Part 1 - Introduction
After the first lesson, we now know all the parts of a plant; how, after growing awhile, the plant blossoms; that the flower gives rise to the fruit; that the fruit contains a seed; and that the essential part of a plant inside the seed, is the germ, or embryo. We know that the purpose of a flower is to produce, protect and nourish the germ; and the purpose of the germ, is to grow and become a new plant. In this section, we will learn how the germ grows into a new plant.
Part 2 - Life inside the seed
It is important to know that seeds may not always grow immediately. They lie where they fall, feeling neither the winter's cold or the sun's heat and slumbering away until the spring (in most plants), or sometimes the spring after that, before it begins to grow.
Although alive, some seeds might show no signs of life for many months or years. Red maple seeds ripen in their first spring and start growing in the middle of summer. Sugar maple seeds ripen in the autumn, but lie quietly until the next spring. When gathered and kept in a dry place, seeds may keep for 2, 3, or several years. In this state, they can be safely transported all over the world.
How long seeds will live is uncertain. The stories of seeds growing, which have been preserved for 2000 years or more with Egyptian mummies, are not to be believed. But is well know that plants have been raised from seeds over 60 years old!
However, few kinds of seeds will grow after keeping them for 5 or 6 years. Many refuse to grow after their 2nd year; and some may not grow at all unless allowed to fall to the ground at once. There is no way of telling if a seed is alive and will grow, except by trying to germinate, or grow it.
Part 3 - Germination and early growth
Germination, is the sprouting of a plant from a seed.
In the first lesson, we met the parts of a morning glory plant from its root, to its stem, to its flowers, to its seeds. We even met the embryo inside its seed. Today, we will use the morning glory again, to see how a plant grows from its seed.
Let us imagine ourselves planting a morning glory seed. Let us cover it gently with soil, water it well, then place it somewhere warm to grow.
First, the seed swells as it absorbs water through its shell; then the warmth wakens the embryo inside from its long, deep, sleep and it stretches out its limbs.
The tiny stem, or radicle, lengthens and bursts through the seed's coat. At the same time, the two little leaves, or cotyledons, grow larger, stretch themselves, and burst open, throwing off the seed coat.
