Plant Morphology and Germination

Plant Morphology

• Morphology is derived from the Latin words "Morphe" (form) and "logos" (study).
• Plant morphology is the science of studying the form of plants.
• It studies the forms and features of different plant organs, including roots, stems, leaves, flowers, seeds, and fruits.

Parts of a Flowering Plant

• The plant body is differentiated into an underground root system and an aerial shoot system.
• The shoot system comprises the stem (including branches), leaves, flowers, and fruits.
• Roots, stems, and leaves are vegetative parts (essential for growth), while flowers are reproductive structures.

Seed Germination

• Seed germination is the process by which a seed develops into a seedling.
• Two types of seed germination are epigeal and hypogeal.

Epigeal Seed Germination

• In epigeal germination, the cotyledons are raised above ground.
• Examples include beans.
• The stages include seed, radicle protruding, seed coat splitting, cotyledons emerging, and first leaf developing.

Hypogeal Seed Germination

• In hypogeal germination, the hypocotyl elongates to push above ground, while the cotyledons stay in the soil.
• Examples include peas.
• The stages include seed, radicle protruding, seed coat splitting, hypocotyl and root lengthening, cotyledons not emerging, and first leaf developing.

Root System

• The root system anchors the plant, absorbs water and minerals, stores food, conducts water, and participates in photosynthesis and respiration.
• Roots also help hold the soil together.

Types of Roots

• Tap roots develop from the radicle of the germinating seed. These roots have a main branch and other supporting branches. They are common in dicotyledonous plants. Common examples are carrots, turnips, etc.

  • Normal taproots are cylindrical and arise from the radicle.
  • Storage taproots are thicker in certain locations for storage, including conical, fusiform, and napiform varieties.

• Adventitious roots originate from any part of the plant body other than the radicle. They are commonly found in monocotyledonous plants.

  • Fibrous roots: are thin and numerous.
  • Prop roots: arise from the stem and support the plant.
  • Storage (tuberous) roots: swell to store food. Examples include sweet potatoes.
  • Climbing roots: help plants climb.
  • Aerial roots: grow above ground.
  • Respiratory roots: grow upward through the soil in areas with oxygen-deficient soil.
  • Haustorial roots: penetrate and absorb nutrients from a host plant.
  • Contractile roots: shrink and pull the plant deeper into the soil.