Role Of Abscisic Acid In Drought Condition ( Water Stress Condition ) | Lec. 70 | Plant Physiology

Описание: Abscisic acid (ABA) plays a critical role in plant responses to drought conditions by regulating several physiological and molecular processes to help the plant cope with water stress. Here are the key roles of ABA during drought:

1. *Stomatal Closure:*
ABA is primarily involved in promoting the closure of stomata, the tiny pores on leaves responsible for gas exchange. During drought conditions, ABA levels increase, triggering the guard cells around stomata to close, which reduces water loss through transpiration and helps the plant conserve water.

2. *Gene Expression:*
ABA regulates the expression of drought-responsive genes that help the plant survive water scarcity. These genes are involved in producing protective proteins, such as dehydrins, which protect cells from dehydration and maintain cell turgor.

3. *Root Growth:*
In drought conditions, ABA promotes deeper root growth by inhibiting lateral root development and enhancing primary root elongation. This enables the plant to access water deeper in the soil.

4. *Osmotic Regulation:*
ABA helps maintain osmotic balance by regulating the production of osmoprotectants (like proline and sugars) that help cells retain water and protect against drought-induced damage.

5. *Seed Dormancy and Germination:*
During drought, ABA inhibits seed germination and promotes seed dormancy, preventing seedling growth in unfavorable conditions. This ensures that seeds only germinate when sufficient water is available.

6. *ROS Scavenging:*
ABA activates antioxidant defense systems that scavenge reactive oxygen species (ROS), which are produced in excess during drought stress and can cause oxidative damage to plant tissues.

In summary, ABA is a key hormone that mediates the plant’s adaptive responses to drought by minimizing water loss, enhancing water uptake, protecting cells, and regulating stress-responsive genes.

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