Once pollen reaches the ovary inside the flower, the ovary becomes a fruit. The eggs inside the ovary become seeds inside this fruit. Sowing a seed starts the process all over again: the new plant, although similar to the parent plant, is not identical. About 80 to 85 percent of our caloric needs are met through seeds, either directly as food or indirectly through use as food.
Seeds are the result of plant reproduction. During the flowering period, male and female tissues interact with each other in various ways. When pollen falls on the stigma of the flower, it germinates and forms a pollen tube, which then grows rapidly towards the plant's ovary. Once it finds an egg, the pollen tube bursts to release sperm, which fertilize the egg and start seed formation.
Seeds are the product of the mature egg, after the embryonic sac is fertilized by pollen sperm, forming a zygote. The embryo within a seed develops from the zygote and grows inside the parent plant to a certain size before growth stops. The seed coat arises from the egg integuments. Plant life begins with seeds, unless the plant reproduces by spores or vegetatively.
Where do seeds come from? They are the by-product of a flower or flower-like structure. Sometimes seeds are enclosed in fruits, but not always. Seeds are the primary method of propagation in most plant families. The seed life cycle begins with the flower and ends with a seedling, but many intermediate steps vary from plant to plant.
The seed of a sunflower is contained in its large flower, familiar to most of us because it is also a popular snack food. The seeds are also consumed by animals (seed predation), and are also fed to livestock or provided as canary seed. Plants that produce smaller seeds can generate many more seeds per flower, while plants with larger seeds invest more resources in those seeds and usually produce fewer seeds. Other appendages of the seed include the raphe (a crest), wings, caruncles (a soft, spongy outgrowth of the outer integument in the vicinity of the micropile), spines, or tubers.
Sometimes the fruits are harvested while the seeds are still immature and the seed cover is not fully developed and sown immediately before the seed cover becomes impermeable.
walnuts are
the hard-shelled fruit of a single seed of some plants with an indehiscent seed, such as an acorn or hazelnut. In endosperm seeds, there are two distinct regions within the seed cover, an upper and larger endosperm and a smaller lower embryo. Microorganisms are usually effective in breaking down hard seed covers and are sometimes used by people as a treatment; seeds are stored in a warm, humid sandy environment for several months under non-sterile conditions.For seeds planted in gardens, it is best to use running water; if they are immersed in a container, it is enough to soak them for 12 to 24 hours. Cecilia and her co-authors found that even though gymnosperms have a comparatively simple egg and seed structure relative to angiosperms, they have more copies of the genes that control egg and seed development. Inside the seed, there is usually a supply of nutrients for the seedling that will grow from the embryo. Small seeds mature faster and can be dispersed earlier, so in autumn all flowering plants tend to have small seeds.
Over a 20-year period, for example, forests composed of loblolly pine and short-leaf pine produced 0 to nearly 5.5 million healthy pine seeds per hectare. The description in 2004 of the protoseed of Runcaria heinzelinii in the Givetian of Belgium is an indication of the ancient origin of plants with seeds. Angiosperm seeds are produced in a hard or fleshy structure called fruit that encloses the seeds to protect them and ensure healthy growth. .
