tailieunhanh - THE PLANTHOW A PLANT FEEDS FROM THE AIR

If you partly burn a match you will see that it becomes black. This black substance into which the match changes is called carbon. Examine a fresh stick of charcoal, which is, as you no doubt know, burnt wood. You see in the charcoal every fiber that you saw in the wood itself. This means that every part of the plant contains carbon. How important, then, is this substance to the plant! You will be surprised to know that the total amount of carbon in plants comes from the air. All the carbon that a plant gets is taken. | THE PLANT HOW A PLANT FEEDS FROM THE AIR If you partly burn a match you will see that it becomes black. This black substance into which the match changes is called carbon. Examine a fresh stick of charcoal which is as you no doubt know burnt wood. You see in the charcoal every fiber that you saw in the wood itself. This means that every part of the plant contains carbon. How important then is this substance to the plant You will be surprised to know that the total amount of carbon in plants comes from the air. All the carbon that a plant gets is taken in by the leaves of the plant not a particle is gathered by the roots. A large tree weighing perhaps 11 000 pounds requires in its growth carbon from 16 000 000 cubic yards of air. Perhaps after these statements you may think there is danger that the carbon of the air may sometime become exhausted. The air of the whole world contains about 1 760 000 000 000 pounds of carbon. Moreover this is continually being added to by our fires and by the breath of animals. When wood or coal is used for fuel the carbon of the burning substance is returned to the air in the form of gas. Some large factories burn great quantities of coal and thus turn much carbon back to the air. A single factory in Germany Pg 40 is estimated to give back to the air daily about 5 280 000 pounds of carbon. You see then that carbon is constantly being put back into the air to replace that which is used by growing plants. The carbon of the air can be used by none but green plants and by them only in the sunlight. We may compare the green coloring matter of the leaf to a machine and the sunlight to the power or energy which keeps the machine in motion. By means then of sunlight and the green coloring matter of the leaves the plant secures carbon. The carbon passes into the plant and is there made into two foods very necessary to the plant namely starch and sugar. Sometimes the plant uses the starch and sugar immediately. At other times it stores both .