C) Meristems based on functions:
On the basis of functions, meristems are divided into following three types:
1) Protoderm:
It is the outermost layer of young growing region which gives rise to epidermis (epidermal tissue system) in developing organs.
2) Procambium:
The cells of young growing region which give rise to primary vascular tissues by their elongation and differentiation are called procambium.
3) Ground meristem:
The portion of young growing region which gives rise to hypodermis, cortex, endodermis, pericycle, medullary rays and pith is called ground meristem.
All such parts together constitute the ground tissue system in a plant.
Functions of meristems:
Meristems are responsible for growth fey addition of new cells in various regions of the plants.
They give rise to new leaves, branches and flowers.
Intercalary meristem helps in elongation of internodes and petioles.
Vascular cambium adds new vascular tissues (Xylem and phloem) since older one becomes nonfunctional.
It also helps in secondary growth, i.e. increase in thickness.
Cork cambium forms protective covering around stems and roots.
