Nearly every plant you see around you, from the blades of grass to the largest trees, came from a seed. When a plant reproduces (that is, when it has its babies), it puts them in a hard capsule along with enough food for them to live on and grow until they can start making food for themselves. Now, the seeds from different types of plants are also very different from each other; some seeds are as tiny as the head of a pin, and some are as large as a grown man’s fist—the largest seed in the world is from a palm tree called the Coco de Mer, is 15-20 inches in diameter, and can weigh up to 60 pounds! However, every seed no matter its size has to have three things: 1) the baby plant, called the embryo; 2) a food source for the embryo to use until it can make its own food (this is sometimes called the endosperm, or sometimes the cotyledons, depending on the type of seed); and 3) a hard shell to protect the embryo, called the seed coat. If we could look inside your bean seeds, we would see these things.
The embryo will use the food in its cotyledons and begin growing.
Here's what you'll need:
1. 10 Bean seeds
2. Paper towels
3. 2 small plates
4. A journal to write down all your observations
Here's what you need to do:
1. Take two paper towels and soak them in water. Lay them flat on a plate, one on top of the other.
2. Fold the soaked paper towels in half.
3. Take five bean seeds, and place them at one end of the folded, wet paper towels.
4. Fold the other end of the paper towels over the seeds. Place the wet paper towels with the seeds on the plate, and keep them in a warm place (a sunny window sill would work very well).
5. Now take two more paper towels, and repeat the procedure from above, but this time do not get the paper towels wet! Put these paper towels and seeds on the other plate, and keep them in the same place as the seeds in the wet paper towels.
6. Check the seeds every day, making sure the paper towels for the first set of seeds stay wet by adding one or two tablespoons of water each day. After 5-7 days, there should be a small white shoot coming out of the seeds in the wet paper towels. This means they have germinated!
How long did it take your seeds to germinate? When the seeds germinated, what did they look like?
What do the seeds in the dry paper towels look like? Did they germinate? Why or why not?
Be sure to write down all your observations!!
MAKE UP YOUR OWN EXPERIMENT!
What else could affect the plants’ germination? They must have water and warmth, but what about nutrients? If you added a little sugar to the water you use to soak the paper towels, would they germinate faster? Try the experiment again using different liquids to soak the paper towels (try sugar water, soda, coffee...be creative)! Be sure to germinate a few seeds in water alone too, so that you have something to compare your test to. Also remember to write down all your observations in your journal!