When I first started studying botany, I quickly
realized that everything I thought I knew
about fruits and vegetables was a lie.
fruits
not a fruit
Not a berry
Not a berry
Yes a berry
Also this
Hair
Not a nut
Still not a nut
Literally nothing is a nut...except for these!
*whisper screams*
Whew OK let’s all take a deep breath -
it’s gonnabe OK
*intro music*
*intro music*
All right team I know that was a lot - don’t
worry, we’re gonna break it down one earth-shattering
botanical truth at a time.
So here’s the deal with fruits and vegetables:
culinarily-speaking, we think of fruits as
sweet, and vegetables as savory.
Botanically, however, it’s a completely
different story. And that's because
fruits have a very strict botanical definition,
whereas vegetables...well, the word ‘vegetable’
doesn’t mean anything in botany.
I'm sorry vegetables, we still love you!
Vegetables can come from
any part of the plant - eggplant, zucchini,
and tomatoes are all fruits, but carrots and
radishes are roots, potatoes are underground
stems, lettuce and onions are leaves, and
broccoli...you know, we’re gonna have
to do a whole other episode about broccoli
because that sh**’s crazy.
Fruits, on the other hand, refer to one specific
part of the plant in botany: they're mature plant ovaries!
I just love a good plant ovary
Now to really understand the true meaning of fruit, we're gonna have to do a deep dive into plant reproduction
specifically, flowering plant reproduction,
because only flowering plants make fruits.
So you won’t see a fruit on a moss, fern,
or pine tree.
Flowers contain the plant’s reproductive
organs.
Stamens are the male organs - their anthers
make pollen, which contain sperm cells.
The carpels are the female organs - they consist
of a stigma, style, and ovary.
In the ovary, you’ll find ovules that each
contain an egg.
The sepals and petals serve to attract pollinators
that move pollen from the anthers of one flower
to the stigma of another flower.
Sperm from the pollen travel down the style
and into the ovary, where they fertilize the
eggs in the ovules.
Each ovule will mature into a seed.
The fertilized egg develops into an embryo,
aka a baby plant, inside the seed!
It remains dormant until the seed can move
away from the parent plant and find an ideal
spot to germinate and grow.
And how does it move away??
The fruit!
The ovules are becoming seeds inside the ovary,
which itself is maturing into a fruit!
So, the purpose of fruits is to disperse
seeds! plants want to spread their offspring
as far and wide as possible to ensure their
success.
Fruits come in every shape and size imaginable
to take advantage of every dispersal method
imaginable - some fruits are juicy and delicious so they get eaten by animals that will
poop out the seeds later; some fruits have
spikes to help them hitch a ride on a passing
critter; some are aerodynamic and can soar
through the air; and others can float on the seas
Botanists could fill a dictionary with terminology
just for describing these different types
of fruits, but we’ll go through the important
ones that will help make sense of everything
I told you at the beginning of the episode.
Are you ready? OK.
Fruit tissue is called pericarp, and consists
of three layers: exocarp (the outer layer),
mesocarp (the middle layer), and endocarp
(the inner layer).
Fruit types are defined based on the characteristics
of these pericarp layers, as well as the number
of ovaries a flower has.
A berry is a fruit with a completely fleshy
pericarp that came from a flower with a single ovary
A tomato is a great example - and if I cut it open, we can see that all the layers
are soft and fleshy - the skin is the exocarp, we have the mesocarp here, and a pulpy endocarp
Avocados are berries - the leathery exocarp
still counts as soft.
And, blueberries are actually berries! So, not everything is a lie
You can see there are no rules about seed
number - a single ovary can contain multiple
seeds, or just one
Citrus fruits are a special type of berry called a
‘hesperidium.’
The entire rind of the orange is actually all three layers of the pericarp
So, what are we eating when we eat an orange?
Well, it turns out that citrus fruits are lined with tons of special hairs that are filled with juice - so when
you eat oranges you're biting into a giant ball
of plant ovary hair.
Mmm
This is probably closer than you ever wanted to look at oranges especially
now that you know their deep secrets
Peaches, plums, and nectarines may look like berries, but they are actually a different
type of fruit called a “drupe”.
And if we cut it open, you'll see why
Only the exocarp and mesocarp of drupes are fleshy.
The endocarp is hard and stony -
*knock knock* anybody there?
This is the pit - so I used to think this was just the seed,
but it’s actually the innermost layer of
the fruit, and the seed is inside of that.
Once you crack it open, *then* you’ll find
the seed inside.
*grunts*
*surprised laughter*
hmmm OK
haha nope
*loud smashing noises*
ah....oops
You can see that the endocarp has a little chamber inside, and that's where the seed was!
Nuts 
are fruits with completely dry pericarps that
are indehiscent. That means that they don’t open up
to release their seeds.
So peanuts don’t count because while they’re completely
dry fruits too, they are dehiscent,
meaning that they open up to reveal the seeds we eat.
And walnuts and almonds are seeds that come
from drupes!
True nuts are things like acorns and chestnuts.
OK, but what happens when a flower has more
than one ovary?
You can see this blackberry flower has tons
of carpels - each one has an ovary that will
make a fruit, and as they grow
and ripen they all get kind of stuck together
and you wind up with a blackberry.
This is called an ‘aggregate fruit.’
Each individual fruit on the blackberry is actually
a little drupe, so blackberries are aggregates
of drupelets, which is the cutest word in botany, ever.
You can also have the opposite situation,
where single ovaries from multiple
flowers all combine into one fruit - this is fittingly
called a multiple fruit
Anyone wanna guess what a cool example is??
Pineapples!
So this used to be a stem with lots and 
lots and lots of flowers on it
All the different segments are single ovaries from all these different flowers
that have all fused together into this beautiful pineapple isn't that so cool??
Strawberries are a whole other story - the
delicious part of the strawberry isn't a fruit at all!
It's the base of the flower, called the receptacle, that 
swells and grows and becomes red and sweet.
The actual fruits of the strawberry are all the
things you probably think are seeds on the
surface of the receptacle! Crazy! What??
And now, a confession: I too have lied to
you about fruit.
Remember this?
just love a good plant ovary
Well, similarly to strawberries, the delicious
part of the apple is receptacle tissue
Only the *core* of the apple is fruit, so
I wasnt actually biting into the ovary here.
The crunch was just too good to pass up!
But, I am very sorry to have misled you.
Well I hope this episode has given you some newfound respect for fruits
and sympathy for vegetables
There are a bazillion types of fruits out there and we only got to cover a few today
so I'll put some links in the description for a more comprehensive list
Don't forget to subscribe, and for more...fruitful Science IRL episodes,
You can meet scientists who are finding a cure for citrus greening disease,
or learn how to extract DNA from strawberries!
And I'm coming for you in the next episode
