Drought tolerance

Definition

Drought tolerance refers to the ability of a plant to withstand periods of insufficient water without suffering significant harm. This trait is essential for survival in arid environments where water availability fluctuates. Drought-tolerant plants have adapted various physiological, morphological, and biochemical mechanisms to manage water loss and maintain hydration, making them crucial for ecosystems facing climate variability and human-induced changes.

5 Must Know Facts For Your Next Test

1. Drought-tolerant plants often have thicker cuticles on their leaves, which helps reduce water loss through evaporation.
2. Some drought-tolerant species can alter their root systems to grow deeper into the soil, allowing them to access water reserves that other plants cannot reach.
3. The accumulation of osmoprotectants, such as proline and glycine betaine, helps stabilize proteins and cell structures during periods of water scarcity.
4. Drought tolerance can be an inherited trait, with specific genes regulating the physiological responses that enable plants to cope with dry conditions.
5. Certain plants may employ strategies like CAM (Crassulacean Acid Metabolism) photosynthesis, allowing them to open their stomata at night to reduce water loss.

Review Questions

• How do stomata play a role in the drought tolerance of plants?
  • Stomata are crucial for gas exchange and play a significant role in how plants manage water loss during drought conditions. In drought-tolerant plants, stomatal closure can occur during the hottest parts of the day to reduce transpiration and conserve water. This adaptation allows them to maintain hydration levels and continue photosynthesis under limited water availability.
• What morphological adaptations do xerophytes exhibit that contribute to their drought tolerance?
  • Xerophytes display several morphological adaptations that enhance their drought tolerance. These include thickened cuticles on leaves to reduce transpiration, reduced leaf surface area or modified leaves (like spines) to minimize water loss, and deep or extensive root systems that help them access moisture from deeper soil layers. These traits enable xerophytes to thrive in arid environments where other plants struggle to survive.
• Evaluate the importance of understanding drought tolerance in the context of climate change and agriculture.
  • Understanding drought tolerance is increasingly important as climate change leads to more frequent and severe droughts affecting agricultural productivity. By identifying and developing drought-resistant crop varieties, farmers can enhance food security while minimizing resource use. This knowledge enables more sustainable agricultural practices, as it encourages the use of plants that require less irrigation and can adapt to fluctuating weather patterns, thereby supporting ecosystem health and resilience in the face of environmental stress.

Related terms

Stomata:

Small openings on the leaf surface that regulate gas exchange and water loss through transpiration.

Xerophyte: Plants that are specially adapted to survive in dry environments by minimizing water loss and maximizing water uptake.

Water-use efficiency: A measure of how effectively a plant uses water to produce biomass, often improved in drought-tolerant species.