What makes the grass green?
In the summer months, millions of boys take on the man sized job of mowing the lawn. They soon learn that the velvety grass grows only when it is green. If the mowing chore is skipped for a week or two, the grass turns brown and goes to seed. Its growing season is over and the lawn wall look like a patch of brown hay until spring coaxes it green again.
A blade of grass is made of plant cells, fitted tightly together like stacks of tiny boxes. If the grass is alive and healthy, its cells contain protoplasm and other juices. In order to grow, the grass must contain chlorophyll and this marvelous, mysterious substance is green.
The chlorophyll is stuffed into tiny bodies called chloroplasts and it may be blue green or yellow green. In most green plants, the chloroplasts are round or disc shaped and a powerful microscope shows them to be filled with lumpy granules. The average size of a chloroplast is five microns a micron is one thousandth part of a millimeter and a millimeter is one thousandth part of a meter, which is about one yard long.
Some plant cells contain only one chloroplast and others contain 50 or more. The tiny bodies float in the fluid protoplasm, often in a row or two around the cell walls. It takes countless numbers of them to make a plant look green and it is estimated that there may be 27 million of these tiny chloroplasts in a square inch of leaf surface.
For a long time we have known that green chlorophyll manufactures sugar, the basic food of plants. Once or twice, the experts thought they had discovered how this was done.
The process is called photosynthesis, which means putting together with light, for chlorophyll user the energy of sunlight to make sugar from gases in the air, water and perhaps other chemicals in the soil.
Many expert teams are working to discover just how the chlorophyll in grass and other green plants performs its wonderful recipe, Someday, the puzzle will be solved and our chemists may be able to manufacture sugar from air and water as the green grass does. But at the present time, the green chlorophyll of the plant world performs its magic in secret.
Chlorophyll is just about the most important substance in our world, for without it life as we know it would come to an end. It supplies the oxygen we breathe and without it plants could not brow. We eat salads and vegetables and the animals that give us meat and dairy products also eat plants. So chlorophyll starts the chain of events which supplies our food.