Seed is the primary means by which plants disseminate themselves and produce offspring. They contain an embryo and food reserves in a protective covering.
Gardeners can use various containers to start seeds, such as flats, trays, and cell packs. Previously used milk cartons and plastic jugs can also be used, as can paper cups and egg cartons. Some species of seeds require scarification, which breaks chemical dormancy and encourages germination. Stratification (moist chilling) is another method that can be used.
In botany, seed refers to an embryonic plant enclosed in a protective outer covering. Seeds are the primary means by which flowering plants disseminate their offspring and they are also the main way that grasses and grains propagate themselves. Seeds are surrounded by a food reserve called the endosperm, a stem known as the cotyledon and a hard husk or seed coat. A scar on the seed coat known as the hilum marks the spot where the seed attaches to its parent plant’s ovary.
Seeds are mainly used as a source of food, especially cereals, legumes, nuts and oils. They also provide the proteins that give bread its texture. In the Bible, the term “seed” is sometimes used in a more general sense of descendants; e.g., in Genesis 1:18; Ezekiel 33:29. In such cases, the word is derived from the Hebrew word zera
The evolution of the seed was a crucial step for the rapid expansion of gymnosperm and angiosperm plants. The seed habit, together with a range of other characteristics such as enhanced sporophyte and reduced gametophyte, allowed these plant groups to rapidly dominate the terrestrial flora.
A seed is a fertilized ovule enclosed in a protective tissue called the endosperm. Most seeds contain one cotyledon in monocots, two in dicots, and three or more in gymnosperms. The cotyledon is the first leaves to emerge from the seedling, and it is pressed closely against the endosperm to absorb food for growth.
Most seeds are dispersed by birds, mammals, and other animals. They can also be carried by water or wind. Seeds are the source of many medicines including the quack cancer drug laetrile, tea tree oil, and castor oil. They are also the main source of vegetable oils, cereals, nuts and legumes, and important food additives such as gluten.
Seeds are an important part of the reproductive system of flowering plants. They contain the embryo of a new plant along with a reserve of food for its early development after germination. They are encased in a protective outer covering called a testa.
Seed dispersal is essential for the survival of plant species. If plant species grow too closely together they compete for light, water and nutrients in the soil. Seeds allow plants to move to different locations where they can get the resources they need without competing with other plants for these resources.
Seeds are well adapted for dispersal by animals, wind or water. Floating seeds can travel long distances and are especially useful for spreading plants that thrive in aquatic environments, such as mangrove trees. Seeds also have features to withstand harsh temperature and moisture conditions, such as a hard seed coat, cotyledons and endosperm. The seed also has an opening, known as the hilum and micropyle, that allows water to enter during germination.
Seeds contain all the things a new plant needs to begin growing. Inside each seed is an embryonic (baby) plant and a food supply. As a seed absorbs water, its embryo grows and its food supply breaks down to provide energy for the growing embryo. Then the embryonic root (radicle) pushes through the seed’s covering layers. Eventually, the cotyledons — the first leaves of the plant — form.
Scientists still don’t fully understand all the processes that take place during seed germination. However, they do know that the embryo in a seed swells up when it soaks up water and produces enzymes to help speed up its growth and germination.
Some seeds need the right temperature to germinate, and others need a certain amount of sunlight to grow and produce their own food. Gardeners and horticulturists try to break the physiological dormancy of many seeds by gradually exposing them to day and night temperatures, wind, moisture, air movement, and light.