B2 中高級 8924 分類 收藏
So, the apocalypse has happened.
The zombies have come and gone,
and all plant life on Earth has died somehow.
All you have are some basic supplies
and some seeds of a few types of essential plants.
So, what should you do
to make absolutely sure they grow,
seeing how rebuilding human civilization
absolutely depends on it?
Well, you'd probably think
the last thing you should do
with these crucially important seeds
is something like poking holes in them,
or grinding them with sandpaper,
or throwing them in acid
or hot water.
But, in fact, all of these are methods
that are commonly used
to help seeds start growing.
A typical seed consists of a plant embryo
encased in a hard seed coat.
To start growing,
it needs to emerge or sprout
from inside this shell.
This process is called germination.
But just as it would be hard
for you to get out of a jail cell
with no windows and no doors,
the embryo might need a little help
escaping from its seed prison,
and any process that makes this easier
by wearing down the seed coat
is called scarification.
This lets moisture and nutrients
get through the seed coat,
making the embryo start growing
until it breaks through.
Now, you might be wondering
why it is that plants would need humans
to do all these weird things to their seeds
in order to grow,
and, in fact, they don't.
In natural environments,
seed coats are worn down by cold temperatures,
or even animal digestion.
Our scarification methods just mimick
and accelerate these natural processes
to increase the chances of successful germination.
One technique we can use is called nicking.
To do this, we make a small cut or scratch
into the seed coat.
Be careful not to cut too deep!
You don't want to damage the plant embryo inside.
Another way is to file down the seed coat
using sandpaper or a nail file.
Once again, you don't want to file too much,
just enough to wear down some of the seed coat.
After applying either of these methods,
you'll want to spray the seeds with bleach
to prevent mold.
Seeds can also be soaked in water
to soften the coat.
One way to do this
is to place the seeds in a nylon bag,
then place the bag into hot water.
Turn off the heat immediately
and allow the water to cool to room temperature
before removing the seeds.
It's important not to heat the seed for too long
as this will kill the embryo.
Again, you'll want to spray them
with bleach afterwards.
Finally, you can try immersing the seeds
in a sulfuric acid solution.
Make sure you're wearing protective goggles and gloves
any time you work with such a dangerous substance.
Place the seeds into a wire mesh pouch
and immerse the pouch in the solution for ten minutes.
Then take out the pouch
and rinse it with clean water.
Take out the seeds and, as before,
spray them with bleach so they don't get moldy.
If you try all of these methods,
you will see that some of them
are more effective than others,
and some work best for different types of plants
that have harder or thicker coats.
So, knowing what seed scarification techniques work best
will be useful if you ever need to survive a cataclysm,
start a farm,
or just want to plant in your own garden.


【TED-Ed】要種花了嗎?用些漂白水、酸和砂紙吧 (Got seeds? Now add bleach, acid and sandpaper - Mary Koga)

8924 分類 收藏
VoiceTube 發佈於 2013 年 10 月 13 日
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