Problem 180 - Objective Biology for NEET

Question

Double fertilization is the unique characterisitic feature of (a) Angiosperm (b) Gymnosperm (c) Pteridophyte (d) Dicotyledons only

Step-by-Step Solution

Answer

The unique feature of double fertilization is characteristic of (a) Angiosperms.

Step 1: Understanding the Concept

Double fertilization is a unique process that takes place in the life cycle of flowering plants or angiosperms. During this process, two sperms from the pollen grain unite with two cells in the ovule. One sperm fertilizes the egg cell to form the zygote, while the other combines with the two polar nuclei to form the endosperm. This process is unique to angiosperms.

Step 2: Identifying the Matching Option

Based on our understanding from Step 1 that double fertilization is characteristic of angiosperms, let's match this with the provided options. The term 'Angiosperm' is stated among the choices.

Step 3: Confirming the Answer

In context to the process of double fertilization, angiosperms are the only plant group that undergoes this reproduction. Hence, option (a) Angiosperm is the correct answer to this question.

Key Concepts

Angiosperms

Angiosperms are commonly known as flowering plants. They are the largest group in the plant kingdom and are vital to many ecosystems. These plants like roses, oaks, and daisies play a crucial role in the process of double fertilization.

Double fertilization occurs exclusively in angiosperms. This process distinguishes them from other plant groups such as gymnosperms and pteridophytes. One key feature of angiosperms is their flowers, which contain reproductive structures. Angiosperms are incredibly diverse and have adapted to a wide variety of habitats.

• They provide food, medicine, and oxygen.
• They are essential in agriculture and horticulture.

Zygote formation

Zygote formation is a critical event that happens during the process of double fertilization in angiosperms. After a pollen grain lands on the stigma of a flower, it grows a pollen tube that travels down to the ovule. This tube allows two sperm cells to move into the ovule.

One of these sperm cells will fertilize the egg cell within the ovule. This fusion results in the formation of the zygote, which will eventually develop into the embryo of the seed. This is crucial because:

• The zygote represents the future generation of the plant.
• It is the starting point for the development of a new plant.
• The zygote contains genetic material from both the male and female parent plants, ensuring genetic diversity.

Endosperm development

Endosperm development is another important process that occurs due to double fertilization in angiosperms. While one sperm fertilizes the egg cell to form the zygote, the other sperm combines with two polar nuclei to form the endosperm.

The endosperm acts as a nutritional source for the developing embryo. It stores nutrients such as starch, proteins, and oils which provide energy and sustenance during germination. This process is unique to angiosperms and is essential because:

• It ensures the seedling has enough resources to grow until it can perform photosynthesis.
• It supports the early stages of plant development by supplying necessary nutrients.

Reproduction in plants

Reproduction in plants can be complex, encompassing a variety of methods and processes across different plant groups. Angiosperm reproduction, however, is characterized by the process of double fertilization. This process involves intricate interactions between pollen and ovules, leading to the creation of seeds and fruit.

Double fertilization is efficient and ensures that a plant invests resources in developing embryos only when egg fertilization is confirmed. Unlike in other plant groups, angiosperms successfully combine two sperm cells during reproduction, leading to the formation of both a zygote and an endosperm.

• This method enhances reproductive success and survival.
• It allows for the production of seeds that are well-nourished and ready to germinate under favorable conditions.
• The process contributes to the ecological success and adaptability of flowering plants.