THE SHOOT APICAL MERISTEM
(WONDERS OF THE SAM)
 
 
 
 
 WHAT IS A MERISTEM?
    In the early stages of development of the plant embryo all the cells undergo division, but with further growth and development cell division and multiplication become restricted to special parts of the plant which exhibit very little differentiation and in which tissues remain embryonic in character and the cells retain the ability to divide.  These embryonic tissues in the mature plant body are called meristems.
    Meristematic cells are usually thin-walled, more isodiametric in shape than the cells of mature tissues, and relatively richer in protoplasm.
FUNCTIONS OF THE MERISTEM
    All plants have meristems; these are the most important  sites of growth and the originating sites of cell differentiation.  Looking at a meristem under the microscope you can see an amazing variety of things happening.  Many cells are dividing, these will look small and crunched together.  Others are beginning their differentiation process and you can see the formation of secondary walls.  Differentiation is the process a cell undergoes to become specialized for a certain funciton. 
 
 
 
  STRUCTURE OF THE MERISTEM
 
 
 
 
 
CELL ACTIVITY WITHIN THE MERISTEM
 
 
 
 
 

 

 
 
Introduction | Flowers&Fruit | Roots | Stems | Leaves
© Thomas L. Rost 1997
Section of Plant Biology Division of Biological Sciences
UNIVERSITY OF CALIFORNIA, DAVIS