Jane Devane, Age 10, of Georgetown, Ind., for her question:
How does a rose get its scent?
A pint of rich perfume costs hundreds of dollars, yet most of its ingredients are made from air, water and common chemicals in the soil. Scientists can imitate the scents of some flowers, but plants still make the best perfumes with their awn secret recipes. What's more, it is no easy job to capture and preserve these sweet scents, which is why good perfume is so costly.
The perfume of a rose is manufactured by a secret recipe right inside the rose tree. Like all green plants, the rose tree needs only air and sunshine, water and chemicals from the soil to make a living. It uses no more than these common ingredients to grow its woody stems and its green leaves, its spiky thorns and satin smooth flowers. The same basic ingredients are used to color and perfume the glamorous roses.
Like every green plant, the rose tree does its basic work during the daylight hours. It carries on a complex process called photosynthesis, a fine sounding word which means putting together with light. Green chlorophyll in the leaves and stems is needed to carry on this sunshine recipe. The chlorophyll uses sunlight to change carbon dioxide from the air and sap from the soil into a simple kind of sugar.
This sugar is the plant's basic food. The water in the soil dissolves chemicals which are added to the plant's sap. Traces of these chemicals are used by the growing rose tree, but the basic building material is sugar created by photosynthesis. These chemicals are converted into woody cells to make stems and thorns, finer cells for leaves and petals, pigments to color the roses and a complex chemical to perfume them with fragrance.
Rose perfume is an oily chemical, so strong that a drop is enough to scent 100 flowers. It is stored in tiny pockets among the fine cells which make the satiny petals. This rich oil tends to evaporate in the air, and when this happens, its rosy fragrance spreads far and wide. One way to release the perfume is to crush the rosy petals. This breaks open the perfume sacs and the oil evaporates, releasing its scent in the air.
A fading rose has a sickly odor, for its perfume is made to last but a short while. Perfume makers must preserve the fragrance of fresh roses. The job requires patient work and skillful know how as well as expensive ingredients, such as musk or ambergris. This explains why bottled perfume is so costly, though it is made from such common items as air and water.