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Chapter 8 (Vascular Cambium (Interfasicular Cambium (mature parenchyma…

- - - - two elongate cells produced when longitudinal division occurs w/ periclinal wall
        
        one stays as fusiform initial, one differentiates
        
        if outer cell remains cambium, inner develops into secondary xylem
        
        xylem cells increase greatly in diameter pushing cambial cells outward
        
        if inner cell remains cambium, outer develops into secondary phloem
      - periclinal wall: wall parallel to circumference of cambium
      - have thin primary walls & proplastids
    - - also periclinal division
        
        one remains cambial cell, the other differentiates
        
        inner cell: xylem parenchyma
        
        outer cell: phloem parenchyma
        
        mostly produce storage parenchyma & albuminous cells
  - - - can occur in storied rows, or unstoried rows
      - storied cambium: regular horizontal arrangement
      - unstoried cambium: irregular, no horizontal pattern
    - - usually grouped in short vertical rows uniserate, biseriate, or multiseriate
      - uniseriate: one cell wide
      - biseriate: two cells wide
      - multiseriate: multiple cells wide
- - - - cork cambium: cells are cuboidal, inner cell always stays cambium, outer always differentiates into cork cell
        
        in some species, c. cambium creates layer of parenchyma cells on inside
        
        all together compose the periderm
        
        provides temporary protection due to continuous interior growth stretching it circumferentially
        
        aka phelloderm
      - aka phellem cell
      - outer bark: all tissue outside innermost cork cambium
      - inner bark: all secondary phloem b/t vasc. cambium & innermost cork cambium
- - - - contain all cell types in primary xylem, no new
      - arrangment and origin differs from primary
        
        axial system: derived from fusiform initials
        
        always contains tracheary elements
        
        hardwood: contain large amounts of fibers in axial system
        
        term now used to describe all basal angiosperms & eudicots
        
        softwood: all conifers, despite actual hardness
        
        contains fibers for strength & flexibility
        
        some immature tracheary elements & fibers undergo transverse division
        
        differentiate into columns of xylem parenchyma
        
        aka axial xylem parenchyma
        
        crucial temporary water reserve system
        
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        radial system: develops from ray initials
        
        contain only parenchyma in uniseriate, biseriate, or multiseriate masses called rays
        
        ray parenchyma:
        
        store carbohydrates & other nutrients during dormant periods
        
        conduct material over short distances radially w/in wood
        
        2 types of cells
        
        upright cells
        
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        procumbent cells
        
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        in conifers
        
        xylem rays almost exclusively uniseriate
        
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        ray trachieds: horizontal rectangular cells
        
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      - Growth Rings
        
        early wood: first wood formed when quiescence ceases
        
        must have high proportion of wide vessels
        
        in conifers, wide tracheids
        
        late wood: wood produced later in season
        
        lower proportion of vessels, stronger w/ number fibers
        
        in conifers, narrow, thick-walled trachieds
      - Heartwood: dark dry wood at center of log #heartwood/sapwood in root wood/shoot wood
        
        made of broken vessels & trachieds
        
        tylosis: plug of protoplasm pushed by adjacent parenchyma cells into vessels
        
        Sapwood: lighter moist wood at outer region of log, becomes heartwood
      - Reaction Wood
        
        produced in branches in response to stress
        
        in angiosperms, occurs mostly on upper side of branch (known as tension wood)
        
        tension wood: contains gelatinous fibers w/ walls rich in cellulose
        
        exert tension on branch to prevent drooping
        
        in conifers, occurs on underside of branch (known as compression wood)
        
        enriched in lignin, less cellulose
  - - - contains sieve tube members & companion cells in angiosperms
      - contains sieve cells in conifers
- - - - sweet potatoes:
        
        storage parenchyma increased dramatically
        
        numerous vasc. cambium arise not around entire primary xylem but around vessels/vessel groups
        
        cambia after normally, except xylem/phloem produced almost purely parenchyma
        
        new vessels surrounded by new cambium
      - some eudicots produce included phloem
        
        common vasc. cambium produces ordinary secondary xylem & phloem then differentiates into xylem
        
        outermost secondary phloem reactivated & become new vasc. cambium, produces secondary phloem b/t two bands of xylem
  - - - trunk all primary tissue w/ vasc. bundles disturbed through ground tissue
        
        bundle contains only primary xylem & phloem
      - vasc. cambium never develops
      - establishment growth: increase in width & addition of adventitious roots