Deciduous plants shed their leaves during summer or in autumn. This process of shedding of leaves is called abscission. Apart from physiological changes what anatomical mechanism is involved in the abscission of leaves?
i. Structural: In deciduous trees, an abscission zone also known as separation zone is formed at the base of the petiole. It is composed of a top layer and bottom layer.
The cells in the top layer have weak cell walls and the bottom layer expand in winter and break the cell walls of the top layer, this result in the shedding of leaves.
ii. The loss of chlorophyll may also result in the abscission process.
iii. Hormonal: Abscisic acid hormone stimulates abscission.