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