Wood Anatomy Lecture V

Axial Cells Derived from Fusiform Initials of Angiosperm Cambium

I.  Vessel Elements
     A. Thick Walled
     B. Cylindrical, connected end to end
     C. Dead at maturity
     D. CW:lumen ratio -> smallest
     E. Bordered pits & perforation plates
     F. Primary function
          1. Transpiration of water & dissolved elements

II. Tracheids
     A. Thick Walled
     B. Elongate
     C. Dead at maturity
     D. CW:lumen ratio -> small
     E. Bordered pits
     F. Primary function
          1. Transpiration of water & dissolved elements
               in sapwood
          2. Waste storage in heartwood

III. Fiber-tracheids
     A. Thick Walled
     B. Elongate (can be septate)
     C. Dead at maturity
     D. CW:lumen ratio -> intermediate
     E. Small bordered pits with slit-like canal that extends
          beyond circular chamber 
     F. Primary function
          1. Transpiration of water & dissolved elements
               in sapwood
          2. Structural support
          3. Waste storage in heartwood

IV. Libriform Fibers
     A. Thick Walled
     B. Elongate (can be septate)
     C. Dead at maturity
     D. CW:lumen ratio -> large
     E. Slit pits  
     F. Primary function
          1. Structural support
          2. Waste storage in heartwood

V. Axial Parenchyma
     A. +-Thin Walled
     B. Rectangular with long vertical axis 
     C. Living cytoplasm at maturity
     D. CW:lumen ratio -> smallest
     E. Simple pits
     F. Primary function
          1. Food and/or waste storage
          
Ray Cells Derived from Ray Initials of Angiosperm Cambium

I. Ray Parenchyma
     A. +-Thin Walled
     B. Geometry
          1. Procumbent = rectangular longitudinal axis
               horizontally oriented in radial direction
          2. Marginal = rectangular longitudinal axis
               vertically oriented in radial direction 
     C. Living cytoplasm at maturity
     D. CW:lumen ratio -> smallest
     E. Simple pits
     F. Primary function
          1. Radial transport of water, elements, food
          2. Food and/or waste storage