Assimilation The conversion of food into cell walls and cell contents. Asexual (or vegetative) propagation Production of a new plant by using a part of a parent plant, as opposed to sexual union reproduction of a plant by any means other than seed. Arthropods Invertebrate organisms of the animal kingdom that include insects, spiders, and Crustacea organisms characterized by an external skeleton and legs with movable segments or joints. Arms generaly bear the spurs and canes retained for fruit production. Arm (grape) The permanent divisions of the vine arising from the trunk in the case of cordon pruned vines. Arbor A shelter of vines or branches or of latticework covered with climbing shrubs or vines. Apomictic seed A seed developed from an unfertilized egg. Apical meristem The tissues at the tip of roots and shoots where cells divide, giving rise to new growth.

Apical dominance The influence of a terminal bud (apical bud) in suppressing the growth of lateral buds. Apical Located at or pertaining to the apex or tip. Anther The upper portion of the stamen that produces pollen grains. Annual A plant in which the entire life cycle is normally completed in a single growing season. Angiosperms Flowering plants that produce their seeds within a fruit (ovary) the most advanced class of plants. Anaerobic Occurring in the absence of oxygen or not requiring oxygen. Alternate bud and leaves The arrangement of buds or leaves singly at a node, usually on either side of the stem. Alternate bearing The bearing of heavier and then lighter crops of fruits in successive years. Air layering A propagation technique in which plant parts are rooted while they remain attached to the parent plant.

Agronomy The science of the production of crops grown on large acreages, such as grains and forages. Aggregates (soil) Clusters of soil particles variable in shape, size, and degree of association, such as granules, clods, or prisms, that give a soil its structure. Aerobic Occurring only in the presence of oxygen, or requiring oxygen. Aeration (soil) The process in which air in the spaces around soil particles is renewed. Adventitious Plant structures or organs, such as buds, shoots, or roots, produced in an abnormal position or that arise from other plant tissues. Glossary N - Z A Abscission The dropping off of a leaf, fruit, or flower.

Pine young staminate cone xylem phlo