Practicing Success

Target Exam

CUET

Subject

Biology

Chapter

Sexual Reproduction in Flowering Plants

Question:

Read the passage and answer the following questions .

The primary cell of the endosperm undergoes repeated divisions, resulting in the formation of a triploid endosperm tissue. This tissue contains reserve food materials that serve as nutrition for the developing embryo. The most common type of endosperm development involves the successive nuclear divisions of the primary endosperm cell, leading to the formation of free nuclei. This stage is known as the free-nuclear endosperm. Eventually, cell wall formation occurs, and the endosperm transitions into a cellular state. The number of free nuclei formed before cellularization varies significantly. In the case of tender coconuts, the liquid known as coconut water is composed of a free-nuclear endosperm consisting of thousands of nuclei, while the surrounding white kernel represents the cellular endosperm. Endosperm can either be fully consumed by the developing embryo before seed maturation (e.g., pea, groundnut, beans) or persist in the mature seed and be utilized during seed germination (e.g., castor and coconut). By observing the seeds of castor, peas, beans, groundnut, and coconut, one can identify the presence of endosperm in each case. The embryo develops at the micropylar end of the embryo sac where the zygote is located. Zygotes typically divide after a certain amount of endosperm is formed, ensuring reliable nutrition for the developing embryo. Although seeds differ greatly, the early stages of embryo development (embryogeny) exhibit similarities between monocotyledons and dicotyledons. A typical dicotyledonous embryo consists of an embryonal axis and two cotyledons. The epicotyl, located above the cotyledons, terminates with the plumule or stem tip. The cylindrical portion below the cotyledons is called the hypocotyl, which ends with the radicle or root tip. The root tip is protected by a root cap. In contrast, embryos of monocotyledons possess only one cotyledon, referred to as the scutellum in the grass family. The scutellum is positioned laterally to the embryonal axis

 

What is the main function of the triploid endosperm tissue?

 

Options:

To provide structural support to the embryo.

To store reserve food materials for the embryo's nutrition.

To facilitate fruit formation

None of these

Correct Answer:

To store reserve food materials for the embryo's nutrition.

Explanation:

The correct answer is Option (2)- To store reserve food materials for the embryo's nutrition.

Endosperm development precedes embryo development. The primary endosperm cell divides repeatedly and forms a triploid endosperm tissue. The cells of this tissue are filled with reserve food materials and are used for the nutrition of the developing embryo. In the most common type of endosperm development, the PEN undergoes successive nuclear divisions to give rise to free nuclei. This stage of endosperm development is called free-nuclear endosperm. Subsequently cell wall formation occurs and the endosperm becomes cellular. The number of free nuclei formed before cellularisation varies greatly. The coconut water from tender coconut that you are familiar with, is nothing but free-nuclear endosperm (made up of thousands of nuclei) and the surrounding white kernel is the cellular endosperm.
Endosperm may either be completely consumed by the developing embryo (e.g., pea, groundnut, beans) before seed maturation or it may persist in the mature seed (e.g. castor and coconut) and be used up during seed germination.