abscission

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abscission The separation of a leaf, fruit, or other part from the body of a plant. It involves the formation of an abscission zone, at the base of the part, within which a layer of cells (abscission layer) breaks down. This process is suppressed so long as sufficient amounts of auxin, a plant growth substance, flow from the part through the abscission zone. However, if the auxin flow declines, for example due to injury or ageing, abscission is activated and the part becomes separated.

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