Types discussion: Autism (a developmental brain disorder characterized by impaired social interaction and communication skills, and limited range of activities and interests) is the most characteristic and best studied PDD.
A meristem is the tissue in most plants containing undifferentiated cells (meristematic cells), found in zones of the plant where growth can take place. Meristematic cells give rise to various organs of the plant and keep the plant growing.hese secondary meristems are also known as lateral meristems because they are involved in lateral growth. At the meristem summit, there is a small group of slowly dividing cells, which is commonly called the central zone.
Marestematic TissueMaristematic tissue is composed of actively dividing cells. It is located on the growth point in stem tip. Cambium of dicotyledon, and root tip. Types of Meristematic Tissue Based on the location Meristematic tissue can be distinguished into apical, intercalary, and lateral meristems.Apical meristem is located on the tip of rood and stem. Intercalary meristem is located between mature tissues, e.g at the base of nodes in grass stem.asically, there are three types of primary meristem as follows. 1  Protoderm, which is the outer layer of developing tissues (derived from apical meristem). 2  Ground meristem, Which is meristem which form ground tissues. 3  Procambium, which is meristem which form vascular tissues.