UNIT 12: SECONDARY GROWTH

Study Questions  Lecture Outline
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KEY WORDS

Vascular cambium Anticlinal Hardwood Early wood
Annual Periderm Softwood Late wood
Biennial Phellem Resin ducts Heartwood
Perrennial Phellogen Bordered pit Sap wood
Fusiform initial Phelloderm Diffuse porus Tyloses
Ray initial Suberin Ring porus Reaction wood
Transverse Lenticel Torus Grain
Radial Longitudinal Bark Annual ring Plain-sawed
Periclinal Terminal bud scale scars Dendrochronology Quarter-sawed
Super Trees Fascicular Pulp Wood Knots
Ray Initials Fusiform Initials Radial Transverse
Tangential      


STUDY QUESTIONS

UNIT 12: SECONDARY GROWTH

1 - General term for plants which require 2 years to complete life cycle

2 - Layer which produces secondary xylem

3 - Cambial initial which produces tracheids

4 - Cambial initial which produces vessel elements

5 - Cambial initial which produces cells which are invovlved in lateral        
    conduction

6 - Predominant plane of division of fusiform initials

7 - Root layer which contributes to the completion of the vascular cambium

8 - Cell layer in addition to the epidermis, which is lost as a result of      
    cambial activity

9 - Stem layer which first originates the cork cambium

10 - Layer which forms the periderm

11 - Outer layer which is produced by the cork cambium

12 - Water-proofing material found in cork cells

13 - Layer found in bark but not in the periderm

14 - Botanical structure which appears as long, dark streaks in commercial     
     corks

15 - Type of pit found in gymnosperm wood

16 - Wood section which is parallel to the vascular rays

17 - First formed portion of an annual ring

18 - Central portion of a woody stem which contains oils, gums and resins

19 - Type of wood which is formed when a stem is forced back to an upright     
     position

20 - Structure which is contained in a knot

21 - Primary structure which contributes to wood grain

22 - Plane of plain-sawed lumber


LECTURE OUTLINE

UNIT 12: SECONDARY GROWTH

A - Growth types: annual, biennial, perennial

B - Pattens
   1 - Herbacious - dicots, monocots
   2 - Woody - dicots only
       a - vascular cambium and cork cambium form secondary tissue

C - Cambia
   1 - Vascular Cambium  - produces xylem and phloem
                  Dormant vister - control hormones
   2 - Origin
       a - in root - from pericycle, external tissues lost
       b - in stem - fascicular and interfascicular (pith rays)
            external tissues lost
   3 - Cell types - initials
       a - fusiform initial - conducting elements, elongate
   4 - ray - form xylem and phloem, ray parenchyma

D - Factors influencing amount of cambial division (wood production):
    genetics, fertilizing, tissue culture
   1 - Cork
       a - locations
           (1) stem - initiated in cortex, later in secondary phloem
           (2) root pericycle
   2 - Development - forms periderm
       a - tissues - 
           (1) phellogen - cork cambium    
           (2) phellem (cork) - outside
           (3) phelloderm - inside
   3 - Pattern renewal - determines bark pattern, radial rows of
       compact cells - annual layer.  Lenticils in periderm.
       Commercial cork

E - Wood anatomy and morphology: softwoods - conifers, hardwoods - dicots   
   1 - Sections - radial, transverse, tangential
   2 - Annual rings - early and late wood, ring and diffuse porous,
       dendrochronology
   3 - Heartwood - resins, non-functional
   4 - Reaction wood - leaning produces differential thickening to 
       force upright
   5 - Appearance of wood
       a - color - grain - texture - knot (loose and tight)
   6 - Uses - 
       a - lumber
       b - pulpwood
       c - mulch
   7 - Sawing patterns -
       a - quarter sawed
       b - plain sawed


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