acclimate: gradually expose young plants to harsher environmental condition

aerial: above ground

agar:Audio icon a thick gel used to support plants in tissue culture

air layering: method of propagation that induces new roots to form on a mature stem without burying the stem in the soil, while the stem is still attached to the mother plant

annual: a plant that completes its entire growth cycle from seed to seed in one growing season

anther:Audio icon a plant structure that produces pollen that contains the male sperm of the plant

apex: the tip of the shoot or root (adjective apical)

apical dominance: the inhibition of growth of side buds by the shoot tip

asexual propagation: making new plants by using a vegetative organ of the plant such as a leaf, stem, or root

autoclave: an apparatus used to sterilize tools by creating high temperatures through pressure

auxin:Audio icon a plant hormone that stimulates elongation of shoots and roots and is used in plant propagation to stimulate root growth on stem and leaf cuttings