It's a critical stage in the life cycle of many plants, marking the transition from a dormant seed to an actively growing seedling. Germination typically involves several key stages.
Activation
Germination begins when a seed encounters the right conditions to break its dormancy and start growing. These conditions usually include a combination of moisture, oxygen, and suitable temperature. Some seeds may also require specific triggers such as exposure to light or certain chemicals.
Water uptake
The first step in germination is the absorption of water by the seed. This process, known as imbibition, causes the seed to swell and become hydrated. Water uptake triggers biochemical changes within the seed, activating enzymes that initiate the germination process.
Activation of metabolic processes
As water enters the seed, metabolic processes within the embryo resume. Stored nutrients, such as carbohydrates, proteins, and fats, are mobilized to provide energy and building blocks for the growing seedling. Enzymes break down complex molecules into simpler forms that the embryo can use for growth.
Radicle emergence
The radicle, which is the embryonic root of the plant, is usually the first structure to emerge from the seed. It grows downward into the soil, anchoring the seedling and absorbing water and nutrients from the surrounding environment. The radicle is followed by the emergence of the hypocotyl, which is the embryonic stem.
Shoot growth
As the radicle elongates and establishes itself in the soil, the shoot begins to grow upward towards the surface. The shoot consists of the stem and the first leaves, known as cotyledons. Cotyledons may emerge above the soil and begin photosynthesis, providing energy for further growth.
Establishment of seedling
As the seedling continues to grow, it develops additional roots, leaves, and stems, eventually establishing itself as a mature plant capable of independent growth and reproduction.
