How Pollen Works

For about 375 million years, plants have been using pollen (aka plant sperm) to propagate their species. And the technique has stuck around because it works. Join Chuck and Josh for a cozy look at the ins and outs of plant reproduction.

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Episode Transcript

Speaker 1 (00:01):
Welcome to Stuff you Should Know from House Stuff Works
dot com. Hey, and welcome to the podcast. I'm Josh
Clark and there's Charles W. Chuck Bryant, and that means
it's time for stuff you should know that itchy screezy
seezy scratchy addition, not scheezy. No, that's not itchy scratchy

(00:26):
sneezy edition. That's what I mean. There you go. It's
funny how you can mix words together come up with
other words. You didn't mean to say, Jerry's eyes are
at itching. Yeah, well we should say. We were just
talking about the pollen count here in Atlanta. That's pretty
much all we ever talked about. Ever when the camera's
not honor that mikes aren't recording that in Coca Cola.

(00:47):
Oh you know how everyone comes to Atlanta and they're like, oh,
every street's named Peachtree. Let's go drink a coke because
so's the only two things we've ever had. Alright, Sorry,
that's fun. So you want to talk about pollittin Moore
it's low right now in Atlanta thirty nine that's moderate. Yeah,
well low for us, right, but like according to the
pollen scale they scale that they used to count pollen

(01:10):
and then designated somewhere along the pollen spectrum. Thirty nine
is considered moderate, not even low moderate. When it's really
bad here in Georgia, it gets to about nine thousand.
Those are the few weeks that the the streets run
yellow with. When it rains with yellow water, it looks

(01:30):
like p yep, your car is totally covered in it.
You're covered in it. It's just everywhere everywhere. Yeah, but
now we're about to tell everybody we're basically going to
turn everybody into a palenologist. Yeah, to an extent, should
be a big fan after this an amateur palenologists. I
think about a third of all the plants and vegetables
and fruits and vegetables we eat, are you know here

(01:52):
thanks to pollen. So if you like eating food, yeah,
it doesn't come in a box, thank you pollen. Is
it just a third that pollinate or a third that
are just angiosperms or gymna sperms? That wow, what's up
with the other two thirds? Well, you know, bananas, they're
clones of one another. There's like that, there's the one.

(02:15):
There's like I think a thousand varieties of bananas, And
thanks by the way, to damn interesting for this information.
But there's like a thousand varieties or species of bananas,
but each one, like if you eat like a type
of just one of those species of bananas, you're eating
an exact clone of every other banana in that species,
because many thousands of years ago, humans just stumbled upon

(02:37):
the banana, which is the hybrid of two basically inedible
fruits that came together to form the delicious banana, but
made them sterile. All banana plants are sterile, and the
only way that they're allowed to propagate is by human hand.
They're delicious. I did a Don't be dumb about that? Yeah,
well you just did it again. Yeah, you can check

(02:58):
out Don't be dumbs on our website Stuff you should
know dot com. Wow, all right, anyway, pollen, Yes, it's
been around for a while. Um. I know. In our
b podcast we talked about how bees and and pauling
kind of emerged side by side a hundred million years ago,
but Paullen actually goes further back than that. In this article,
it says about three five million years ago is when

(03:20):
the plants started getting clever and spreading their seed literally
using pollen different techniques, and I think the um the
gymnast sperms were first, I believe so. Uh yeah. And
the author of the article here points out that the
reason why it evolved was so plants didn't have to

(03:41):
be dumb and rely on water to carry their junk
to fertilize other junk. You know, they're like, how about
wind or how about that bat a beetle? Yeah, or
how about that bird pooping it out? That's right? Yeah? Um?
And like I said, I think Paullen Green's plants spread
their seed. Literally, plant pollen is what amounts to plant sperm. Yeah,

(04:06):
It's like I always go to the kids science pages
to research. First off, I mean they're good, they're they're colorful.
Uh yeah. If we want to pollination very simply, you know,
people reproduce. Animals reproduce, they need male and female parts.
Plants and flowers are no different. They need male parts
to connect with the female parts to make an egg.

