HISTOLOGY OF PLANT EXTRACELLULAR MATRIX
 
COMPONENT
FOUND IN
MAJOR CHEMICAL COMPONENT
SPECIFIC HISTOCHEMICAL TESTS
EFFECT ON POLARIZED LIGHT
Middle Lamella All Cells Pectin Ruthenium Red Isotropic
Primary Wall All Cells 
Meristematic Cells 
Epidermal Cells 
Sieve Cells 
Sieve Tube Elements 
Parenchyma 
Collenchyma		 Small Randomly Oriented Cellulose (B1-4 Glucose) 1.  Neutral Red 

2.  Acidulated  
Potassium Iodide

 Anisotropic
Secondary Wall Ray Parenchyma 
Vessel Elements 
Tracheids 
Fiber-tracheids 
Fibers 
Sclereids
 Large Parallel Oriented Cellulose that change orientation between layers 1.  Neutral Red 

2.  Acidulated  
Potassium Iodide

 Anisotropic
Lignin 1.  Acidulated Phloroglucinol 

2.  Methylene Blue

 Isotropic
 
Callose Sieve Cells 
Sieve Tube Plates		 B 1-3 Glucose 1.  Analin Blue 

2.  Resorcin Blue

 Isotropic
Suberin Cork Cells 
Guard Cells		 Suberin Sudan IV Anisotropic
Cuticle Endodermal Cells Cutin Sudan IV Anisotropic
Waxes Endodermal Cells Wax Soluble in Xylene Anisotropic