ISA Certification

Abscission Zone

Area at the base of a petiole, small branch, or flower where cellular breakdown leads to leaf, flower, or fruit drop

Absorbing Roots

Find roots with functional root hairs that are responsible for the uptake of water and minerals

Adventitious Bud

Bud arising peripherally from a place other than a leaf axil or shoot tip, usually as a result of hormonal triggers

Aerial Roots

Above ground roots. Usually adventitious in nature and sometimes having unique adaptive functions

Angiosperms

Plant with seeds, born in an ovary. Consists of two large groups: monocotyledons (grasses, palms and related plants) and dicotyledons (mostly woody trees, shrubs, herbaceous plants and related plants).

Anthocyanin

Red or purple pigment responsible for those colors and some parts of plants

Apical Bud

Bud at the tip of a twig or shoot

Apical Dominance

Condition in which the terminal bud inhibits the growth and development of the lateral buds on the same stem formed during the same season

Apical Meristem

Growing point in buds and at the tips of shoots and roots

Auxins

Plant hormones that promote or regulate the growth and development of plants. Produced at sites where cells are dividing, primarily in the shoot tips. Auxin-like compounds may be synthetically produced.

Axial Transport

Movement of water, minerals, or photosynthates longitudinally within a tree

Axillary Bud

Bud in the axil of a leaf. Lateral bud.

Barrier Zone

Chemical and anatomical barrier formed by the cambium in response to wounding. Inhibits the spread of decay into xylem tissue formed after the time of wounding. Wall four in the CODIT model.

Branch Bark Ridge

Raised strip of bark at the top of a branch union, where the growth and expansion of the trunk or parent stem and adjoining branch push the bark into a ridge

Branch Collar

Swollen area where a branch joins the trunk or another branch that is created by the overlapping vascular tissues from both the branch and the trunk

Branch Union

Point where a branch originates from the trunk or another branch

Bud

Undeveloped flower or shoot containing a meristematic growing point. Small lateral or terminal protuberance on the stem of a plant that may develop into a flower or shoot.

Buttress Roots

Roots at the trunk base that help support the tree and equalize mechanical stress