Sonoran Desert Plants and Water Use Strategies

These flashcards cover key concepts related to water use, gas exchange, and plant strategies in the Sonoran Desert ecosystem.

What are Xylem and Phloem responsible for in plants?

Xylem is responsible for water transport, while Phloem carries glucose and nutrients.

What does water-use efficiency (WUE) measure?

WUE measures the carbon gained through growth relative to the water lost.

How do stomata function in plants?

Stomata open to allow CO2 in for photosynthesis and close to retain water.

What happens to stomata when there is an unlimited supply of water?

They stay open all the time.

What is the consequence of stomata never opening?

No photosynthesis occurs, leading to O2 toxicity and conservation of water.

What is the tradeoff faced by plants regarding growth rate and water use?

High growth rate (RGR) often leads to high water loss, while low growth rate conserves water.

What strategies do winter annuals use to survive in the Sonoran Desert?

They grow quickly when it rains and minimize water loss to survive through their life cycle.

What does the analogy of a Prius versus a Porsche illustrate about plant strategies?

It illustrates the tradeoff between high water-use efficiency (WUE) and high relative growth rate (RGR).

What factors increase the rate of water loss from stomata?

Temperature, wind, humidity, and surface area of stomata.

What is the relationship between leaf area and transpiration in desert plants?

High leaf area can increase transpiration rates, leading to greater water loss.

Why do plants in the Sonoran Desert likely have small leaf areas?

Small leaf areas help to limit water loss from stomata.

What is the fundamental tradeoff plants must make to carry out photosynthesis?

The tradeoff between maximizing gas exchange for photosynthesis and minimizing water loss.

What is the main challenge of plants during periods of unpredictable rainfall?

Plants must adapt their growth strategies to take advantage of temporary water availability.

What happens to the photosynthetic rate in relation to transpiration under normal conditions?

An increase in photosynthetic rate generally correlates with reduced transpiration and increased plant growth.