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Primary cell wall
- -Wall structure
- -Physical charactertics
- -Middle lamella
- -Pits/ Plasmodosmata
- Polymer of beta glucose
- -Hydrpgens bond keep the molecule straight and together
- -In cell wall, them are bundle of cellulose molecules.
- -40 molecule/bundle
- Outside the protoplast
- 1.) Cellulose microfibrils
- 2.) Hemicellulose attached to microfibirls- link microfibrils together
- 3.) Pectin- Get linked matrix filling in space.
(Cell Wall)- very flexible and will not stretch
glues adjacent cell wall together
- Pits- hole thru cell wall (in clusters)
- Plasmodosmata- tubular extension of plasma membrane
Secondary Cell Wall
- Component(link microfibrils, no pectin)
- -Lignin: Phenyl propane alcohol (Monomer of lignin)
- -Not stretchable,stiff, elastic
- Primary tissue(ground tissue, Epidermal, Vascular)
- Secondary tissue
- - primary cell wall (thin)
- -Function: metabolic
- - primary cell wall varying thickness (thick and thin)
- -Resident (flexible) support
- -primary and secondary cell wall (thick)
- -Support, water transport
- -Shell (protection)
- -Fibers: long, narrow
- -Sclends: Short,Thick
- Oridinary epidermal cells
- Guard cells
- Xylema.)Tracheary element (primary and secondary cellwalls)
- - tracheids: no protoplasts, water through secondary cell wall pits and crosses primary cell wall.
- - vessel element: No primary cell wall in the Pits than tracheids (perforation and shorter and wider than tracheids)
- b.) Fibers
- C.) Collwnchyma
- d.) Parachyme
- PhloemA.) sieve tube members
- B.) companion cell
- C.) Fiber
- (A,B, and C is sugar condition)
- D.) Collenchyma
- E.) Parenchyma
Functions of Secondary Growth
Meristems: Embryonic tissue regions, primarily concerned with formation of new cells. (primary and secondary)
procambium :A primary meristematic tissue that gives rise to primary vascular tissues.
vascular cambium: A cylindrical sheath of meristematic cells that divides toproduce secondary phloem and secondary xylem.
secondary growth: In plants, growth derived from secondary or lateralmeristems, the vascular cambium and cork cambium, that results in anincrease in girth; in contrast to primary growth, which results in an increase in length.
periderm: Outer protective tissue thatreplaces epidermis when it is destroyed during secondary growth; includescork, cork cambium, and phelloderm.
heartwood: Nonliving and commonly dark-colored wood in which no watertransport occurs; it is surrounded by sapwood.
sapwood: Outer part of the wood of a stem or trunk, usually distinguished fromthe heartwood by its lighter color; part of woody stem in which conductionof water takes place