Plant Morphology and Germination

Study Notes

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.

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.

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.

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.

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.

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.