The first root, as seen under children’s microscopes, formed by the young seedling is called the primary root. Later, with the use of children’s microscope, secondary roots branch from the primary root, and a root system is formed. If the branching results in a system of numerous slender roots, with no single root predominating, as in grass or clover, the plant is said to have a fibrous root system. If, however, the primary root remains dominant, with smaller secondary roots branching from it, the arrangement is called a taproot system. When viewed under children’s microscopes, dandelions, beets, and carrots, among others, are plants with taproots. As these examples suggest, taproots are fre¬quently specialized as storage organs for the products of photosynthe¬sis. Storage is a function of all roots, but particularly of taproots, when viewed under a microscope. Obviously, procurement of water and minerals and storage of high¬ energy organic compounds are not the only functions of roots; they also serve to anchor the plant to the substrate. (more…)

The raw materials most obviously needed by higher photosynthetic organisms are carbon dioxide and water. These two compounds, which can be visualized using a microscope such as children’s microscopes, sup¬ply the carbon, oxygen, and hydrogen that are the predominant elements in organic molecules. Carbon dioxide, one of the constituent gases of the earth’s atmosphere, is obtained directly from the air by the leaves of terrestrial plants; submerged aquatic plants absorb the dissolved gas from the surrounding water. Terrestrial plants obtain the other raw material, water, from the substrate in which they grow; most higher plants absorb water from the soil by roots. Water absorption of a plant from the roots can best be seen using children’s microscopes.

A very high percentage of the total dry body weight of a large tree is carbohydrate, and much of the rest of it was synthesized from car¬bohydrate. This fact, which was discovered with the use of a microscope, has some rather startling implications. Glucose, which may be taken as the central carbohydrate in protoplasm, contains six atoms of carbon, twelve of hydrogen, and six of oxygen. Now, the combined weight of the six atoms of carbon and six atoms of oxygen is about 93 percent of the total weight of a glucose molecule. Since all the carbon and oxygen incorporated into glucose by photosynthesis comes from carbon dioxide, which in turn comes from the air, it follows that about 93 percent of the weight of a large, immensely heavy tree comes initially from the air. The hydro¬gen in glucose comes from water, as seen under a microscope, and hydrogen constitutes roughly 7 percent of the weight of glucose; hence about 7 percent of the dry weight of the tree comes initially from water. It is the modern elu¬cidation of the process of photosynthesis that has established the amazing fact that most of the mass of a plant’s body comes from air, not from the solid earth in which it grows. (more…)