(04:27):
And in this case, pollination is how it's done. Basically,
how that sperm, the pollen reaches that egg, which is
the ovule, right, and once they get together, magic happens.
That's right. But let's talk about the way it looks
first of all. Yeah, there's like there's a lot of
different looks to pollen depending on the plant um and

(04:47):
all of these variations. It can be like a cone
literally a pine cone. Yeah, it looks at you know,
just look up microscope pollen on Google Images and you'll
see all sorts of weird colorful shapes and sizes. Some
look like blowfish. Yeah, others look like spot nick really yeah,
I didn't see this spot Some have ribbed edges for

(05:11):
and all of these adaptations are or mutations, I guess
they became adaptations allow that pollen to kind of better
ensure that it's going to be carried to where it
needs to go. Yeah, it has a purpose. It's not
just like, hey, this one would look neat if it
looks like a starfish in the end. Some have wings
kind of what amount of basically wings because they're carried

(05:34):
on the wind. Oh yeah, yeah, like dandelion pollen, it's
carried on the wind. True. Well, dandelion's self polling night too.
We'll get to that though. Yeah. They're slippery little guys.
They are. They're also high and phytonutrients as well. Yeah,
dandelion greens are O the stems, No, the leaves, oh,

(05:57):
the little leaves, the yellow part. So here here's the
rule of thumb. There's a New York Times article that
came out very recently about phyto nutrients and how we
basically bred them out of our food, and um, the
rule of thumb is the the bit, the bitterer or
more bitter the plant, the higher it is in phytonutrients.
Phyto nutrients have kind of a bitterest, stringent taste, and

(06:20):
we tend to not really like that, so we stopped
eating those things over time, replace them with sweet things
that aren't necessarily good for us, like you know, potatoes
and other starches. Ye, well, bitter things can also kill you,
that's probably why. Maybe, So that's that's a pretty good point.
But bitter stuff that you know won't kill you. Dandelion
leaves go out and needs some right now. But back

(06:42):
in the day, I bet people are like that tastes
bad and it killed tuk tuk, So let's just not
eat it right exactly? Alright, So should we talk about pollination?
Talked a little bit about pollen. Yeah, now we need
to talk about how plants make little baby plants, right,
and it's it's pretty simple, like I said, the male
part and have you. Uh, it really helps to follow

(07:05):
along if you go to a handied andy little visual
aid I found, because they really break down the male
parts and the female parts. The female is the has
the pistol and that's p I S T I L.
And within that you have the ovary, which are you know,
sits down low in the plant, and the style which
is a long ah thin h appendage. I guess that

(07:30):
contains pollen tubes. And then at the top you have
your stigma, which is gonna catch the pollen. Yeah, and
that's the female part, right, that's the lady. Don't be
confused because it is phallic in nature. Yeah, true, but
it's still the female part. And the male has the
filament which is a long stem, and then the anther
at the top which holds all the pollen. And that's
pretty much the long and short of the parts. And

(07:53):
is that just angiosperms that you're describing or is that
all all? I think these are just the and a sperms. Well,
we should say quite explicitly that there's basically two ways
that plants can pollinate. There's gymnasperms and angiosperms, And the
big difference between the two is that gymnasperms literally that
means naked seed, which, by the way, gymnasium is means

(08:16):
place to be naked canasium in German. Did you know that?
So gymnasperms naked seed. There's nothing protecting the seed once
it's once it's produced, and a seed is just a germ,
a fertilized ovum or ovule, right um, Angia sperms produce
something to protect that seed, whether it's a shell like
a nut or fruit like an apple with the seeds inside,

(08:40):
because an apple is just a an enlarged ovule ovary
and the seeds are the fertilized though. Well, you can
also pollinate, across pollinate or self pollinate, right, those are
the other two differences. So you're saying, what what dandelions
self pollinate? Well, they can do both, um, but do

