In which region of root, cells possess dense protoplasm and maximum plasmodesmatal connections?

The root is covered at the apex by a thimble-like structure called the root cap.

 It protects the tender apex of the root as it makes its way through the soil. 

A few millimeters above the root cap is the region of meristematic activity. The cells of this region are very small, thin-walled and with dense protoplasm. They divide repeatedly. They have numerous plasmodesmal connections.