layer of tissue called the abscission layer develops at the base of each leaf stalk, and at this point the stalk breaks and the leaf is shed. The massive leaf drop that ensues during autumn has earned the season its alternate designation, fall.

Where is the abscission zone located?

In deciduous trees, an abscission zone, also called a separation zone, is formed at the base of the petiole. It is composed of a top layer that has cells with weak walls, and a bottom layer that expands in the autumn, breaking the weak walls of the cells in the top layer. This allows the leaf to be shed.

What is the abscission layer in plants?

The abscission layer, a barrier of thin-walled parenchyma cells, develops across the stem (or petiole) at the base of a leaf, flower, or fruit as it approaches the time of falling from a plant.