After fertilization occurs in a plant, the flower undergoes significant transformations to develop seeds and fruits, which are crucial for the plant's reproduction and dispersal.
Key Transformations Post-Fertilization
Following successful fertilization, a series of four major changes take place within the plant, primarily involving the ovule and ovary. These changes ensure the development of a new plant and its protective structures.
| Structure Before Fertilization | Change After Fertilization | Resulting Structure | Purpose/Role |
|---|---|---|---|
| Primary Endosperm Nucleus | Develops rapidly | Endosperm | Provides nourishment to the developing embryo |
| Zygote (Fertilized Egg) | Undergoes cell division and differentiation | Embryo | The rudimentary plant, ready for germination |
| Ovule | Matures and hardens | Seed | Protects the embryo and aids in dispersal |
| Ovary | Develops and ripens | Fruit | Encloses and protects the seeds, assists in dispersal |
Detailed Changes After Fertilization
The processes initiated by fertilization are vital for the perpetuation of the plant species.
1. Endosperm Development
The primary endosperm nucleus, formed during double fertilization, rapidly develops into the endosperm. This nutritive tissue serves as a food source, supplying essential nutrients to the growing embryo within the developing seed. Its development is often initiated before the embryo's to ensure a readily available food supply.
2. Embryo Development
The zygote, which is the fertilized egg, begins to divide and differentiate, developing into an embryo. This embryo is essentially a miniature, immature plant complete with structures like a radicle (embryonic root), plumule (embryonic shoot), and cotyledons (seed leaves). The embryo represents the next generation of the plant.
3. Ovule Maturation into Seed
Concurrently with embryo and endosperm development, the entire ovule undergoes maturation. Its integuments (outer layers) harden and transform into the protective seed coat, while the ovule itself develops into a seed. The seed serves as a dispersal unit, allowing the embryo to survive adverse conditions and germinate when conditions are favorable.
4. Ovary Transformation into Fruit
The ovary, the part of the flower that contains the ovules, enlarges and ripens to become the fruit. The fruit's primary function is to protect the developing seeds and aid in their dispersal, often by attracting animals that consume the fruit and subsequently spread the seeds. The characteristics of the fruit (e.g., fleshy, dry, winged) vary greatly among plant species, reflecting different dispersal strategies.
