Correct option is C
Explanation-
PLETHORA (PLT) transcription factors play a crucial role in root development, especially in defining the boundary between the meristematic zone (where cells actively divide) and the elongation zone (where cells elongate) in roots. PLT proteins regulate stem cell identity and the maintenance of the root stem cell niche by forming a concentration gradient.
Incorrect options:
Option a - SCARECROW (SCR) – Important for ground tissue patterning and asymmetric cell division, not specifically for delimiting the meristem-elongation boundary.
Option b - SHORT ROOT (SHR) – Works along with SCR for radial patterning in roots but doesn't directly define the meristem–elongation zone boundary.
Option d - SPEECHLESS (SPCH) – Primarily regulates stomatal development in leaves, not root development.
So, Option c (PLETHORA – PLT) is the correct transcription factor for this function.
