ANATOMY OF ROOTS 



269 



Anatomy of Roots. — If a longitudinal median section be cut through a 

 root tip such as has just been described and examined under a microscope, 

 the anatomy of the several regions of the root can be observed (Fig. 69). 

 The root cap is a more or less thimble-shaped mass of cells covering the end 

 of the meristematic region. It apparently protects the meristematic root tip 



tlf 



H1^ 



wm 



n» 



u-i 



s 

 o 



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 • — 



root cap. 



Fig. 69. Longitudinal section (semi-diagrammatic) through a root tip. {A) region 

 of cell division, (B) region of cell enlargement, {C) lo^ve^ portion of the region of 

 cell differentiation. 



from mechanical abrasion as the root grovrs through the soil. Such abrasion 

 gradually tears off the outer terminal cells of the root cap, but these are re- 

 placed by new root cap cells which are formed by cell divisions occurring in 

 the lowermost layers of the cells of the meristematic region. 



The meristematic tissue of a root tip is composed of small, thin-walled 

 cells with prominent nuclei. As new cells are formed by cell division they 



