Problem 214 - Objective Biology for NEET

Question

Assertion: Cuticle prevent loss of water from epidermis Reason: Cuticle is made up of waxy thick layer and cover epidermis

Step-by-Step Solution

Answer

Both the assertion and reason are valid, and the reason is rightly explaining the assertion.

Step 1: Analyzing the assertion

Check the validity of the assertion 'Cuticle prevents loss of water from epidermis'. The cuticle, in a biological context, is a protective, waxy layer that covers the epidermal cells of plants and helps prevent water loss by evapotranspiration. Therefore, the assertion is correct.

Step 2: Analyzing the reason

Next, analyze the reason 'Cuticle is made up of a waxy thick layer and cover epidermis'. The cuticle is indeed composed of a waxy substance (cutin), adding a level of protection and minimising water loss. So, the reason is also correct.

Step 3: Relating the assertion and reason

Cross-check whether the reason is an apt explanation for the assertion. Here, the assertion pertains to the function of the cuticle. The reason provides the structure and location of the cuticle, which explains how it performs its function. Therefore, the reason rightly explains the assertion.

Key Concepts

Cuticle Function

In the fascinating world of plant anatomy, the cuticle plays a crucial role in ensuring the survival of plants. The cuticle is a thin, but incredibly vital layer found on the surface of plant epidermal cells. It acts as a guardian for plants, protecting them from harsh external conditions.
Primarily made of a substance called cutin, which is waxy in texture, the cuticle provides a waterproof barrier that is essential for plant health. This waxy layer prevents water from easily evaporating from the plant's surface, allowing the plant to conserve water.
Moreover, the cuticle can act as a shield against pests and pathogens. It restricts their entry and provides a layer of defense against potential damage. This multifunctional aspect of the cuticle makes it a cornerstone of plant protection and health management.

Epidermis Protection

The epidermis is often referred to as the skin of the plant. It covers the outermost layer of leaves, young stems, and roots, and serves several protective roles. This layer is crucial for safeguarding the inner tissues of the plant.

• Firstly, one of its primary functions is to act as a physical barrier. This prevents harmful microorganisms and external agents from entering the plant.
• Secondly, the epidermis works in tandem with the cuticle to prevent water loss, maintaining the plant's hydration and structural integrity.
• The cells of the epidermis are tightly packed, providing added protection and support.

Without the protective feature of the epidermis, plants would be much more susceptible to environmental stressors and would struggle to maintain their internal balance.

Water Loss Prevention

Water is arguably one of the most critical resources for plant survival. Losing even a small amount of water can have profound effects on a plant's health. Therefore, plants have developed sophisticated means to limit water loss.
One of the key strategies is through the cuticle. As mentioned, this waxy layer effectively reduces water loss by blocking evaporation. The thicker the cuticle, the less water will escape.
Additionally, the structure and function of stomata contribute to water regulation. Stomata are tiny openings on the surface of leaves that allow gases to be exchanged but are also involved in water retention.
These structures open and close as needed to regulate the plant's water levels. The combined efforts of the cuticle and stomata ensure that plants can thrive even in challenging environments by minimizing unnecessary water loss.