February 10, 2010

Fertilization of Crop

Fertilization of Crop
The pistil is a complex part of a flower. It is complete in itself as a reproductive organ, from the stigma box to the ovary it is viable enough for reproduction even without the petals or corolla.

It is composed of various elements called the carpels which are untied to enclose a cavity or several cavities housing the rudimentary seeds or ovules.

The enlarged basal part where the ovules are nourished is called the ovary.

The upper portion of the pistil is the stigma box containing the viscous secretion on which the pollen gets deposited.

As the pollen gets deposited this takes in food and water and the tube develops rapidly downward into the ovary, where fertilization takes place as the pollen punctures the ovule.

As the ovule or egg cell unites with the pollen a zygote is formed, which is actually the beginning of the new plant.

The zygotes grows into an embryo and the tissue around it undergo various changes forming an outer coat and an inner tissue filled with food called the endosperm.

The ovule, consisting of the embryo, endosperm and coat becomes the seed.

In full development an embryo can lie dormant for many weeks to even years as it is protected by its seed coat and with its own store of food and upon germination can sent out immediately leaves and roots which are ready to draw nourishment from its immediate environment.

Seeds vary in size from a minute macroscopic size of the orchids to the giant size of the coconut seed.

Seed vary in color, size shape and number. Some are edible others are poisonous. The presents of food in a seed is the reason why it is important to man and animals.

Man depends on these various seeds for food and nutrition as animals also do. The starches from cereal, oils, from huts, sugar from corn and protein from legumes, make seeds very important.
Fertilization of Crop

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