Root Hairs

Figure 33-2 shows a longitudinal section of the growing tip of a root. Meristematic activity, which increases the length of the root, occurs only at the tip. When the cells here divide, they produce the new root cells and root cap cells. The root cap cells are sloughed off as the root grows through the soil. The epidermal cells produce root hairs a short distance above the tip. Root hairs are part of epidermal cells.

In figure 33-3, note the location of the nucleus. This seems to indicate the nucleus is positioned at a point of greatest activity. The only portion of a root able to take in water is the root hair; and the total surface area of root hairs available to perform this function is much greater than the total surface area of the leaves. Because root hairs are short lived (living perhaps a day), root hair production must continue in order for the plant to be maintained. It is estimated that one hundred million root hairs are produced each day in a rye grass plant

Figure 33-2 Longitudinal section of a root tip.

Figure 33-3 Root hairs pushing through soil. Root hairs are a part of epidermal cells.