Question

The only plant cells without nuclei among the following are (a) Cambium cells (b) Cells of pericycle (c) Xylem parenchyma (d) Sieve tubes

Short answer

The only plant cells without nuclei among the following are Sieve tubes (d).

Step-by-step solution

Understand the Structure of Cambium Cells

Cambium cells are meristematic cells located in vascular plants and can differentiate into a number of different cells. They possess a nucleus.

Understand the Structure of Cells of Pericycle

The pericycle is a layer of cells just inside the endodermis of a plant root that has lateral meristematic activity. Being meristematic, they contain a nucleus.

Understand the Structure of Xylem Parenchyma

Xylem parenchyma are cells that aid in the function of xylem, the water-conducting tissue in plants. These cells also contain a nucleus.

Understand the Structure of Sieve Tubes

Sieve tube elements are part of the phloem tissue in flowering plants that transport sugar and other nutrients. In sieve tube cells, the process of maturation involves the loss of nucleus.

Key concepts

Function of Cambium Cells

In the fascinating world of plant biology, cambium cells play a crucial role in the growth and development of vascular plants. These cells, found in the cambium layer, are a type of meristematic tissue, which means they are actively dividing and are responsible for secondary growth. But what does secondary growth mean for a plant?

Secondary growth refers to the increase in the girth of the plant stem or root as opposed to primary growth which increases the length. Cambium cells are the artists of this process, as they have the remarkable ability to differentiate into various specialized cell types. These include xylem cells, which carry water and nutrients from the roots to the leaves, and phloem cells, which transport sugars and other metabolic products downward from the leaves.

Their placement is strategic – lodged between these two vital tissues, xylem and phloem, in a ring formation. One key aspect of cambium cells is their function in creating new layers of vascular tissues year after year, which is especially apparent in tree trunks where each layer marks a new growth ring. Thus, cambium cells are essential for both the robustness and the longevity of trees.

Role of Pericycle in Plant Roots

Let's delve into the underground world of plant roots, where the pericycle holds a pivotal role. The pericycle is a layer of cells found in the root, just inner to the endodermis, and is significant for a few reasons. Firstly, it is involved in the formation of lateral roots that plants deploy to efficiently explore and exploit soil resources for water and nutrients. This process of lateral root initiation begins deep within the parent root, originating from pericycle cells.

The pericycle doesn't stop there, though. Remarkably, it also retains the ability to become meristematic - akin to plant stem cells - later in the root's development. This means it can keep dividing, which is essential for the plant's adaptability and healing. For instance, if a plant's roots are damaged, the pericycle can give rise to new cells that help repair and regenerate the lost structures. Moreover, it could even transform into vascular cambium tissue if needed, contributing to lateral growth – revealing the pericycle's versatility and importance in a plant's root system.

Xylem Parenchyma's Role in Plants

Xylem parenchyma cells are the unsung heroes within plant xylem, the complex tissue responsible for transporting water from roots to leaves. These parenchyma cells play several support roles, which are vital to the health and efficiency of the xylem vessels. One of their roles is to store vital substances, such as starch and other carbohydrates, that are essential for the plant's growth and survival.

Not only do they store reserves, but xylem parenchyma cells also assist in the sideways movement of water between the vessels and tracheids, which are the other cell types in the xylem responsible for water transportation. This lateral movement of water is crucial, especially when certain pathways are blocked or damaged. Xylem parenchyma cells are living cells that maintain the health of xylem by also playing a part in its repair and maintenance. In the event of air entering the xylem, these cells help to dissolve these air blocks, ensuring the uninterrupted flow of water. Therefore, even though xylem parenchyma may not conduct water themselves, their maintenance and support roles make them key players in the overall functioning of the plant's vascular system.