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Plant Tissues Lecture

Jul 7, 2024

Plant Tissues Lecture by Miss Angus

Introduction

  • Focus on plant tissues
  • Identifying plant tissues effectively for exams
  • Functions and microscopic appearance of plant tissues
  • Suitable for Life Sciences, grades 10 to 12

Types of Tissues

  1. Meristematic Tissue

    • Temporary, found in growth regions
    • Types:
      • Apical Meristems: tips of shoots and roots, responsible for primary growth (lengthening)
      • Lateral Meristems: found in the stem, responsible for secondary growth (thickening)
    • Cambium: ring of tissue for growth in width, crucial for stump and bark formation
  2. Permanent Tissue

    • Longer-lasting, derived from meristematic tissue
    • Types:
      • Epidermis
        • Protective layer, contains cuticle (prevents water loss)
        • Specialized cells: Stomata and Guard Cells (regulate gas exchange), Root Hair Cells (increase surface area for nutrient absorption)
      • Ground Tissues
        • Parenchyma
          • Most abundant, thin cell walls, intercellular airspaces
          • Functions: packaging, storage, gaseous exchange, and allowing water movement
        • Collenchyma
          • Thickened cell walls at corners, provides support
          • Functions: flexibility, support, green stems for photosynthesis
        • Sclerenchyma
          • Uniformly thickened walls, non-living
          • Functions: rigidity, strength
          • Types:
            • Fibers: found in wood and bark
            • Sclereids: found in nuts and stone fruit pits
      • Vascular Tissues
        • Xylem
          • Transports water and minerals in one direction (roots to shoots)
          • Long, thin, large lumen cells, thickened walls with lignin
          • Vessels vs. Tracheids
        • Phloem
          • Transports sugars in two directions
          • Sieve plates, companion cells for nutrient support

Conclusion

  • Summary of plant tissues: Meristematic and Permanent (Epidermis, Ground, Vascular)
  • Importance of understanding structure and function in plant biology