In part two of this gardening series, Everyday Einstein talks about germination.
Germination has always seemed a little magical to me. You have this tiny rock-like thing that can sit dormant for years, then you stick it in the ground, give it a little water, and in a few days you have a plant--just like magic.
But of course, it isn’t actually magic. So let’s take a look at some of the really amazing things that happens to a seed during germination.
Parts of a Seed
Plant seeds have a lot of cool stuff packed into a tiny package. First, you have the seed coat, which is the outer covering of the seed. Not only does the seed coat protect the delicate internal parts of the seed, but it also serves as a sort of sensor system to let the seed know when it is time to germinate.
Inside the seed coat we have the plant embryo. This consists of the seed leaves, or cotyledon, which we learned about last week; the radicle, which will form the the root of the plant; and the hypocotyl, which will form the stem.
You might wonder why scientists couldn’t have just named these things the "baby root" and "baby stem." Is it because they just like to make things difficult for biology students? Actually it’s because science has a tradition of naming things in Latin and Greek. (Occasionally, there is some French thrown in there, too, because French used to be the language of science.) This might seem annoying, but on the bright side, if you study a little Latin and Greek, you’re almost sure to see a dramatic boost of your science vocab scores on any test!
The final part of the interior of the seed is the endosperm, which provides the food for the plant embryo when it first starts to grow.
Take off Your Coat and Stay a While
In order for germination to occur, certain conditions have to be met, and those conditions vary from plant to plant.
Some seeds will only germinate when water is absorbed through their seed coat. Others will germinate once the seed coat has cracked due to extreme heat, like in a forest fire. Still others won’t germinate until they have experienced sufficient sunlight.
All of these mechanisms serve to help the seed have the best possible chance of survival. For example, the seed of a tree won’t have much of a chance for survival if it germinates under the darkness of a thick forest canopy. So it stays dormant until it is exposed to sufficient sunlight.