Buds

       A bud is an undeveloped shoot from which leaves or flower parts grow. The buds of temperate-zone trees and shrubs typically develop a protective outer layer of small, leathery scales. Annual plants and herbaceous perennials have naked buds with green, somewhat succulent, outer leaves.
Buds of many plants require exposure to a certain number of days below a critical temperature before resuming growth in the spring. This period, often referred to as rest, varies for different plants. Forsythia, for example, requires a relatively short rest period and grows at the first sign of warm weather. Many peach varieties, on the other hand, require 700 to 1,000 hours of temperatures below 45°F. During rest, dormant buds can withstand very low temperatures, but after the rest period is satisfied, they are more susceptible to damage by cold temperatures or frost.
A leaf bud is composed of a short stem with embryonic leaves. Leaf buds often are less plump and more pointed than flower buds (Figure 10a). A flower bud is composed of a short stem with embryonic flower parts. In the case of fruit crops, flower buds sometimes are called fruit buds. This terminology is inaccurate, however; although flowers have the potential to develop into fruits, they may not do so because of adverse weather conditions, lack of pollination, or other unfavorable circumstances.

Location

Buds are named for their location on the stem (Figure 10b). Terminal buds are located at the apex (tip) of a stem. Lateral (axillary) buds are located on the sides of a stem and usually arise where a leaf meets a stem (an axil). In some instances, an axil contains more than one bud.
Adventitious buds arise at sites other than the terminal or axillary position. They may develop from roots, a stem internode, the edge of a leaf blade, or callus tissue at the cut end of a stem or root. Adventitious buds allow stem, leaf, and root cuttings to develop into entirely new plants.

Buds as food

Enlarged buds or parts of buds form the edible portion of some horticultural crops. Cabbage and head lettuce are examples of unusually large terminal buds. Succulent axillary buds are the edible part of Brussels sprouts. In the case of globe artichoke, the fleshy basal portion of the flower bud's bracts is eaten, along with its solid stem. Broccoli is the most important horticultural plant with edible flower buds. In this case, portions of the stem, as well as small leaves associated with the flower buds, are eaten.