Plants try to reproduce by producing seeds and distributing them all over the place. Most of these seeds usually do not survive, but some seeds land in areas where the conditions are right and subsequently grow. The process of seed development and germination is very complex and contains many different processes.
Seeds develop from the ovules of the female reproductive organs of plants. Ovules must be fertilized by pollen to be able to develop into seeds. The ovary gets increasingly bigger, but the seed is usually not visible in the swelling ovary, according to The Seed Site, a British website devoted to seeds. The seedpod does not become hard right away but instead remains soft and green. The seed develops a protective coating and changes color. The production of seeds requires a lot of energy for the plant, so dying or weak plants might not be able to fully develop their seeds and the wasted seeds will instead drop so that the plant can preserve its energy.
The ovary sometimes ripens and produces a fruit that has a sweet smell and taste, according to The Seed Site. These fruits are meant to attract animals that will eat the fruit, swallow it, and then drop the fruit seeds or pass the fruit through the digestive system. Since the seed will be mixed into the feces of the animal, the seed will already have fertilizer, according to James Madison University.
The seed contains an endosperm that provides nutrients for the plant embryo when it develops. Because of this, seeds are able to survive for a long period of time without growing, according to Clinton Community College.
A cotyledon provides the plant with sugars that it will need to grow after it has emerged from the seed, since the plant will not be capable of engaging in photosynthesis, according to James Madison University. The plant can use oxygen to break down sugars similar to how animals can break down these sugars.
The seeds of the conifers -- plants that produce cones and have needle-like leaves -- are naked and are produced within cones, according to Clinton Community College. Inside the cones are ovules, which are fertilized by the pollen grains. They develop four megaspores, three of which die. The surviving megaspore develops into a very small gametophyte, which produces the eggs that eventually turn into the seeds. Angiosperm trees produce flowers. These flowers release pollen and usually need to be fertilized either by distributing their pollen through the wind or by animals.