Dennis Anfinson, age 13, of Pierson, Iowa, for his question:

What makes fruit different colors?

The lush colors of fruit are related to the gorgeous colors of the fall landscape. Both are caused by chemicals which the plants manufacture during the course of the summer. The process, of course, begins when the plant makes simple sugar. This is done by photosynthesis, the magic recipe by which a plant makes sugar, using sunlight to rearrange the molecules of carbon dioxide in the air and water in the soil.

Photosynthesis is carried on by green chlorophyll, which is a clear liquid teeming with tiny bodies called ehloroplasts. A11 through the growing season, the pl4nt needs plenty of chlorophyll to produce the sugar which will be processed into countless different plant chemicals. It is present in the leaves, often in the stems and always in the young growing f rui t.

The plants, however, contain other chemicals of varying hues. But the plentiful green chlorophyll masks these colors, When the chlorophyll is no longer needed, its chemicals break up and disappear. Then the other chemicals show their colors. The fall trees are adorned with rainbow hues. The fall fruits glow with shiny purples, blush with yellows, reds and golds.

The chemicals which cause these colors fall into two groups. The group called the carotenes range from yellow to red. You can remember them because they are named for the foxy orange red of the carrot. Yes, the carotenes color many flowers and leaves, besides certain fruits. Actually, these plant chemicals are present in all green leaves all the time. During the green season, they are masked by chlorophyll.

Goldenrods, zinnias, primroses and sunflowers all get heir red and yellow colors from the presence of carotene chemicals in their petals.

Carotenes also give colors to tomatoes, oranges, lemons and grapefruit. Certain seeds, such as peas, clover and golden corn are also colored with carotene chemicals.

Almost all young fruits contain both chlorophyll and carotene chemicals. Some also contain chemicals called anthocyanins which may mask the green and red yellow chemicals of chlorophyll arid carotene. The anthocyanins range through reds, purples and blues. They color the plums and the purple grapes.

The chlorophylls and the carotenes are present in the leaves and young fruit throughout the summer. Most, though not all of the anthocyanins, however, are manufactured by the plants in the fall. In a few cases, these chemicals too are present and masked throughout the green season. They tinge the beech leaves and hide in the tender young leaves of the hazel and barberry,