fruits and Seeds

How to get around when you’re rooted

in the ground

Review of prior

learning

What did you already learn about fruits?

Frui

t Dev

elop

men

t

When the ovary is fertilized it begins to

swell. This is called a FRUIT SET.

Frui

t Dev

elop

men

t: Ho

rmon

es

Fruit Development is driven by

hormonesOur old friend Auxin is involved

We also see a new player, the

hormone giberellinIf you apply auxin or gibrellin to

the ovaries of unfertilized flowers you develop

parthenocarpic (seedless) fruits

Frui

ts ri

pen

when

see

ds

are

read

y fo

r disp

ersa

l

What does it look like when fruit ripens?• Changing from green to another

color• Sweetening• Softening

Seed

Disp

ersa

l

• Plants can’t move around like

animals• They have to get creative; you

can’t just let the offspring grow on

top of the parents• Seed dispersal is how they move

their seeds.

Win

d Di

sper

sal

• Some seeds and fruits can be

carried on the wind.• Maple seeds act like little helicopters• Dandelion seeds act like little

parachutes• These seeds and fruits must be

light weight

Anim

al D

isper

sal

• Some seeds and fruits hitch a ride

with an animal• Animals eat seeds and excrete

seeds elsewhere• Burrs and prickles hold onto animal fur

Mec

hani

cal D

isper

sal

• Some plants want to do it on their

own• Mechanical Dispersal means the

seeds fling themselves away from

the plant• Examples are “touch me nots”

and witch hazel

Wat

er D

isper

sal

• Some plants set sail• Waxy coatings make it possible

for some fruits to float on water• These plants can discover and

inhabit new islands