Question

what are photosynthetic roots ? what is their mechanism ?

Answer 1

Photosynthetic roots are adventitious roots which prepare food material by photosybthesis. They are green due to the presence of chlorophyll and aerial.
eg: tenospora

Answer 2

These are green, aerial, adventitious roots which prepare food materials by photosynthesis are also called Assimilatory roots.

examples - Taeniophyllum, Trapa and Tinospora.

These roots absorb moisture(water )from the atmosphere and manufacture food materials by photosynthesis.