Abscisic acid (ABA) is a plant hormone that plays a vital role in protecting plants against drought. It helps plants survive in unfavorable conditions by regulating various physiological processes. Here are 10 ways in which abscisic acid protects plants against drought:
1. Stomatal closure: ABA triggers the closure of stomata, which are tiny openings on the leaf surface responsible for gas exchange. This reduces water loss through transpiration and helps retain moisture within the plant.
2. Reduction of leaf growth: ABA inhibits the growth of leaves, reducing their surface area and limiting water loss through evaporation.
3. Induces synthesis of protective compounds: ABA stimulates the production of protective compounds like proline and proteins that help plants to maintain cell turgidity and endure water stress.
4. Triggers root growth: ABA promotes root growth, allowing plants to explore a larger soil volume for water uptake, ensuring their survival during drought conditions.
5. Enhances root permeability: ABA increases the permeability of plant cell membranes, facilitating greater water uptake from surrounding soil.
6. Induces gene expression for stress tolerance: ABA activates specific gene expression, leading to the synthesis of stress-responsive proteins that protect plants against drought, including osmoprotectants and antioxidant enzymes.
7. Promotes dormancy and senescence: ABA triggers the dormancy of seeds and buds, allowing them to enter a resting phase during drought until favorable conditions return. It also accelerates leaf senescence, shedding older leaves to conserve water.
8. Regulates abscission: ABA influences the shedding of leaves, fruits, and flowers, preventing water loss and redirecting resources to essential plant parts during drought.
9. Inhibits water channels: ABA inhibits the activity of aquaporins, which are responsible for water transport within the plant. This reduces water movement in the cells, conserving water during drought.
10. Enhances stress tolerance: Overall, abscisic acid acts as a stress hormone, enhancing the plant's tolerance to drought by modulating physiological and biochemical processes to conserve water and protect against dehydration.
How does abscisic acid protect plants against drought?
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