Question

The cells of the quiescent centre are characterized by (a) having dense gtoplasm and prominent nudei (b) having light cytoplasm and small nudei (c) ?ividing regularty to add to the corpus (d) dividing regularly to add to tunica.

Short answer

The cells of the quiescent centre are characterized by having dense cytoplasm and prominent nuclei; hence, the correct answer is (a).

Step-by-step solution

Identify the Characteristics of the Quiescent Centre

Understanding the characteristics of the cells in the quiescent centre is crucial. The quiescent centre is a region of the meristem in plant roots where the cells are relatively inactive and do not divide frequently. These cells serve as a reservoir of cells that can be recruited for growth when necessary. The typical characteristics of cells in the quiescent centre include having dense cytoplasm and prominent nuclei because they maintain their cellular machinery in a ready state, even though they are not actively dividing.

Review Options and Compare with Established Knowledge

Look at each of the provided options and compare them with the known characteristics of the quiescent centre. Option (a) matches the description of having dense cytoplasm and prominent nuclei; therefore, it seems to be the correct answer. Option (b) mentions light cytoplasm and small nuclei, which is not typically characteristic of the quiescent centre. Options (c) and (d) both mention regular division, which contradicts the nature of the quiescent centre which divides infrequently.

Select the Correct Answer

Based on the understanding and established characteristics of the quiescent centre, the correct option is the one that mentions dense cytoplasm and prominent nuclei. Therefore, the answer is option (a).

Key concepts

Dense Cytoplasm

Cells with dense cytoplasm are an indicator of high metabolic activity required to maintain cellular functions. Dense cytoplasm features a rich concentration of organelles, ribosomes, and various macromolecules that are crucial for a cell's viability and readiness to divide or differentiate when the need arises.

In the quiescent centre of plant roots, the cells are not actively dividing, but their dense cytoplasm suggests that they retain the capacity for rapid response to damage or growth signals. Think of these cells as 'on standby', equipped with all the necessary tools for action, stored compactly within their confines.

Prominent Nuclei

The nucleus is the command center of a cell, containing the genetic blueprints for life processes. When we talk about prominent nuclei, we're highlighting cells with large and clearly visible nuclei, which is often a sign of an engaged and potentially responsive state.

In the context of the quiescent centre, prominent nuclei imply that though the cells are currently inactive, they can swiftly spring into action, initiating DNA replication and cell division if the conditions or signals demand it. This readiness is pivotal for plants to maintain and repair root tissue as needed.

Meristem in Plant Roots

Plant meristems are regions of undifferentiated cells analogous to stem cells in animals. These cells possess the remarkable potential to specialize and form different tissue types. The meristem in plant roots, specifically, is tasked with root growth and regeneration.

Although the quiescent centre's cells are in a dormant state, they are surrounded by more dynamic areas of the root meristem that are constantly dividing, elongating, and differentiating to drive root growth and development. Thus, the quiescent centre acts as a protective hub and a potential source of new cells for the meristem.

Cell Division in Plants

Cell division is the mechanism by which plants grow and heal. It involves a series of steps where a single cell divides into two daughter cells that may differentiate into various cell types. This process is meticulously regulated, as uncontrolled division can lead to detrimental consequences, like tumorous growths.

Within the meristem, cell division is typically robust, but the quiescent centre follows a different rulebook, dividing sparingly to preserve its cells' potential for future needs. Their infrequent participation in cell division highlights the importance of regulated growth and sustainability in plant biology.