Abscission (from ab- away from, and scission cutting or severing) is the shedding of a body part. It most commonly refers to the process by which a plant intentionally drops one or more of its parts, such as a leaf, fruit, flower or seed, though the term is also used to describe the shedding of a claw by an animal.

A plant will abscise a part either to discard a member that is no longer necessary, such as a leaf during autumn, or a flower following fertilisation, or for the purposes of reproduction. If a leaf is damaged a plant may also abscise it to conserve water or photosynthetic efficiency, depending on the 'costs' to the plant as a whole.

The gaseous plant hormones ethylene can stimulate abscission. Abscisic acid and auxins may also be variously involved in the process.

plant anatomy | plant morphology

Abszission | Abcisão