Plant growth commences with germination.
Definition:
- Germination: The transition of a seed into a new plant. This process starts with the seed imbibing water, leading to swelling and rupture of its outer layer. This imbibition initiates the metabolic processes crucial for development.
- Germination Stages:
- Moisture Uptake: The seed absorbs water, activating enzymes that metabolize stored food (e.g., starches).
- Radicle Eruption: The embryonic root (radicle) emerges first, establishing the plant in the soil and facilitating water and nutrient absorption.
- Shoot Elongation: Following the radicle, the embryonic stem (shoot) ascends towards the surface to access light for photosynthesis.
Germination Requirements:
- Water: Activates enzymes and softens the seed coat.
- Temperature: An optimal range supports enzyme function and metabolic rates.
- Oxygen: Required for cellular respiration, supplying energy for development.
Post-germination, the plant enters its initial growth phase, characterized by root and shoot elongation, and photosynthesis upon light exposure.