(09:00):
have a little a cool little feature. They basically grow up.
You know, this is when there's still the little yellow flower.
They have these little florets that grow up. If you look, well,
you probably can't see if you look really really close, though,
these little florets that grow up and as it grows
it carries uh, the pollen on its little stem and
then eventually gets to a point where it doesn't start

(09:22):
grow growing up anymore, and it splits and then starts
curling back on itself to uh, you know, no way.
It picks up its own pollen from its own style,
and it's self pollination. It's not gross or like perverted.
There's a there's a lot of them. There's a lot
of plants out there though, that have mechanisms to prevent

(09:45):
them from self pollinating. It couldn't can't be good or bad.
That's what I couldn't figure out. Well, the plants somewhere
along the way figured out like, hey, the wider the
gene pool, the better off we are, because the more
room there is for adaptation mutations and than adaptations. Right. Yeah,
But in here the author said ideally it cross pollinates.
But I don't think that's the case always. Well, it's

(10:06):
the ideal, it's just some doing some don't write. I mean,
if you look at it, like from just an animalistic
or an organism viewpoint, right like with us, if you
just get a bunch of Mennonites together and they just
reproduce with one another, there's going to be defects that
just are propagated throughout this this little gene pool. But

(10:26):
if the Mennonites spread out into the you know, larger
country as a whole, those defects are going to you know,
I guess we kind of watered down by the size
of the gene pool. I think it's the same thing
with self pollinating and cross pollinating. Yeah, because it's interesting
because things like peanuts or self pollinators and that's why
they thrive. But corn has a mechanism to not allow

(10:51):
itself to self pollinate. Like there. I think the sperm
is ready at a different time than the ovule is
ready to accept it, So it's it's a timing thing.
The thing is, peanuts would probably be able to talk
if they didn't self pollinate, and they sound like Jimmy
carter um. So there's a lot of mechanisms that plants

(11:12):
have to prevent themselves from self pollinating. Um some. Some
might have either just male plants and just female plants.
UM some maybe uh where the male part if the
plant has both male and female flowers, for example, yes,
they they the the male flower might come out before

(11:35):
the female flower on the same plant, so that they're not.
The timing is off a little bit. Um, and then
there's some they're just like they'll they'll signal a biochemical marker.
If pollen from the same plant gets near the ovule,
it'll just basically turn barren. So it just is incapable
of fertilizing itself, or like corn where the timing is

(11:56):
thrown off. So they rely on cross pollination, right, which
is pretty cool. So let's let's get explicit again here
gymnaspers naked seed. How does this happen? Like it? We'll
use the example of a pine, a lob lolly pine.
It's fun to say, um, but it's a conifer. Conifers
are ancient. I believe they were the first pollinating plant. Yeah,

(12:19):
I think so. Nice. So let's talk about it. Well,
the pine cones, they're they're little male pine cones, a
little female pine cones. Might not realize that you've got
quite a show going on in your backyard at certain
times of the year. Um. And basically, if once you
get the two together, you get a male pine cone
and a a female pine cone together, the male pine cone fertilized, well,

(12:42):
the pollen comes in contact with an ovule and the
pollen starts to go to town. It absorbs a bunch
of water. Well, the female pine cones a little sticky too.
That helps, by the way, it does, helps collect the pollen.
Right um, So the female or the the pollen, the male,
the male part of the pine cone germinates and it
starts growing. It's called a pollen tube, which basically allows

(13:04):
this pollen to directly fertilize the ovule. Once that happens,
the ovule basically becomes a seed, and the seed is
released from the pine cone. They go everywhere and then
they're eaten by birds and pooped out elsewhere, carried along
in the there trampled by a rhinoceros who knows which
just got loose from the zoo. But then that seed

(13:27):
is carried along, but it's not protected by anything. It's
just a seed and hence a naked seed. Hence gymnasperms,
So angiosperms, they have kind of like a similar process,
whereas there's a pollen tube that's grown and the male
pollen has to come in contact with the female pollen
and all that. And we're talking about flowers in most

