Seeds are the basic unit of plant life. They have the three components of germination, cotyledons, and endosperm. Each has its own specific function and must be taken into consideration when growing your own garden.
Endosperm
The endosperm of a seed is a collection of stored food. The endosperm of a dry seed is thin-walled and contains grains of protein. During germination, the endosperm is biochemically activated. It contains reducing sugars, proteins, and oils. As the embryo develops, the reducing sugars and proteins disappear, leaving starch. The cotyledons grow until they are about as long as the endosperm.
Several studies have been conducted to investigate the structure of the cell walls of the endosperm cap during germination. Some have used scanning electron microscopy (TEM) or cryo-scanning electron microscopy (cryo-SEM) to examine the effect of the germinated seed on its morphology.
In a study by Williamson and Duncan, porous cell walls were observed in raspberry fruit cells. They concluded that the enlarged cell wall was due to the activity of an enzyme, endo-b-mannanase. The same enzyme was found to be active in the endosperm cap of photodormant seeds.
Other researchers have described the occurrence of hydrolysis of tissues that oppose the radicle tip. These include oxididase and a class I b-1,3-glucanase.
Cotyledons
The cotyledon is a part of the seed plant that provides the plant embryo with nutrients. Cotyledons act as a shield between the developing embryo and the endosperm. They may also be photosynthetic.
The number of cotyledons in a seed can affect how it develops. For example, sunflowers have two cotyledons, while corn stems have one. In some plants, the cotyledons can persist for up to a week. They are also the first leaf of the seedling.
In plants with a single cotyledon, such as angiosperms, the cotyledon acts as a shield between the embryo and the endosperm. It is an important feature in classifying plants. Besides providing a plant with a photosynthesis source, the cotyledon can be used to absorb nutrients from the endosperm.
The cotyledon is found in angiosperms and monocots. In angiosperms, cotyledons are formed when the endosperm breaks through the soil. The cotyledon provides a place to grow until the endosperm is consumed. During the early stages of seed formation, the cotyledons are the main producers of photosynthetic material. The cotyledon can also provide the plant with an energy reserve for its development.
Germination
The germination of seed is an important event in the development of a new plant. The germination process is important because it enhances metabolic activities and transports soluble food from the storage tissue to the developing embryo.
Seeds of different plants have evolved to respond to certain environmental conditions. This includes temperature, light, and water availability. These environmental factors affect the germination of the seed.
Germination involves several changes until the seedling develops. For instance, a radicle emerges from the seed coat and penetrates the coleorhiza. This is followed by the sprouting of the shoot and the formation of the first leaves.
The germination of the seed depends on the availability of oxygen. A lack of oxygen can negatively impact the germination of the seed. A gas-resistant seed coat limits the exchange of oxygen.
In addition to oxygen, the germination of the seed requires adequate water. It is possible for the seed to develop at a lower temperature than it would under more favourable environmental conditions.
Storage
A seed bank is a storehouse of seeds that can be used for propagation. If seeds are stored properly they can last a long time. However, they must be kept dry and cold.
If you are storing seeds, make sure that the temperature is controlled. Seeds can be stored in a refrigerator for several years. The storage life is dependent on the type of seed and its moisture content. Using a hygrometer to keep track of the relative humidity will allow you to determine the amount of moisture in the seed.
To avoid fungal rots, insects, and fungi, store seeds in an airtight container. Label each seed pack to help you locate them easily.
To increase the storage life of your seeds, use desiccant. A silica packet from a new item works well, but rice or powdered milk can also work.
If you have very small seeds, they should be placed in self-seal plastic bags. These should be labeled with the crop name and date.
