The Onios - Particularities - Medicinal plant
Onion
The onion (Allium cepa l.) is a bulbous herbaceous plant of the family Liliaceae.
Particularities
Native to central Asia, currently the onion is one of the essential ingredients of Mediterranean cuisine.
It has a single large bulb, of ovoid shape. Its development is biennial and reaches 1 m in length. Its leaves are semi-cilíndriques and are born from an underground bulb, equipped with surface roots. Its stem is erect and usually originates in the second year of maturation of the plant. At its end has an umbel of white flowers or pink. Other names by which it is known in Catalan are white onion, onion of Egypt or onion porringer.
Crying to chop the onion
In being cut off, the bulb gives off a volatile oil that produces sulfurat tearing by irritation of the conjunctiva.
When you cut or eats the onion bulb some of their cells are broken, allowing enzymes called sulfòxids that al·liinases and generate sulfenic acid degraded when amino acids. A sulfenic acid acid specific format called propenesulfèic-1, when you cut onions, can you re-arrange for a second enzyme which is called LFS (lachrymatory factor:) giving rust is sin-propanetial, which is a volatile gas known as tear factor of the onion or LF. The LF gas will spread through the air and eventually reaches the eye, where it activates neurons, creating the feeling piquant. The lacrimal glands produce tears to dilute and eliminate the irritating flow. < ref-name = "Sciam" > Scott, Thomas. "What is the chemical process that causes my eyes to tear when I peel an onion?". Ask the Experts: Chemistry. Scientific American. Chemicals which produce effects such as these in the ulles called tear agents.
Supplying enough water in this reaction as he peeled the onions prevents the gas reaches your eyes. The irritation of the eye can be avoided if you cut the onions under running water or doing it with the onion in a bowl with water. another way to reduce eye irritation is for cooling or a base not to cut the roots of onions (or do it at the end), because the root of the onion has a high concentration of enzymes. using a sharp knife to cut or grind the onions limits the damage to their cells and the release of enzymes that give the answer irritating. Cooling or freezing onions prevents the activation of enzymes by limiting in this way the gas generated.
You can also prevent the irritation of eyes having a fan that grows the gas of the eyes or taking an eye protection. also contact lenses limit irritation.
The amount of sulfènics acids and LF released and the irritating effect differ between the species of the genus Allium. In 2008 in New Zealand was to create a strain of onions lacrimògenes not using biotechnology to silence genes.
As medicinal plant
Used primarily in the food, so the secondary onion also has a reputation as a medicinal plant, and has been used in the treatment of asthma, diabetes, hypertension, etc.
Cultivation of onions
It has a strong resistance to drought although it may miss the water in the critical period for the thickening of the bulb. When it is done in dry regime, in order to take advantage of the months usually less dry, used the early varieties that already are harvested in may or in June, before the strong heat of the summer. If the onions go through excessive hardship of water are very coents and with little bulb.
Currently in extensive agriculture is grown by direct seeding but traditionally made a seedling that will trasplantava after about two months in late fall or late winter and early spring.
A physiological problem is very common that some onions were "trompin", that is to say, that grow the thalamus floral, when they pass the winter cold. Then, if you don't cut them soon, no longer make the bulb.
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