Plant Cells

Meristematic Tissues

  • Found in growing areas; give rise to permanent tissues.

  • Apical meristem

    • Responsible for primary (height) growth.

    • Located at root and shoot tips.

  • Lateral meristem

    • Responsible for secondary (diameter) growth.

    • Includes vascular cambium and cork cambium.

  • Derivatives of apical meristems

    • Plant root tip, vascular cambium, cork cambium.

  • Key outcomes

    • Vascular cambium → secondary xylem and secondary phloem; secondary xylem → wood.

    • Cork cambium → cork; cork + phloem + cork cambium form bark.

Permanent Tissues

  • Simple permanent tissues: one kind of cell.

  • Complex permanent tissues: two or more kinds of cells.

  • Major simple permanent tissues

    • Epidermal tissue (epidermis).

    • Ground tissue.

  • Major complex permanent tissues

    • Phloem.

    • Xylem.

Epidermal Tissues

  • Epidermis covers the entire body of nonwoody and young woody plants; protected by a waxy cuticle to prevent water loss and disease.

  • Root hairs increase absorption capacity in roots.

  • Leaves/stems often have trichomes to reduce water loss and reflect excess light.

  • Guard cells regulate stomatal opening/closing on the lower epidermis.

  • Stomata facilitate gas exchange between the plant and environment.

Ground Tissues

  • Parenchyma

    • Mainly for storage and photosynthesis.

  • Collenchyma

    • Flexible support for growing/immature parts.

  • Sclerenchyma

    • Two kinds: sclereids and fibers.

    • Provides strong, rigid support.

Vascular Tissues (Complex Permanent Tissues)

  • Xylem

    • Conducts water and minerals.

    • Components: Tracheids and Vessel elements.

    • Secondary xylem contributes to wood.

  • Phloem

    • Transports nutrients (sugars) throughout the plant.

    • Components: Sieve-tube elements.

  • Vascular bundles in roots contain both xylem and phloem.

Quick Connectors

  • Ground tissues are fundamental for growth and development; Parenchyma for storage/photosynthesis; Col lenchyma and sclerenchyma for support.

  • Drought context: drought increases tension in xylem, disrupting water transport.

Check Your Understanding (quick prompts)

  • 1) Identify the tissue responsible for transporting water throughout the plant’s body.

  • 2) Where are apical meristems located?

  • 3) Which tissue regulates stomatal opening on the lower leaf epidermis?

Let’s Sum It Up!

  • Plants have two major tissue systems: meristematic and permanent.

  • Meristematic tissues give rise to permanent tissues, which then differentiate into specialized cells.

  • Permanent tissues handle photosynthesis, support, and transport.

  • Apical meristems drive primary growth; lateral meristems drive secondary growth.

  • Ground tissues (fundamental tissues) include parenchyma, col lenchyma, and sclerenchyma for storage and support.

  • Epidermal tissues include the epidermis, guard cells, and trichomes; stomata enable gas exchange.

  • Vascular tissues include xylem and phloem for long-distance transport.