(13:47):
cases here with andrew sperms, they're the only ones that
flower and produce fruit. So when you think about your
garden with the honey bee and all, that's right. So
that's a non naked seed and that's the that's where
the fruit comes in or the shell comes and there's
Andrew's firms have developed a mechanism to protect the seed

(14:08):
to better ensure survival and if you think about it,
to entice the things that transport these seeds to go
ahead and do their thing. Yeah, there's like every flower
has some sort of cool shape or scent or color
or something that matches with some little insect or bird

(14:29):
or bat that's gonna be enticed. Like the bumblebee in
the fox glove, they go hand in hand because it
fits up. They're just perfect. And it has a little
colorful landing strip on the bottom pedal to guide the
bumblebee in and it's just like nature's it's just like harmonious.
There's that one orchid that I believe Darwin predicted the

(14:50):
existence of a type of hummingbird that had a very
long curled beak right that it co evolves with it,
and he was absolutely correct. Members in that movie ad Yeah,
that's a great movie. Um, and then uh, you can
learn a lot from that movie. Yeah, yeah, anything that
what's his name? Charlie Kaufman writes, well, researched um. The

(15:12):
fruit is another thing too. Animals love to eat fruit.
The fruit is basically once the fruit piece of fruit
drops to the ground, that means those seeds are ready
to go. They're ready to become seedlings. But first they
need a fox to eat the apple, carry it in
its stomach over you know, several meters or miles or whatever,
and then poop it out. And then you have seeds

(15:35):
that are basically just planted. That's amazing. They take purchase
and a new tree begins where his seed her insides
where a rocky place where seed you can find nor purchase.
So pollen grains um are actually created. I guess we
should step back a second and talk about myosis. That's
the cells are dividing and growing. Eventually you get a

(15:58):
little pollen. Uh, it looks like a little dust spec
to our eyeball, but it's contains the sperm. Is not
actually the sperm. It contains the sperm therein and uh,
the pollen is in pollen sacks at the end of
the stamen, which we talked about and that little two
lobed ant uh almost at antler antherer and then eventually

(16:20):
it'll find its way to the stigma and travel down
to the ovary. And and in the case of angiosperms,
there are two sperm that are used. I don't think
we said in the case of gymnosperms, it's only one
of the sperm is used, right, Yeah, in a in
a pollen sact, there's two sperm, but you just need
one for the gymnasperm for the anti sperm unit to yeah,

(16:40):
because one is actually fertilizing the egg and the other
is developing into endo sperm together alongside and what will
eventually be the seed. And if you think that sounds gross,
like the gymnos sperm, I'm sorry. The endosperm is like
a protein basically to keep it all alive. Yeah, that
keeps the seedling happy, healthy. So when you're eating corn,

(17:03):
you're actually eating the indo sperm. Each corn kernel is
actually you know, it's like that starchy indo sperm which
the seed loves to eat itself. And that's true. Um,
So we talked about bees, we talked about birds, foxes,
mentioned poop a couple of times. Yeah, and you were
saying that, like basically every every flowering plant especially has

(17:27):
some sort of mechanism to attract at least one kind
of um bug or animal that's been proven to help
pollinate transport this pollen. And so I mean, for the
most part, we enjoy them, like you like the scent
of you know, a good flower, right, sure, but you

(17:47):
might not like the Devil's Tongue, yeah, which is a
sumatran plant that apparently reads so badly smells like a
decomposing flash. Basically, basically, did you this thing? I've seen
it before. You actually remarkable like two feet and it's
it's like it it basically um flowers or blooms like

(18:08):
once every like ten years or twenty years something like that. Right,
I'm not sure if it's the same one I'm thinking
of things, but it's sink right, And the reason why
it's stinky is because it pollinates with the help of
a type of carrion beetle that's attracted to decomposing flesh.
So the plant attracts this beetle that likes to eat
decomposing flesh by putting out the smell of decomposing flesh

