Alien Ft. Best, age 8, of Houston, tex., for his question:
Do plants breathe?
We need oxygen day and night and so do the countless animals. Plants also need oxygen day and night. All this oxygen gas is poured into the air by the green plant world. The leafy trees and the growing corn, the grass and other greenery pour out enough oxygen for themselves and all the other plants, enough for all the animals and all the people in the world.
We take oxygen from the air and send back carbon dioxide. This, of course, is breathing. Plants also take oxygen from the air and send back carbon dioxide but the experts do not call this breathing. Instead, they use i;he big word respiration. We carry on breathing day and night, and plants carry on respiration day and night.
A plant has no nose to take in oxygen and send out carbon dioxide. The air seeps in and out through tiny pores, and the experts have a fine sounding name for them. They are called stomata. The stomata are crowded all over leaves and stems, but these miniature doorways are too small for our eyes to see. Air seeps in and out through the stomata.
The plant is made from stacks of tiny boxes called cells. The air from outdoors seeps in and among these boxy cells. The living cells take oxygen from the air and use it to do their work. As they work, they make carbon dioxide which is not needed.
This waste gas seeps outside through the stomata.
A green plant uses sunlight to make sugar from water and carbon dioxide. Sugar is its basic food. But wheat needs protein to make its seeds, a mealy potato must be made of starch and a rose needs fats to make its oily perfume. The plant uses oxygen to change its sugar into these and many other materials. This job is the most important part of respiration.
The sugar needs oxygen to change itself. The oxygen is a chemical fuel which changes the sugar back again into carbon dioxide and water. We have a big word for this job. Because oxygen is used as a fuel, we call this change oxidation. And oxidation gives the plant the energy it needs to build different things of different materials.
Plants use sunlight to make sugar and more sugar. This magic recipe calls for carbon dioxide. This, of course, is the waste gas We breathe out and the plants send out from their respiration. In the sugar making recipe, plants need carbon dioxide. And oxygen is the waste gas. During the day, green plants pour out oxygen and more oxygen. They need some of this oxygen for their respiration. The rest is there for us to breathe.