Pollen grainEach pollen grain contains a bit of male plant DNA. Pollen has a tremendous importance for life on Earth, because without it, there would be no plants or fruit. The pollen grains are usually yellow, but they can also be white, brown red or purple. It can be found in the anther sac of the stamen or in the male cone of a conifer. Pollen grain are microscopic to human eyes and measured in microns. There are thousands of grains in a pinch of pollen. The lifespan of pollen is less than two hours.
The pollen grain is made of three different parts. The central part is called the cytoplasmic part and it is source of fertilization nuclei. The intine is the inner layer, made of cellulose. The exine is the outer, durable layer, very resistant to disintegration.
Inside the anther, pollen cells divide through meiosis to form pollen grains. The nuclei of these grains contain half of the chromosomes characteristic to the parent plant. Each pollen grain has three nuclei: two sperm nuclei and one tube nucleus.
There are two types of pollination: cross-pollination and self-pollination. The cross-pollination is the process through which the pollen grains are transported from flower to flower by honeybees, insects, animals or wind, while the self-pollination is the process through which the pollen from the stamen of a plant is deposited on the pistil of the same plant. This is possible because certain plants have the anthers taller than the stigma. When the pollen arrives on the pistil a seed is produced. Seeds develop and turn into fruit.
Pollen grains that are transported by wind are responsible for the allergic reaction known as hay-fever, known by specialists as allergic rhinitis. People suffering from this seasonal allergy, sneeze, suffer from nasal congestion, tearing and itching eyes. When allergic people enter into contact with pollen, histamine is released from the tissues, a process which irritates the small blood vessels and mucus-secreting glands. The symptoms may be aggravated by emotional factors. The symptoms are reduced with the help of antihistamine drugs and inhaled corticosteroids.
Pollen grains are used in treating various diseases but pollen is also considered a food supplement. A type of pollen grain, called saffron is used in the Indian cuisine to make the famous spice: curry. Saffron is collected from the crocus flower. The pollen is taken from the laden stigmas and dried. Both the pollen grains and the stigmas are used to give flavor to the delicious dishes of the Indian cuisine.
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