Plant Cells and Tissues

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Plant Cells and Tissues
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I. General Information

• A. Three main plant cell types
• 1. Parenchyma
• 2. Collenchyma
• 3. Sclerenchyma

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1. Parenchyma

• Can differentiate into all
• cell types
• Living cell, can still divide
• F(x)s
• Plant growth
• Food production (photosynthesis)
• Food storage (e.g. potatoes)
• Wound healing regeneration

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2. Collenchyma

• a. Living cells
• b. Have thicker walls than
• parenchyma
• c. Can form long rope-like fibers
• (e.g. linen)
• d. Can stretch (occur in elongation zones)
• e. F(x) strength, support, elongation

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3. Sclerenchyma

• Usually dead while functioning
• Thick secondary wall, no stretch
• F(x) strength, support
• 2 types
• i. fibers
• ii. Sclereids
• (seed coats,
• nut shells
• fruit)

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I. General Information

• B. Three main types of plant tissue
• 1. Ground tissue
• 2. Dermal Tissue
• 3. Vascular Tissue

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C. Ground tissue

• 1. Surrounded by dermal tissue
• 2. All tissue that is NOT dermal tissue or
  vascular tissue

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C. Ground tissue

• 3. Contains all three types of cells
• (mostly parenchyma)
• 4. Make up most of non-woody
• roots, stems leaves

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C. Ground tissue

• 5. Many f(x)s
• Photosynthesis
• Food storage
• Support

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C. Ground tissue
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D. Dermal Tissue

• 1. General
• Forms the skin
• (outside covering) of a plant
• b. Covers roots, stems leaves
• c. F(x) depends on
• location

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D. Dermal Tissue

• d. Examples
• Epidermis
• Cuticle
• Root Hairs
• Stomata
• Cork

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D. Dermal Tissue

• 2. Epidermis
• a. Parenchyma
• b. Usually ONE
• cell thick
• c. Outer protective
• covering of young
• mature woody plants

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D. Dermal Tissue

• 3. Cuticle
• Waxy layer secreted
• by
• epidermis
• b. F(x)
• prevent dehydration

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D. Dermal Tissue

• 4. Root Hairs
• Modification
• of epidermis
• b. F(x) Absorption
• of water from soil

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D. Dermal Tissue

• 5. Stomata
• a. Location stems
• leaves
• b. F(x) osmoregulation regulation of
• gas exchange

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D. Dermal Tissue

• c. Composition
• two guard cells
• stoma (opening)

Guard cells
stoma
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D. Dermal Tissue
cork

• 6. Cork (bark) (Dead cells)
• F(x)
• i. Replace epidermis in woody stems roots
• ii. Protect
• plant

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E. Vascular Tissue

• F(x)s
• a. Transports water nutrients
• b. Supports the plant

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E. Vascular Tissue

• 2. Two kinds of vascular tissue
• a. Xylem
• b. Phloem

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E. Vascular Tissue

• 3. Xylem
• F(x)
• Conducts
• Water Nutrients UP
• from roots
• (X elevator only goes up)

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3. Xylem

• b. Two kinds of conducting cells
• i. Tracheids
• long, thick-walled scelerenchyma
• Thin separations
• between them

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i. Tracheids

• Water moves
• between them through PITS
• (thin porous
• areas of
• cell wall)

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3. Xylem

• ii. Vessel Elements (members)
• Short, wide sclerenchyma
• No end walls
• No separations btwn. them
• (arranged end to end)
• Not found in Gymnosperms

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Tracheids vs Vessel Elements
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4. Phloem

• F(x)
• conducts the
• Products of
• Photosynthesis
• in every direction
• (P elevator moves in every direction)

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4. Phloem

• b. Two kinds of conducting cells
• 1. Sieve Tube Member
• a. F(x) Conduct sap
• b. Stacked to form long
• SieveTubes

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4. Phloem

• 2. Companion Cells
• a. Parenchyma
• b. F(x) Control movement of
• sap through sieve tubes