(18:32):
that's so gross. Yeah, but it's pretty spectacular. It is,
you know, yeah, in the philodendron, something you might have
in your house. It actually does the same thing, but
it doesn't stink always. Um. There's actual chemical reaction that
takes place and heats it up to omit this odor
that the beetle is attracted to, which sounds pretty gross too,
but it all works, and I would google that. Um

(18:54):
the sumatra and devil stung. It's pretty cool looking. Like
the flower itself is two feet It's not like, oh,
what a long stem, it's just as huge flower. It's amazing.
And then you're also saying, like, was it foxglove that
provided a landing strip for bumblebees? Yeah, So flowers in
general typically have certain types of um like their color

(19:15):
will be based on the kind of creature that um
that that helps pollinate it, whether it's diurnal meaning it
it's awake during the day or nocturnal meaning it's awake
at night, right, right, I guess that's in case of
like bats and stuff like that. Yeah, and then our
old friend nectar is a big lure and basically nectar
is around right just because it tastes delicious and is

(19:38):
enticing from Yeah, it's basically like a little enticement like
you said, for like a bee or something or a bird. Yeah,
come get it, because it's placed by the stamen that's right,
or the way that the the anthers are situated, just
the way they're placed in the flower. If it gave
it an advantage to bump up against that bee, then

(20:00):
it's gonna be successful in the long run and live
out as a species as nice stuff. That is pretty good. So, Chuck,
we've reached a point where, um, I mean, ever since
we started selectively breeding plants, domesticating crops that's pretty right.
Or hey, I like this banana um or that's hardy
and it grows in my awful hot area that I

(20:21):
live in. Many reasons to do so, right, Um, you know,
we we wanted to keep plants, We wanted to keep
the bad stuff out, keep the good ones we wanted in.
But it never became more crucial, um until we started
genetically modifying crops. And now all of a sudden, not

(20:42):
only are the corporations saying like, hey man, you can't
cross pollinate with our stuff for else that's patent infringement,
and nearby farmers says I'm not using your seeds as
the bees. You can't blame me. And the farmers who
don't want to know most stuff in their crops say,
hey man, you need to keep your crops over there
because I don't want your GMO crowd in here. I

(21:04):
have an organic farm exactly, and you're just blowing by
the wind. It's a touchy subject. We should do that.
It's I agree. The idea of like patenting jeans in
general and they alone like crops is it's really interesting. Um,
but there's been some pretty clever, simple ways of getting
around this problem. It's posed by pollination of GMO crops

(21:28):
with non gmo crops. Yeah. Well, distance is obviously one thing.
Don't put my farm near your farm. But they have
to do all kinds of studies to see how the
wind reacts and how like how far does that be fly? Yeah,
and they found in uh, in certain parts of Africa,
these will go about four miles three kilometers that's their

(21:49):
range for food. That's you know, that's a lot. But
I mean, just using that kind of thinking with all
process though, like okay, well this you know, there's this
guy's growing this over here, so I can't of this
here right, That will prevent that kind of pollination though. Yeah.
Another thing they can do is, uh, sort of like
with the corn, they can time their crop rotation to

(22:10):
time out so where they're flowering at different times and
not interfering with one another. But um, it's a touchy subject.
Like from what I understand, there's a lot a lot
more going on then you know, is preferred by like
the organic farmers of the world, and in't the GMOs.
They can then say that you're infringing just because they

(22:32):
cross pollinated to their crop, even though you didn't buy
their seeds or even want their seeds. If a bee
carries there, there's seeds, there's crops falling over to your crops,
and you start to develop plants that have the characteristics
that's patented. According to the corporations, you're infringing on their patent.

(22:55):
It's very tricky ground, there isn't it. I don't think
it's triggy ground. If you ask me, you should not
be allowed to have a patent on any living organism. Yeah,
you know what I mean, though, that's my opinion. It
gets tricky, uh in courts and studies and corporations, and
of course they tend to side on the corporation's side. Typically.

