How Do Seeds Become Plants?

Some seeds are carried on wind currents before growing into new plants.

Plants that botanists call "seed plants" include all those that produce true flowers, and the conifers (like pine trees). Strictly speaking, the conifers are not flowering plants, but they do produce seeds and so they are seed plants. Not all plants grow from seeds. Ferns and mosses, for example, produce spores and have quite a different means of reproduction.

Seed Production

Seed production begins with the male flower or cone, or the male part of a single flower, generating pollen. Then, either by wind, insects or other means, the pollen is transferred to the female flower or cone and pollination takes place. The pollen then fertilizes the egg within the female flower or cone and an embryo forms. (Yes, it comes as a surprise to some but in botany the terms "egg" and "embryo" do apply.) The embryo grows and develops into a mature seed, complete with the whole complement of DNA necessary for growth and development of the mature plant.

Seed Dispersal

In the plant kingdom various strategies have evolved for the seeds to be scattered or carried away from the parent plant. As with pollination, this can occur by wind. Pine tree seeds, for example, have a wing that helps them to drift away from the parent tree. In a strong wind the seeds can be carried long distances. Other kinds of plants have developed other means of seed dispersal. Oak trees benefit from the services of squirrels, because not all the acorns that a squirrel buries are found and eaten. Another example would be the seeds of crop plants being dispersed and planted by humans.

Germination

After seed dispersal, in nature it's often a matter of chance that the seeds will end up in a favorable setting. Some will perish but others will land in conditions that promote germination. Germination is the process of the seed coat opening and the new plant beginning to grow. Adequate moisture is very important for germination. Once the emerging plant has escaped the seed, a root forms and penetrates the soil and a shoot or stem grows upward into the light.

Growth

If conditions remain favorable and the young plant is not eaten or otherwise prevented from growing, it will continue to develop. Once it has become a mature plant it will eventually flower, or produce cones in the case of a conifer, and will be well on its way to production of seeds of its own.

New Generation

A new plant that has successfully germinated, grown, matured and produced seeds has completed one generation of its kind. Of course, nature being what it is, the cycles continue and repeat indefinitely. New seeds become new plants through the stages of development at each turn of the cycle.

References

• Washington State University: Seed Germination
• "Botany---An Introduction to Plant Biology, Fifth Edition"; T. Elliot Weier, C. Ralph Stocking and Michael G. Barbour; 1974