Root Apex: (i) It is found at the tip of main root and its branches. 

(ii) It is derived from radicle part of the embryo and its derivatives, in case of tap root system. 

(iii) In adventitious roots, it is produced from the derivatives of shoot apex. 

(iv) The root apex is sub-terminal because it is covered by the root cap. 

(v) The root apical meristerm (root apex) gives rise to three meristematic region: (i) Protoderm, (ii) Procambium, (iii) Ground meristem. 

(i) Protoderm form epiblema and root cap (calyptra). However, in monocots, the root cap is derived from a special meristematic region at the end of the root called calyptrogen. The cells of the root cap secrete a mucilaginous substance that acts as a lubricant. 

(ii) Procambium produces vascular tissues. 

(iii) Ground meristem forms pith, endodermis and cortex. In many cases, a small region with very low mitotic activity is present in the centre of the root apex, which is called quiescent centre.