By the multiplication of the protoplasts in these merismatic areas the substance of the plant is increased.
In other words, as these growing regions consist of cells, the growth of the entire organ or plant will depend upon the behaviour of the cells or protoplasts of which the merismatic tissues are composed.
As new cells are continually formed in the merismatic mass those which are farthest from the apex gradually cease to divide and a different process of growth takes place in them, which is associated more particularly with the formation of the vacuoles, consequent upon the establishment of coniiderable hydrostatic pressure in them, thus causing the bulk of the cells to be greatly enlarged.