. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. 88 BOTANY. Young embryo of corn, showing root hairs () and growing stem (-P.)' Fibrovascular Bundles. — Collections of such tubes and sup- porting woody cells together make up what is known as fibro- vascular bundles. Structure of a Root Hair. — The cells of the cortex are almost uniform in character. The outmost layer, however, differs from the rest of the cortex. This layer is called the epidermis. It is the prolongations of the cells of the epidermis that form the structures we have
. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. 88 BOTANY. Young embryo of corn, showing root hairs () and growing stem (-P.)' Fibrovascular Bundles. — Collections of such tubes and sup- porting woody cells together make up what is known as fibro- vascular bundles. Structure of a Root Hair. — The cells of the cortex are almost uniform in character. The outmost layer, however, differs from the rest of the cortex. This layer is called the epidermis. It is the prolongations of the cells of the epidermis that form the structures we have already seen and know as root hairs. Let us now take out one of the small radish seedlings from the pocket garden, mount it in water, and examine it under the low power of the microscope. A single root hair will be found to be a long round structure, almost colorless in appearance. The wall, which is very flexible and thin, is made up of cellulose, a substance somewhat like wood in chemical composition, through which fluids may easily pass. If we had a very high power of the microscope focused upon this cellulose wall, we should be able to find under it another structure, far more delicate than the cell wall. This is called the cell membrane. Clinging close to the cell membrane is the protoplasm of the cell, which in the root hair is found close to the membrane. The interior of the root hair is more or less filled with a fluid called cell sap. Forming a part of the living protoplasm of the root hair, sometimes in the hairlike prolongation and sometimes in that part of the cell which forms the epidermis, is found a nucleus. The protoplasm, nucleus, and cell membrane are alive; all the rest of the root hair is dead material, formed by the activity of the living substance of the cell. The root hair is a living plant cell with a wall. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appea
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