Question

A waterproof cuticle a. minimizes water loss through plant surfaces b. inhibits gas exchange between the plant and the air c. both a and \(b\)

Short answer

c. both a and b

Step-by-step solution

Understanding the Concept of Waterproof Cuticle

The cuticle is a waxy layer that covers the surfaces of land plants, primarily leaves and stems. Its main function is to act as a barrier to water loss, conserving water in the plant's tissues.

Analyzing the Function Regarding Water Loss

Given that the cuticle serves as a waterproof layer, it effectively minimizes water loss by reducing the rate at which water evaporates from the plant's surface. Thus, option (a), which states that it "minimizes water loss through plant surfaces," is accurate.

Analyzing the Function Regarding Gas Exchange

The cuticle can also inhibit gas exchange because it coats the leaves where stomata (pores for gas exchange) are located. This would coincide with option (b), which states it "inhibits gas exchange between the plant and the air," as the cuticle can partially block this exchange outside of the openings provided by the stomata.

Evaluating All Given Options

Since the cuticle both minimizes water loss and can inhibit some gas exchange (though not preventing it entirely due to stomata), the comprehensive understanding corresponds with both statements a and b. Therefore, option (c), "both a and b," is the most correct.

Key concepts

Waterproof Cuticle

The waterproof cuticle is a crucial part of a plant's structure. This layer is waxy and glossy, covering the leaves and stems of land plants. It acts as a protective sheet for the plant from various environmental factors.

The primary purpose of the cuticle is to prevent water loss. By forming a barrier on the plant's surface, it stops moisture from escaping into the atmosphere. This feature is vital for plant survival, especially in dry environments where water is scarce.

Another important aspect of the waterproof cuticle is that it provides some protection from various pathogens and helps reflect some of the sunlight. These added benefits enhance the plant's ability to thrive in different conditions.

Gas Exchange

Gas exchange is essential for a plant's health and growth. It involves the movement of gases like oxygen and carbon dioxide in and out of the plant. While the cuticle is protective, it also influences how a plant exchanges gases.

The cuticle itself is not directly involved in gas exchange. However, it affects this process because it covers most plant surfaces. Gas exchange primarily occurs through tiny openings known as stomata, located mainly on the leaves. The stomata can open and close to allow gases to enter and exit.

The presence of the cuticle means that without these stomata, gas exchange would be largely inhibited. Therefore, while it helps conserve water by being impermeable to water vapor, the cuticle also necessitates the presence of stomata to balance between conserving water and allowing for necessary gaseous exchanges.

Water Conservation

Water conservation is a critical aspect of plant survival. Plants need to strike a balance between taking in carbon dioxide for photosynthesis and losing water to the atmosphere.

The cuticle plays an indispensable role in water conservation. By sealing the plant surface, it reduces the rate of transpiration, which is the evaporation of water from plant leaves. This makes a huge difference in how effectively a plant can retain its water.

• It's particularly useful in arid regions where water is a limited resource.
• It helps the plant manage its water reserves more efficiently.

While the cuticle helps prevent water loss, it does not eliminate it completely. Thus, plants have evolved to use their cuticle in conjunction with stomata to smartly manage water use, making it a sofisticate system for water conservation.