Seeds


Most plants I see are old enough
to have leaves, flowers, maybe even fruit. But even before they
poke out of the soil, plants look strange
and beautiful, and hold secrets
about their ancestry. Take this bean, which
I found in my kitchen. Get it moist, and
in a few days it has sprouted a
root– lots of roots. And wait a minute, it has
pulled out some leaves and left its seed case
just sitting there. And poppy seeds, which I just
sprinkled on a wet paper towel, sprout these long stems
with tiny leaves on top. Red popcorn, which somehow also
made its way into my kitchen, spreads just one leaf– sort
of like grass, but bigger. That sort of makes
sense, though, because corn is a
domesticated form of grass. Thousands of years
ago, people living in what is now Central America,
bred their local grasses so they would taste better
and be easier to harvest. So at this point I’m wondering,
what about other plants? And I set up lots of
moist paper towels with different seeds in them. Can we find patterns about
which seeds grow similarly? And guess which ones are
related to each other? Here’s the first
pattern I noticed. Cucumber seeds
first extend a root, then pull almond-shaped leaves
out of their seed casings. Pumpkin seeds are bigger,
but they grow the same way– first poking out a root, and
then pulling out their leaves. Do you want to see that again? Here are the cucumbers. And here are the pumpkins. And I looked it up,
and they are related. They’re both members of
the Cucurbitaceae family. That bean I grew also pulled
its leaves out of its seed, but its seed and
leaves look different from cucumber and pumpkin. Beans are in the legume
family, but it turns out another member of the legume
family grows quite differently. These circular
lentil seeds don’t get pulled out of their
seed casings to form leaves. Lentils, it turns out, extend
these small ragged leaves, and leave the bulk of
their seeds underground. I was pretty surprised by this. Somehow, even though beans and
lentils are in the same family, they face different
selective pressures and grow differently–
even as seeds. I looked it up, and it
turns out lentil seeds are called hypogeal,
which means underground. Actually, the red
popcorn is also hypogeal, even though the lentil
sprouts with two leaves– a dicot–
and the corn sprouts with one leaf– a monocot. So we can’t just look at
whether seeds are hypogeal or not to find out
which ones are related. But let’s look
for more patterns. Look carefully at how
these radish seeds grow. See the shape of their leaves
and how they pull them out of their seed? It may not look that
exciting, but now let’s look at how these
Brussels sprouts grow. Pretty similar, except without
the red color and the stalk. Now take a look at kohlrabi. Oh, they all grow
exactly the same way. These heart-shaped kohlrabi
leaves look the same as these heart-shaped
Brussels sprouts leaves. And these heart-shaped
radish leaves with their reddish stems. Actually, these three plants
are different domesticated varieties of the same
genus– brassica. No wonder their
seeds look similar. But I wouldn’t have guessed
it before I saw their seeds. How do you think these long
skinny seeds will grow? I think we’ll just
have to test it. Looks like they’re sticking out
a root and then pulling long, skinny leaves out of
their seed casings. Reminds me of how the
almond-shaped cucumber and pumpkin seeds pulled
out almond-shaped leaves. Perhaps that’s what
you would have guessed. But now I’ll show you
something I couldn’t have guessed before I saw it. It was so weird that it even
confused me once I saw it. How do you think these
beet seeds will grow? Let’s take a look. Wait, some of those seeds have
more than one root poking out. Some of them have more
than one set of leaves. How could that happen? I was really perplexed
by this, until I realized that each seed is actually a
clump of several seeds bundled together. That’s how each one
grows multiple saplings. I guess seeds can be
really unpredictable. I find myself collecting
strange looking seeds that I see outside. Look at these. They’re almost like a pine
cone, but with clumps of hair so each seed can go on the wind. Who knows how they’ll grow? But if we look closely at
how these seeds grow and look for patterns, we may be
able to uncover secrets about their ancestry
and relatives.

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