A seed is a part of a plant that can grow into a new plant. It includes an embryo, a supply of nutrients for the embryo, and a protective coat that keeps out wind and rain.
In gymnosperms (such as conifers), seeds form between the scales of a cone or in a berrylike cup. In angiosperms, such as flowers, seeds develop in sacs called ovaries. The ovaries then form a structure like a fleshy fruit or nut, which encloses the seed.
What is a seed?
A seed is a fertilized ovule containing an embryo or miniature undeveloped plant and food reserves enclosed within a protective seed coat. This is the characteristic reproductive organ of spermatophytes, or seed plants (gymnosperms and angiosperms).
Early seed plants evolved around 300 million years ago. They were similar to modern trees such as ginkgoes, which reproduced with pollen and seeds in cones.
They became dominant in forests during the Mesozoic Era, or Age of the Dinosaurs. Today, they are still the largest and most diverse group of plants.
Seeds are also an important food source for many animals. They can be eaten by herbivores such as insects, or by fruit-eating animals like bears and squirrels.
What are the parts of a seed?
In a flowering plant, there are three parts that work together to help a seed develop and grow into a new plant. They are the seed coat, endosperm and embryo.
The seed coat protects the internal parts of a seed, including its embryo, and stores food for the embryo. This part is usually hard, thickened or brownish and partially impermeable to water.
The embryo is the most important part of a seed, it contains all the cells needed to develop into a plant. It has a primary root that creates a long anchor root deep in the soil and cotyledons that provide nourishment during germination.
What are the functions of a seed?
Seeds are a central feature of spermatophytes, or seed plants. These are divided into gymnosperms, or “naked-seeded” plants like conifers and cycads; and angiosperms, flowering plants with seeds enclosed in ovaries.
Most seeds germinate only when conditions are perfect, usually under proper soil moisture and temperature. This is called dormancy, and it protects many species from suffering during periods of bad weather, transient herbivores or competition from other plants for light and nutrients (Penfield and King, 2009; Graeber et al., 2012).
Some seeds have specialized parts that entice animal dispersers to eat them; others have sticky hairs or barbs that attach to fur and feathers; and some have wings for wind dispersal. All of these are designed to ensure that a seed can reach the right place for growth and reproduction.
What are the uses of a seed?
Seeds are used for many different purposes, such as food, plant breeding, and landscaping. They are also used in medicine and for producing fibers, paper, and textile dyes.
Most seeds grow inside a fruit that encloses them and protects them from damage, such as sun or wind exposure. This type of protection is called a seed coat.
A seed is a miniature plant embryo and a store of food for the new plant to begin growing. This food supply, called endosperm or cotyledons, supports the sprouting seedling until it grows roots and leaves.
Seeds can be made by a number of plants, and most flowering plants produce them. In angiosperms, seeds are enclosed within a hard or fleshy fruit. In gymnosperms, seeds are not enclosed in a fruit and are referred to as naked.
