BIO 1010 Lab 1 - Introduction to the Plant Body

Page 1: Introduction to Plant Body

Essential Definitions

  • Plant Organs: Composed of groups of cells performing similar functions.

  • Tissues: Multiple tissues may exist within an organ.

Page 2: Root Systems

Functions of Roots

  • Anchor the plant to the soil.

  • Absorb minerals and water.

  • Storage of extra sugars, starches, and chemicals.

Types of Root Systems

  • Taproot:

    • A long primary root that penetrates deep into the soil.

    • May have lateral roots branching off.

  • Fibrous Roots:

    • Composed of many small roots, providing a larger surface area for absorption.

Specialized Roots

  • Adventitious Roots: Develop from the stem, providing additional stability (e.g., corn prop roots, tomato plant roots).

Page 3: Internal Anatomy of Roots

Root Structure Overview

  • Root Cap: Protects the growing tip and secretes mucus for movement through soil.

  • Zone of Cell Division: Located just behind the root cap, this area contains actively dividing cells that contribute to root growth.

  • Regions of a Root:

    • Cell Division: Apical meristem, where cells are actively dividing. going through mitosis and producing new cells that will differentiate into various root tissues, supporting overall root development(meristem)

    • Elongation: Cells expand after division.

    • Region of a Cell: This term refers to specific areas within a plant cell that carry out distinct functions. For instance, the nucleus houses genetic material and governs cell activities, while mitochondria are responsible for energy production. These regions work collaboratively to ensure the plant's growth and maintenance

  • Maturation: Area where specific cell types develop, including vascular tissue and root hairs.

Page 4: Leaf Anatomy( plant organs)

External Structure of Stems and Leaves

  • Node: Area where leaves or stems attach to the main stem.

  • Internode: Space between nodes.

Leaf and Stem Components

  • Blade (Lamina): The broad part of the leaf.

  • Petiole: Stem part connecting leaf blade to stem.

  • Sessile Leaves: Leaves that attach directly to the stem without a petiole.

Page 5: Buds and Stipules

Bud Types

  • Axillary Bud: Develops in the axil where the leaf meets the stem.

  • Terminal Bud: At the end of a twig; responsible for new growth.

Special Structures

  • Stipules: Leaf-like appendages; usually temporary and located near the base of the leaf.

Page 6: Leaf Classification and Identification

Leaf Structure Analysis

  • Simple Leaf: Has a single blade and axillary bud. To identify a simple leaf, look for a leaf that has one continuous blade attached to the stem without any subdivisions.

    • Compound Leaf: Comprised of multiple leaflets; can be palmately or pinnately compound. To find a compound leaf, observe that the leaf consists of several small leaflets connected to a single stem. The distinction can be made by checking:

      • Petiole Connection: In compound leaves, each leaflet connects to a central stem called the rachis, whereas a simple leaf has a single petiole.

      • Leaflet Presence: Compound leaves will have more than one leaf blade (leaflet) arising from a single point, while simple leaves will have only one leaf blade.

Leaf Arrangements

  • Alternate: One leaf per node, staggered.

  • Opposite: Two leaves per node.

  • Whorled: Multiple leaves per node.

  • Basal Rosette: Flat mat of leaves (e.g., dandelion).

Page 7: Variability in Leaf Characteristics

Leaf Shapes and Margins

  • Importance of leaf shapes for plant identification.

  • Types of margins: smooth, serrated, lobed.

Venation Patterns

  • Parallel Venation: Veins are parallel to the leaf midrib.

  • Netted Venation: Veins branch and form a network; includes pinnate and palmate types.

Page 8: Internal Leaf Anatomy

Leaf Structure Overview

  • Upper Epidermis: Protective layer, produces waxy cuticle for moisture retention.

  • Palisade Mesophyll: High density of chloroplasts for photosynthesis.

  • Spongy Mesophyll: Irregular cells with air spaces for gas exchange.

Vascular Tissue

  • Bundle Sheath: Surrounds veins, consisting of xylem (water transport) and phloem (sugar transport).

Page 9: Stomata and Gas Exchange

Stomata Function(guard cells protect the stoma)

  • Structure: Guard cells control opening/closing of stomata for gas exchange.

  • Stoma: Singular; stomata is plural.

Mechanisms

  • Stomata open for carbon dioxide influx; close during drought to reduce water loss.

Page 10: Adaptations in Different Environments

Xerophytic Plants

  • Adaptations for dry environments include sunken stomata and trichomes to retain moisture.

Hydrophytic Plants

  • Aquatic plants like water lilies have air spaces for buoyancy and gas exchange; stomata typically on upper surface.

Page 11: Conclusion and Reminders

Pre-Lab Preparation

  • Watch pre-lab video, read lab handout, bring photographic atlas, and complete quiz.

Upcoming Class

  • Next class on Friday; encourages questions and engagement.”} Remember to ask questions if you have any uncertainty about the material! Happy studying! These notes are meant to assist you in your review and understanding of the plant anatomy as we move forward in this course. Good luck!