Seed Germination biology lesson for kids: 1st, 2nd, 3rd, 4th, 5th, 6th and 7th grades biology lesson.
Most plants grow from seeds. Seeds come in many different shapes and sizes, and are like little plant eggs in a sense. Each one has all the nutrients (like carbohydrates and proteins) that a little plant embryo needs to start growing. Unlike eggs, though, seeds stay dormant until they find a suitable place to start growing. This growth is called germination.
Every seed has either one or two cotyledons. A cotyledon is a fleshy “seed leaf” where it the embryo’s nutrients are stored. Most plant species have only one, but a few species of plants have two. The seeds with one cotyledon store most of their nutrients in another, bigger, part of the seed called the endosperm, while those with two cotyledons store most of their nutrients in the cotyledons themselves.
As we all know, seeds are found inside fruits. The main job of the fruit isn’t to provide food for animals like us. Instead, the plant grows fruits so that the seeds inside can be scattered far and wide. Whether it’s by animals, winds, or water, eventually the seed finds a place where it can start germinating.
When the seed at the right temperature, and gets a good supply of water, it can start to germinate. Some seeds, like those that live in cold, northern environments, need cold temperatures to start growing. Others need the warmer temperatures of spring. Whatever the case, the seed absorbs as much water as possible when the temperature is right, and its cells start to swell.
The water also activates enzymes needed for the seed to ‘wake up’, and dissolves the nutrients inside the seed so the seed can move everything to the growing embryo. It also softens the seed coat, the protective layer around the seed, so that the new growing plant, which is called a seedling, can burst through it as it grows.
The roots are the first things to grow. The growing seedling uses these new roots to absorb as much water as possible. Then, the shoot starts growing. The shoot keeps growing as tall as possible until it finds light. Since the seed is often underground, this is important, since it allows it to break through the surface of the soil and increases the chance of it reaching light.
Once the seed finds light, it starts changing. It turns green, and starts growing leaves, so it can start making its own food, and eventually stop depending on the cotyledon or endosperm for its nutrients. The new seedling grows towards light, so that it has the best chance of getting as much light as possible.
If conditions remain suitable, the new plant can grow big and tall, and then one day make flowers of its own, which will then develop into fruits with tiny seeds to begin the process all over again.