Question

A root hair is formed by (a) Epidermal cell (b) Endodermal cell (c) Cortical cell (d) Pericycle cell

Short answer

The correct answer is (a) Epidermal cell.

Step-by-step solution

Identifying the Cell Types

There are four options provided: Epidermal cell, Endodermal cell, Cortical cell and Pericycle cell. The first step in answering this question is to understand what each of these cell types are and their functions.

Linking Functions with Root Hair Formation

The next step is to link the functions of these cells with the process of root hair formation. Root hairs are structures that mainly help in absorption of water and nutrients.

The Correct Answer

Based on the above understanding, it is clear that Epidermal cells are the ones responsible for root hair formation. These cells are part of the plant's epidermis which is the outermost layer of cells. In the roots, some of these cells project out and grow longer to form root hairs to facilitate better absorption.

Key concepts

Epidermal Cells and Their Role in Plants

Epidermal cells are critical components of a plant's anatomy. They form the outermost layer of the plant, known as the epidermis, providing a protective barrier against physical damage, pathogens, and dehydration. In roots, these cells are particularly important, as they differentiate into root hairs. These are tiny extensions that greatly increase the surface area available for water and nutrient absorption.

• Protection: Acts as a shield for underlying tissues.
• Absorption: Specialized to absorb water and minerals from the soil.
• Preventing Water Loss: Often covered with a waxy cuticle that limits evaporation in above-ground plant parts.

The formation of root hairs is a prime example of how epidermal cells adapt in structure and function to meet the needs of the plant.

Different Types of Plant Cells

Plants consist of various cell types, each with specialized functions. Understanding these can provide insights into their essential roles:

• Parenchyma Cells: Mainly involved in storage and photosynthesis, found throughout the plant.
• Collenchyma Cells: Offer support while allowing for growth, typically found in stems and leaves.
• Sclerenchyma Cells: Provide rigidity and structural support, containing lignin.
• Epidermal Cells: Form the protective outer layer, as discussed earlier.
• Specialized Cells: Such as trichomes, guard cells, and root hair cells, each with unique roles.

These diverse cell types work together, ensuring the plant maintains its structure, performs photosynthesis, transports nutrients, and grows healthily.

Water and Nutrient Absorption in Plants

Plants absorb water and essential nutrients from the soil through their roots. Root hairs, tiny extensions of root epidermal cells, play a key role in this process by increasing the root's surface area:

• Root Hairs: These fine projections enhance the ability of roots to absorb moisture and dissolved minerals.
• Osmosis: Water naturally moves into root hairs through this process, driven by concentration gradients.
• Active Transport: Essential nutrients are taken up actively against concentration gradients, which requires energy.

Root hairs are, therefore, fundamental in ensuring the plant gets sufficient water and nutrients to thrive, affecting overall plant health and growth.

Understanding Root Anatomy

Roots are complex structures designed primarily for absorbing water and nutrients and anchoring the plant. Their anatomy is uniquely suited to these tasks:

• Root Cap: A protective structure at the tip of the root that safeguards delicate tissues during growth.
• Zone of Elongation: Directly behind the root cap, where cells multiply and lengthen, pushing the root through the soil.
• Zone of Maturation: Where cells differentiate and root hairs form, optimizing absorption.
• Vascular Tissue: Located centrally, conducting water, nutrients, and food throughout the plant.

Root hair cells form an integral part of the root’s anatomy, optimizing for maximum absorption and effectively supporting the plant's nutritional needs.