Question

Vessels differ from tracheids (a) In being derived from single cell (b) In having vertical rows of cells with cross walls dissolved (c) In being alive (d) In helping in the conduction of water

Short answer

The correct statements are (b) Vessels have vertical rows of cells with cross walls dissolved and (d) Vessels help in the conduction of water.

Step-by-step solution

Understanding Vessels and Tracheids

Vessels and Tracheids are both types of conducting cells found in plants. Tracheids are a type of water-conducting cell in the xylem which are elongated cells with hard, thick cell walls and are recognized by their tapered ends. Vessels, on the other hand, are also xylem cells, but they form a series of interconnecting tubes. These tubes are made up of a series of cells, called vessel members, arranged end-to-end.

Analyzing statement (a) - Vessels are derived from single cell

This statement is incorrect. Vessels are formed from a series of cells, known as vessel elements, that are lined up end to end, thus creating a tube-like structure.

Analyzing statement (b) - Vessels have vertical rows of cells with cross walls dissolved

This statement is correct. The cells in vessels (each one known as a vessel member) are arranged end-to-end, their end walls are dissolved creating a long open tube which allows water to flow freely.

Analyzing statement (c) - Vessels are alive

This statement is incorrect. Like tracheids, vessels are dead at maturity, as this allows for unrestricted transport of water and dissolved substances.

Analyzing statement (d) - Vessels help in the conduction of water

This statement is correct. Vessels, like tracheids, are components of the xylem, a plant tissue responsible for transporting water and dissolved substances within the plant. Due to the tube-like structure of vessels, they are especially efficient at this task.

Key concepts

Vessel Members

In the fascinating world of botany, vessel members play a crucial role in the transportation of water within plants. These critical components of a plant's vascular system are not standalone entities; instead, they unite to form the conduits known as vessels in the xylem tissue.

Imagine stacking several cylindrical units one atop another, removing the partitions in between, and creating a continuous tube. This is akin to how vessel members align end-to-end, with the end walls, also known as cross walls, dissolved. The result is an open, unobstructed path facilitating efficient water flow. Vessel members, originating from individual cells, undergo a specialization process where they lose their cellular contents, becoming deceased at maturity, which enhances their conductive function.

Tracheids

Tracheids are the more primitive and versatile cousins of vessel members in a plant's xylem. These elongated cells act as the lifeline for water transport in many plant species, particularly in those that do not possess vessels.

The Structure of Tracheids

Imagine tracheids as narrow tubes with thickened, lignified walls that taper at both ends. Unlike vessel members, their walls remain intact, leading to a series of individual, connected cells. Their design creates a pathway where water and nutrients move from cell to cell through pits—small, regulated openings in the cell walls. This mode of conduction is less efficient than that of vessels but is a testament to nature's ability to adapt and ensure survival even in the absence of vessels.

Water Conduction in Plants

Water conduction in plants is nothing short of a marvel, ensuring that every part, from root to leaf, remains hydrated and nutritionally replenished. This ingenious process relies heavily on the xylem tissue, wherein tracheids and vessel members serve as the primary avenues for water movement.

When water enters a plant's roots, it embarks on an upward journey, defying gravity through capillary action and the cohesion-tension theory. The water molecules form a continuous column within the xylem and move upwards, pulled by the evaporation of water at the leaves, a process known as transpiration.

It's important to note that during this epic journey, water carries dissolved nutrients from the soil, which are vital for the plant's growth and development. The architecture of the xylem, with its tracheids and vessels, is a testament to the evolutionary adaptations of plants to efficiently manage and distribute these life-giving waters.