Correct option is D
The correct answer is Casparian strip formation in root endodermis. The formation of the Casparian strip is not a result of programmed cell death (PCD). It is a process that involves the deposition of suberin (a waterproof polymer) and lignin in the cell walls of endodermal cells, particularly at the radial and tangential walls, forming a barrier that regulates the movement of water and solutes in the roots. This is a structural modification of the cell walls rather than the result of cell death.
Information Booster:
- Programmed cell death (PCD) is a controlled process that eliminates cells in a specific, regulated manner to serve various developmental or environmental functions.
- Aerenchyma formation occurs in response to hypoxic conditions in roots, resulting in cells dying to create air spaces.
- Embryonic suspensor cells are non-essential cells that provide nutrients to the embryo and undergo PCD after fulfilling their role.
- Tracheary elements are specialized for water transport and undergo PCD to form hollow tubes after they differentiate.
- Casparian strip formation is a structural change, not the result of cell death. It is essential for controlling the flow of water and nutrients into the vascular system.
Explanation of the Other Options:
Aerenchyma formation in cortical root cells: This is an example of programmed cell death. In response to conditions like waterlogging, certain root cells undergo PCD, leading to the formation of aerenchyma (air spaces) that help the plant survive in flooded environments by improving gas exchange.
Embryonic suspensor cell degeneration: The suspensor cells in plant embryos undergo PCD to aid in the proper development of the embryo. This process is vital for the normal growth and function of the seed.
Tracheary element formation in vasculature: Tracheary elements (such as xylem cells) undergo programmed cell death as part of their maturation process. These cells die and leave behind hollow tubes that conduct water and minerals in the plant.
