Cells and Tissues of the Plant Body

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Cells and Tissues of the Plant Body

• Chapter 23

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Origin of Primary Tissues

• Primary growth- formation of primary tissues.
• Primary plant body.

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Growth and Development

• Development- the sum total of events that lead to
  the formation of the plant body.
• Growth- an irreversible increase in size.
• Cell division
• Cell enlargement
• Apical Meristems- regions of tissue at the tips
  of shoots and roots that forms new cells.
• Meristematic tissue.
• Much of the plant undergoes unlimited or
  prolonged growth of the apical meristems
  indeterminate.

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Morphogenesis and Differentiation

• Morphogenesis- the development of form.
• Differentiation- a process by which a relatively
  unspecialized cell undergoes a progressive change
  to form a more specialized cell.

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Internal Organization of the Plant Body

• Tissue- a group of similar cells organized into a
  structural and functional unit.
• Tissue System- a tissue or group of tissues
  organized into a structural and functional unit
  larger units of the plant body.
• There are 3 Tissue Systems
• Ground
• Vascular
• Dermal

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Ground Tissue

• Parenchyma
• Polyhedral to round in shape.
• Occur throughout the plant body.
• Photosynthesis, storage, and secretion.
• Collenchyma
• Elongate in shape.
• Occur beneath the epidermis in young stems.
• Support young growing tissues.
• Sclerenchyma- fibers and sclereids.
• Long or stellate in shape.
• Occur throughout the plant body.
• Support (strengthen) and storage.

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Vascular Tissue 1

• Xylem- principal water-conducting tissue in
  vascular plants dead at maturity lignified.
• Tracheary Elements
• Tracheid- elongate and tapering pits, but no
  perforations seedless vascular plants,
  gymnosperms, and some angiosperms.
• Vessel element- elongate pits and perforations
  angiosperms.

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Vascular Tissue 2

• Phloem- principal food-conducting tissue in
  vascular plants living at maturity not
  lignified.
• Gymnosperm Sieve Elements
• Sieve cell- elongate tapering with sieve
  areas.
• Albuminous cell- elongate tapering delivers
  substances to sieve cells.
• Angiosperm Sieve Elements
• Sieve-tube element- elongate tapering with a
  sieve plate.
• Companion cell- variable delivers substances to
  sieve-tube elements.

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Dermal Tissue

• Epidermis- outermost cell layer of the primary
  plant body.
• Variable in shape guard cells and trichomes.
• Outermost layer of plant body.
• Protective (cuticle and water loss) and
  aeration (stomata).
• Periderm- secondary protective tissues.
• Rectangular in shape cork cells.
• Beneath the epidermis.
• Protective and aeration (lenticels) replaces
  epidermis.