The most important nutrient for initiating germination in virtually all seeds is water. The first
indicator that germination is under way is usually the emergence of the root. The root is
specialized for taking up water to continue nourishing the young sprout, so it is important for it
to be established first. As the plant continues to grow and develop, the shoot (stem and leaves)
starts to push upward. The starch or fat in the cotyledon supplies the embryo with the energy
and building blocks for growth during the first phase of the plant’s life. If all goes well, the
infant plant will soon form leaves, develop the pigment chlorophyll, and begin producing its own
food through photosynthesis.
Because we are animals and cannot produce our own food, we rely on plants to produce food for
us. One way we supply ourselves with food is to eat seeds. In the process we derive nutrition
from the embryo of the plant. Mostly we benefit from the food stored in the cotyledon, which
would have nurtured the developing plant right after germination and before photosynthesis.
When we eat grains, we are eating the starchy food supply of the corn, wheat, rice, or oat seed.
When we eat nuts, we are eating the fatty storage supply intended for the walnut, almond, or
peanut embryo. Beans are known as protein sources and when we eat them we are eating the
protein supply meant to drive hardy roots down to water and broad leaves to the sunlight the
emerging bean plant needs. Our bodies break down protein slower than sugar or fats, which is
why beans seem so filling—the energy stays with us for hours. All that protein takes up space,
which explains why bean seeds are so much larger than brassica seeds. Storing lots of energy in
a seed is one strategy to make sure a new plant is able to compete with other seedlings wherever
it is sown (smaller-seeded plants often demonstrate an alternate strategy: making lots more
small, energetically cheap, seeds).
Most seedlings send out their root first, followed then by their shoot. Cotyledons emerge and
open, followed by the first true leaves. The seed case sometimes falls off the top of the opening
cotyledon, or is left underground. These are predictable steps in the natural process of
germination: a pattern of nature that helps us to understand that all plants are related.
bean: small round kidney-shaped or round seed that is eaten as a vegetable and can be dried to
preserve.
germination: the sprouting of a seedling from a seed.
sprout: the upward growth of a new seedling; a stem, with its cotyledon(s) attached.
shoot: same as sprout.
root: an underground plant part that absorbs water and nutrients from the soil.
cotyledon: also called seed leaf; the first leaf or pair of leaves produced by a germinating
seedling.
embryo: an undeveloped plant contained within a seed.
seed coat: the tough, weather-resistant outer covering of a seed.
energy: the ability or power to do work
