Douglas Blake, age 10, of 'Montgomery, Ala., for his question:

What is the green color in plants?

If you have a keen eye, you can detect a multitude of green tones in the plant world. Furry pine boughs wear a deep dark green, some of the lacy ferns wear pale, watery green. Fragrant lavender bushes are gray green, and many floating seaweeds are blue green. Every healthy plant favors its own particular preen. And all the greens of the plant world are created by delicate biochemicals called chlorophylls.

When we look at a green leaf, we are seeing chlorophyll shining through the thin cell walls. When we squeeze this coloring material out, sae get a rich green liquid. Host. of it is water and we need a powerful microscope to see what adds the color to liquid chlorophyll. It is packaged in millions of tiny ball shaped bodies called chloroplasts. A billion or more of these chloroplasts crowd near the surface of a leaf.

A more powerful microscope reveals just how the chlorophyll is stuffed into the little round packages. When we see that the actual chlorophyll color comes in tiny grains. And nature is neat, even in this miniature world of microscopic particles. Inside the chloroplast, the grains of chlorophyll are stacked like orderly piles of little round dimes.

A still stronger microscope reveals that each grain of chlorophyll is stuffed with still smaller bodies. These are called quantasomes. The microscope can take us no farther. But chemical researchers assure us that each quantasome contains about 200 molecules of chlorophyll, the pigment that paints the plant world green.

Molecules, of course, are chemical packages of assorted atoms. The basic ingredients used to build the green pigment are atoms of carbon and hydrogen, oxygen, sodium and magnesium. Chlorophyll molecules are very complex, and several slightly different recipes are used to create the varied greens of the plant world.

Just a few types of chlorophyll create an endless array of blended greens and yellows. The most common is a grassy green pigment called chlorophyll 11 A. Each of its molecules is a complex package of 55 carbon atoms and 72 hydrogen atoms, five atoms of oxygen and four of sodium, plus a single atom of magnesium.

These are the molecular ingredients packed into tiny quantasomes, which are packed into & rains, which are stacked neatly into chloroplasts. The chloroplasts float in the watery cytoplasm that fills the cells of every green plant. Billions of these tiny bodies are needed to add visible color to a leaf.

Chemically, chlorophyll is a greenish chemical, but the color is merely window dress¬ing. Chlorophyll is the miraculous biochemical that makes all life on this planet possible. The plant world creates it for the purpose of photosynthesis. This vital process uses the energy of sunlight to manufacture basic plant food from air and water. Oxygen is a by product of this process, and chlorophyll produces all the oxygen needed to sustain every person, plant and animal on the earth.