Question

The abscission layer is made up of
(a) Cork cells
(b) Sclerenchymatous cells
(c) Collenchymatous cells
(d) Parenchymatous cells

Answer 1

Hint: Cells divide and form a layer of cork cells under the abscission zone. Layers of parenchyma cells are found on both sides of the abscission zone, developing and injecting suberin and lignin into the fresh layer of cork cells under the abscission zone. Suberin and lignin, once the organ is detached, create a durable and waterproof coating for the plant.

Complete answer:
A mature cork cell is non-living and has cell walls that consist of a waxy material called suberin, which is extremely impermeable to gases and water. The cork cell may be filled with air, depending on the species of a woody plant, or may contain traces of lignin, tannins, or fatty acids and may vary in thickness from one to the next.
The connective layer of the zone starts to harden and blocks nutrient transfer between the tree and the leaf. A tear line forms and the leaf is blown away or falls off until the abscission zone has been blocked. The wound is covered by a protective film, keeping water from evaporating and bugs from getting in.
Depending on the species, this stage can occur in a number of ways but often occurs in the abscission region. Detachment can occur when cell wall enzymes are secreted by layers of parenchyma cells to self-digest the middle lamella that keeps the cell walls together in the abscission region. This causes the abscission zone cells to split apart and the leaf or other parts of the plant to drop off. Another way that detachment happens is by water imbibition. In the abscission region, the plant cells can take in a significant amount of water, swell, and ultimately burst, causing the organ to fall apart. When removed, it will expose the protective layer of cork.

Additional information: Abscission is the shedding of an organism's different sections, such as a plant that loses a leaf, fruit, flower, or seed. Abscission is the deliberate shedding of a body section in zoologies, such as the shedding of a claw, husk, or the autotomy of a tail to evade a predator. In mycology, this is the release of a fungal spore. Abscission refers, in cell biology, to the division of two daughter cells at the end of cytokinesis.
So, the correct answer is ‘(a) Cork cell’.

Note: In deciduous trees, at the base of the petiole, an abscission zone, also called a separation zone, is created. It is made up of a top layer of weak wall cells, and a bottom layer that grows in the autumn, destroying the cells' weak walls in the top layer. This helps you to shed the leaf.