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  MG Manual Reference
Ch. 1, pp. 15 - 16
[Plant Parts and Functions: stems | leaves | buds | roots | flowers | fruit | seeds]


A bud is an undeveloped shoot from which embryonic leaves or flower parts arise. The buds of trees and shrubs of the temperate zone typically develop a protective outer layer of small, leathery, bud scales. Annual plants and herbaceous perennials have naked buds in which the outer leaves are green and somewhat succulent.
Buds of many plants require exposure to a certain number of days below a critical temperature (rest) before they will resume growth in the spring. This time period varies for different plants. The flower buds of forsythia require a relatively short rest period and will grow at the first sign of warm weather. Many peach varieties require 700 to 1,000 hours of temperatures below 45°F (7°C) before they will resume growth. During rest, dormant buds can withstand very low temperatures, but after the rest period is satisfied, buds become more susceptible to weather conditions and can be damaged easily by cold temperatures or frost.
A leaf bud is composed of a short stem with embryonic leaves, with bud primordia in the axils and at the apex. Such buds develop into leafy shoots. Leaf buds are often less plump and more pointed than flower buds.
A flower bud is composed of a short stem with embryonic flower parts. In some cases the flower buds of plants which produce fruit crops of economic importance are called fruit buds. This terminology is objectionable because flowers have the potential for developing into fruit. This development may never occur because of adverse weather conditions, lack of pollination or other unfavorable circumstances. The structure is a flower bud and should be so designated since it may never set fruit.
Types of BudsTop
Buds are named for the location which they inhabit on the stem surface. Terminal buds are those which are located at the apex of a stem. Lateral buds are borne on the sides of the stem. Most lateral buds arise in the axis of a leaf and are called axillary buds. In some instances more than one bud is formed. Adventitious buds are those which arise at sites other than in the terminal or axillary position. Adventitious buds may develop from the internode of the stem; at the edge of a leaf blade; from callus tissue at the cut end of a stem or root; or laterally from the roots of a plant.
Buds as FoodTop
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 of Brussels sprouts become the edible part of this plant. In the case of globe artichoke, the fleshy basal portion of the bracts of the flower bud are eaten along with the solid stem portion of the bud. Broccoli is the most important horticultural plant in which edible flower buds are consumed. In this case, portions of the stem as well as small leaves associated with the flower buds are eaten.

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