35_Lecture_Presentation Students

Plant Structure, Growth, and Development

Introduction

  • Authors: Campbell Biology by Reece, Urry, Cain, Wasserman, Minorsky, Jackson.

  • Presentation by: Nicole Tunbridge and Kathleen Fitzpatrick.

Are Plants Computers?

  • Plants like Romanesco exhibit growth that follows a repetitive program.

  • Development in plants is dependent on environmental factors and is highly adaptive.

  • Two Major Groups of Angiosperms: Monocots and eudicots.

Hierarchical Organization of Plants

  • Hierarchy: Consists of organs, tissues, and cells.

    • Organs: Made up of different tissues that carry out specific functions.

    • Tissues: Groups of similar cells fulfilling dedicated functions.

Basic Plant Organs

  • Three Basic Organs: Roots, stems, and leaves.

    • Reflect evolution to gather nutrients from both below and above ground.

    • Roots: Absorb water and minerals.

    • Shooting System: Absorbs CO2 and light.

  • System Organization: Comprised of root and shoot systems.

Structure of Roots, Stems, and Leaves

  • Roots: Essential for anchoring, absorbing minerals and water, and storing carbohydrates.

    • Primary root emerges first and branches into lateral roots to improve stability.

    • Root Systems: Taproot systems (deep roots) vs. fibrous root systems (shallow, spreading).

  • Stems: Comprised of nodes (where leaves attach) and internodes (spaces between nodes).

    • Apical Bud: Growth tip leading to stem elongation, while axillary buds can develop branches or flowers.

Leaf Structure

  • Leaves: Main organs for photosynthesis, composed of a blade and petiole.

    • Facilitates light interception, gas exchange, and heat dissipation.

    • Vein Arrangement: Monocots show parallel veins; eudicots display branching veins.

  • Modified Leaves: Adaptations such as spines, tendrils, and storage leaves for specific functions.

Tissue Systems of Plants

  • Three Tissue Systems: Dermal, vascular, and ground.

    • Dermal Tissue: Protects plant, consists of epidermis, often covered by cuticles to minimize water loss.

    • Vascular Tissue: Includes xylem (transports water/minerals) and phloem (transports sugars).

    • Ground Tissue: Involved in storage, photosynthesis, and structural support.

Plant Cell Types

  • Major Plant Cells: Parenchyma, collenchyma, sclerenchyma, and specialized conducting cells (xylem and phloem).

    • Parenchyma Cells: Least specialized, can divide and differentiate.

    • Collenchyma Cells: Provide flexible support.

    • Sclerenchyma Cells: Rigid, composed of thick lignin-reinforced walls, dead at maturity.

    • Xylem and Phloem Cells: Specialized for water and sugar transport, respectively.

Growth Mechanisms

  • Meristems: Regions of active cell division responsible for plant growth, allowing indeterminate growth.

    • Types include apical meristems (elongation) and lateral meristems (thickness).

  • Secondary Growth: In woody plants, produced by the vascular cambium, allowing for increased diameter of stems and roots.

Conclusion

  • Secondary Growth Significance: It's essential for the structural support and longevity of many plant species, influencing their ecological niches and interactions.

  • Study Focus: Understanding various plant structures and their roles in survival, adaptation, and function is crucial for comprehending plant biology.