Seeds are an important part of many plants. They store food, travel away from their parent plant and grow into a new plant.
In angiosperms, the seeds consist of an embryo and endosperm tissue. Embryos are formed during fertilization, and endosperm is produced later.
They store food
During the germination process, seeds store food for the embryo within their seed. The form of this stored food varies depending on the type of plant, but is typically in the endosperm and/or cotyledons.
The embryo, which is surrounded by a seed coat, will use this stored food to start a new plant. Generally, this stored food is in the form of fats and proteins.
In angiosperms, this stored food is found within the endosperm. In gymnosperms, such as conifers, this stored food is in the perisperm.
One of the biggest enemies of seeds is sunlight, so it’s a good idea to keep them in dark, opaque containers when possible. Another enemy is moisture, so try to find a storage container that doesn’t allow the seeds to absorb water from the air.
They travel away from the parent plant
For a seed to germinate and grow into a new plant, it needs water, space and sunlight. If it drops straight to the ground beneath an adult plant, it might face strong competition for these resources.
To help their seeds survive, many plants have developed ways to disperse them away from the parent plant. The most common methods are wind, water, animals and fire.
The wind can carry seeds a long distance, depending on their size or weight. For example, the tufts of hairs on the seeds of dandelions and milkweed called pappi catch the wind and propel them far from the mother plant.
Some seeds are light enough to float in water, like coconut or mangrove seeds.
Animals can eat the seeds, breaking down the protective covering and excreting them far from the parent plant. This is called allochory, and is a type of dispersal that relies on external forces, unlike autochory, which happens when the seeds are moved by their own means.
They grow into a new plant
A seed is the mature ovule of a flowering plant (angiosperms), or the reproductive organ of spermatophytes (gymnosperms). It contains a miniature undeveloped plant (the embryo) and food reserves (endosperm) that are enclosed in a protective coat called a testa.
When the embryo inside a seed germinates, it begins to soak up water from the environment. This helps it start to use the stored energy within its cells.
The embryo also needs oxygen and the right temperature for germination to take place. If the seed does not have these three conditions, it will stay dormant and unable to germinate.
Embryonic leaves, known as cotyledons, begin to form when seeds germinate. They look different for each plant family. For example, tomato, pepper and eggplant seedlings have a pair of long, narrow leaves; radishes and broccoli have stubby, heart-shaped cotyledons. The cotyledons provide a support system for the developing true leaves that grow above them.
They are a source of food
Seeds are the food sources of many plants. They are a major source of calories, protein, and minerals. They are the main components of plant foods such as grains, legumes, nuts and spices.
Most seeds have a protective shell, or seed coat, that helps them keep their embryo, a tiny plant, and the endosperm, small leaves that provide the embryo with food, from drying out. These coats vary in thickness, from soft as in beans to hard as in locust and coconut seeds.
Within a seed, there is usually a store of nutrients that the embryo needs to grow into a new plant. Depending on the type of plant, this is in the form of a tissue called the endosperm or in some cases, aleurone grains.
Seeds are a great source of fiber that can help with digestion and stabilize blood sugar levels to prevent sudden spikes and crashes. They are also a good source of omega-3 fats, which can help lower inflammation and reduce the risk of certain diseases, including heart disease and cancer.