Lecture on Fabaceae Family

Fabaceae Family Overview

  • Fabaceae (Leguminosae): A family common in many parts of the world, notable for producing legumes.

Sub-families of Fabaceae

  • Mimosoidea: Characterized by monadelphous stamens and flower arrangements in spherical heads.
  • Faboidea: Known for zygomorphic flowers; includes a variety of legumes.
  • Caesalpinoidea: Features distinct floral structures and is often less economically significant compared to others.

Flower Characteristics

  • Unique and diverse floral structures within Fabaceae.
  • Example: Strongylodon macrobotrys shows drastic variations among flower shapes.

Fruit Structure of Legumes

  • Legume: A fruit that develops from the ovary, typically containing several seeds.
  • Anatomical Features:
    • Calyx: Outer whorl of sepals.
    • Ovary Wall (Pericarp): The wall structure of the pod; varies among species.
    • Seeds: Usually contain two cotyledons in legumes.

Types of Legume Pods

  • Diverse shapes and structures. This can include various pod types, like flat, curved, or coiled.
  • Medicago orbicularis and Pterocarpus indicus as examples of diverse pod types.

Germination of Legumes

  • Process: Involves the seed coat breaking, allowing the embryonic plant to emerge.
  • Key Parts:
    • Cotyledons: Initial leaves providing nutrients to the young plant.
    • Hypocotyl: The stem of the seedling; crucial for pushing through the soil.
    • Radicle: The embryonic root that will develop into the primary root.

Growth Stages of a Bean Plant

  • Begins with cotyledons and develops into a foliage leaf split into three leaflets.
  • Growth includes establishing root nodules, which are essential for nitrogen fixation.

Types of Legume Crops

  • Grown as:
    • Grain/Vegetable: e.g., beans and lentils.
    • Ornamentals: These can include flowering types appreciated for aesthetics.
    • Forage: Grown primarily for animal feed.

Nutritional Value of Pulses

  • Pulses are high in protein and fibers, important for a balanced diet.

Symbiotic Relationships

  • Rhizobium Bacteria: Crucial for nitrogen fixation; live in root nodules of legumes, enhancing soil fertility.

Pollination in Legumes

  • Mechanisms involved in the reproduction and fertilization of legumes, including both self-pollination and cross-pollination.

Specific Legume Examples

  • Soya (Soybean): Its cultivation involves knowledge of pollination and growth patterns.
  • Broad Bean: A popular variety, distinguished by its robust growth and pod structure.
  • Peas (Pisum sativum): Includes varieties like garden peas and field peas for different culinary uses.