22. Stem-growth

After the seed is established by starting rootlets the upward-growing shoot, or plumule, starts growth and soon forms perfect leaves. The root-growth, after the first extension of the hypocotyl, is by cell-growth at the tips something like the extension of an icicle except that the ice lengthens by addition from the outside and the root by the cell-growth within. The stem makes each year's growth by elongation usually at one time in the spring, something like the stories of a building. Each story of growth when young is shown by a slight enlargement, or by the leaf-scars as shown in Fig. 4. At the point between the one- and two-year-old wood, called the node, most starch is stored at the base of the buds. Hence in making cuttings Union of new of the new wood of the grape and many and older trees and shrubs the node is included, as wood (After Goff ) roots more readily start from this point. The part between the buds, known as the internode, after completion of its elongation, remains stationary. It increases in diameter, but never in length.

Stem growth

The stem or branches below the one-year-old growth never increase in length. The space between the nodes on a grape-vine or tree depends on the rapidity of growth. In nursery trees the thriftiness of growth can be determined by the purchaser by observing the length of the internodes. With evergreens, small fruits, and in other cases, it is often a gain to secure more compact growth by pinching the points during the season of active growth. Pinching stops the development of the succeeding node and causes the development and growth of buds farther back on the plant.