Plant Tissues Lecture Notes

Introduction

• Presenter: Miss Angus
• Topic: Plant Tissues
  • Identification of plant tissues
  • Simplifying study for exams
  • Understanding functions of plant tissues
  • Visual identification under a microscope

Types of Plant Tissues

• Meristematic Tissue
  • Temporary tissue where growth occurs
  • Over time becomes permanent tissue
• Permanent Tissue
  • Types: Parenchyma, Collenchyma, Sclerenchyma
  • Includes vascular tissues: Xylem and Phloem

Meristematic Tissues

• Apical Meristems
  • Located at tips of shoots and roots
  • Responsible for primary growth (lengthening)
• Lateral Meristems
  • Located in the stem (cambium)
  • Responsible for secondary growth (thickening)
  • Provides bark for trees

Permanent Tissues

Epidermis

• Function: Protection
• Structure:
  • Cuticle and upper epidermis protect underlying cells
  • Waxy cuticle prevents water loss
  • Transparent to allow sunlight penetration
• Specialized Cells:
  • Stomata: Guard cells regulate opening and closing
  • Root Hair Cells: Increase surface area for nutrient absorption

Ground Tissues

Parenchyma

• Characteristics:
  • Thin cell wall
  • Intercellular airspaces
• Functions:
  • Packaging tissue, provides sponginess and flexibility
  • Storage and gaseous exchange
• Sub-type: Chlorenchyma contains chloroplasts for photosynthesis

Collenchyma

• Characteristics:
  • Thickened corners
  • Uneven cell wall thickness
• Functions:
  • Provides support and strength
  • Contains chloroplasts (green, photosynthetic)

Sclerenchyma

• Characteristics:
  • Evenly thickened walls
  • Non-living at maturity
• Functions:
  • Provides rigidity and strength
• Types:
  • Fibers: Found in wood and bark
  • Sclereids: Found in nuts and stone fruits

Vascular Tissues

Xylem

• Function: Transport water and minerals
• Direction: One-way (roots to shoots)
• Characteristics:
  • Elongated cells, large lumen
  • Thickened with lignin
  • Pits for lateral water movement
• Types: Vessels (round) and Tracheids (spindle)

Phloem

• Function: Transport sugars
• Direction: Two-way (roots to shoots and vice versa)
• Characteristics:
  • Sieve plates for filtering
  • Companion cells provide energy

Conclusion

• Importance of understanding plant tissues for exams
• Encouragement to subscribe for more biology content on plant videos and grade 10 topics
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