(23:16):
Let's do that one though soon GM. Yeah all right, Um,
so let's say, for Paullen, if you're interested in how
pollen causes allergies, and you should listen to our how
Allergies Work episode. That was pretty good. Ye I was
gonna recommend that. Nice work. Um, thanks man. So, uh,
if you want to learn more about pollen in the meantime,
you can type that word in the search bar how
stiff works dot com. Since I said search bar, it's time,

(23:38):
of course for a message break. And now how about
some listener mail. Yeah, uh, whip correction. It's been blowing
up lately. Oh man, I'm sorry. You know it's craziest.
That's the second time I've done that, and a podcast
on that same same thing. I don't remember what the

(24:01):
other podcast was, but I've mentioned it before and we've
gotten tons of corrections about it, and I didn't learn
my lesson. Well, this guy was really nice about it,
so I'm gonna read his. And it's an important correction
because anytime you're talking about drugs. So to recap in
the PTSD podcast, we got the two drugs beta blocker,
called propan and all, which helps with PTSD, confused with propofol,

(24:25):
which is what killed Michael Jackson. And so this is
from Chris. He's a big fan. He's listened to every
episode on his commute in southern California, which we know stinks.
So he said what we just said about the getting
the drugs confused. He seconds, see how you guys can
mix it up because the names are very similar, but
they're significantly different. Obviously, propan and All is relatively mild

(24:49):
and um commonly prescribed, and very little potential for overdose,
while propofol is a very powerful drug, extremely high potential
for overdose, and rarely administrated outside of strictly monitored medical settings.
It is actually a hypnotic agent that must be administered intravenously.
Because we talked about Michael Jackson's drip. Uh and is
often used in conjunction with general anesthetics. Like most general aesthetics,

(25:13):
it's steep dose response curve significantly increases the risk of overdose,
where the effective dose is only slightly below a lethal dose.
That's kind of scary, Yeah, it really is. I mean,
like when you're when you're on that, like you're right
along the border. Yeah, Well, he says, Michael Jackson's case
is extremely rare, as he was essentially exposing himself to
risk similar to those associated with general anesthetics used during

(25:36):
surgery with a higher potential for overdose and death on
a daily basis for a relatively trivial purposes, which were
in this case is insomnia. Yeah, but from what I understand,
he had like years long insomnia. Like this guy was
not sleeping at all, Like they would they wouldn't. They
would give him everything first and then they try that

(25:58):
last resort and like sometimes it's still wouldn't work. Really, Yeah,
he was really in bad shape at the end. Well,
he probably had a resistance to certain ship things like that.
Uh So, Chris goes on to say, I'm not certain
about the exact amount of risk posed by propofile administration,
but I believe the risk of death is something on
the order of tenths of a percent, meaning he would

(26:20):
have died according to the statistical model, within a couple
of years of daily use, like British guaranteed. Frankly, he
would have been better off using heroin that whole time.
In spite of his ironically strict yet poorly informed anti
drug stance. So that's from Chris. Thanks Chris, that was
a genuinely awesome email. That was good. Um, and I'm
sorry everybody freaking so wrong. Well, I mean the names

(26:43):
are just confusing, yeah, but I mean one's like a
blood pressure medicine. The other one's like pretty much a
general anesthetic. I know. But what gets me is that
half of the emails were like, well, yeah, they just
sound alike, so you cooke did it in Half of
them were like those drugs couldn't be any more different,
like you really thought that, you know. It's just it's
like a verbal pipeo and key chuck. Yeah, thanks for

(27:04):
letting me off anyway. Uh, if you have a correction
for us, we really do like to get those. We
like to know what we're talking about. Sometimes we get
we get things wrong, sometimes I get things wrong, but
we do want to be corrected in the nicest way
possible because that's usually who gets their letter read right exactly. Yeah.

(27:25):
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