Problem 81 - Objective Biology for NEET

Question

After fertilization (a) Ovule develops into seed (b) Ovary matures to fruit (c) Ovary wall changes to fruit wall (d) All of these

Step-by-Step Solution

Answer

The correct answer is (d) All of these. Each part of the process occurs after fertilization: The ovule develops into a seed, the ovary matures into a fruit and the ovary wall changes into the fruit wall.

Step 1: Understand Fertilization

Fertilization is the process where the male gamete or pollen of a flower merges with the female gamete present in ovule of the same flower or another flower. This results in the formation of a zygote, which develops into an embryo.

Step 2: Ovule transformation after Fertilization

After the process of fertilization, the fertilized ovule begins to grow and transforms into a seed. The seed is actually the plant's way of reproducing its species by producing new plants.

Step 3: Ovary transformation after Fertilization

The fertilized ovary also undergoes changes after fertilization. It gradually matures and develops into a fruit. Therefore, the fruit we eat is actually the matured ovary of a flower.

Step 4: Transformation of Ovary Wall

Simultaneously, as the ovary matures into a fruit, the ovary wall undergoes changes as well. It thickens and changes into the fruit wall, often referred to as the pericarp.

Key Concepts

Ovule to Seed

Once fertilization in plants occurs, there are incredible transformations that take place. One of the main events after fertilization is the transformation of the ovule into a seed. The ovule, which initially housed the female gamete, now contains a zygote formed from the fusion of male and female gametes. This zygote eventually matures into an embryo, which is the central part of the seed, capable of developing into a new plant given the right conditions. Furthermore, the covering layers of the ovule harden and form what is known as the seed coat. This coat provides protection to the developing embryo inside, shielding it from environmental harshness. Seeds play a crucial role in plant reproduction:

• They ensure the continuation of plant species by producing new plants.
• Seeds can remain dormant until conditions are ideal for germination.
• They are equipped with stored nutrients that support embryo growth during early stages.

In this manner, the ovule's transformation into the seed facilitates the plant's lifecycle through reproduction and species survival.

Ovary to Fruit

In addition to the ovule turning into a seed, the ovary undergoes a fascinating transformation post-fertilization. The ovary, part of the flower's reproductive system, matures into what we commonly know as a fruit. This change not only signifies an amazing phase of plant development but is also essential for seed protection and dispersal. Here's how the ovary changes into fruit:

• After fertilization, cellular growth and expansion occur in the ovary, which leads to a gradual but significant size increase.
• Nutritional content accumulates inside the fruit to support seeds once they mature.
• Different mechanisms of fruit maturation ensure seeds are spread effectively by wind, water, or animals.

Essentially, the fruit, which arises from the fertilized ovary, acts as a natural protector and transporter of seeds, aiding their distribution and propagation of new plants. Additionally, fruits represent a vital source of nutrients for many organisms, including humans.

Fruit Wall

Simultaneously with the ovary's development into fruit, the ovary wall undergoes noteworthy changes, forming the fruit wall, commonly referred to as the pericarp. This transformation is integral to the fruit's function and is responsible for its protective hormone-induced characteristics. There are several structural layers in the fruit wall:

• Epicarp: The outermost layer, often providing protection and playing a role in the appearance of the fruit; examples include the skin of grapes or apples.
• Mesocarp: The middle layer, which can be fleshy, as in peaches, or fibrous, as in coconuts; this layer often offers the bulk of edible tissue.
• Endocarp: The innermost layer, surrounding the seed(s); in some fruits like cherries, it hardens to form a pit, while in others, it remains soft.

Each of these layers contributes to the fruit's overall function, whether it's protecting the seeds, attracting animals for seed dispersal, or simply providing nutrients. By understanding these transformations, it's easier to comprehend how plants use intricate processes to ensure survival and reproduction.