Why abscisic acid also known as stress hormone
Abscisic acid is known as a stress hormone because its levels increase in response to various stressful conditions in plants. These conditions may include drought, salinity, extreme temperatures, and various other environmental stresses.
When a plant experiences stress, such as water scarcity, abscisic acid is synthesized and accumulates in its tissues. This hormone plays a crucial role in initiating and regulating various adaptive responses to stress. Some of the functions of abscisic acid during stress include:
1. Stomatal closure: One of the main effects of abscisic acid is the regulation of stomatal closure, reducing water loss through transpiration. This allows the plant to conserve water during drought conditions.
2. Inhibition of growth: Abscisic acid inhibits the growth of shoots and roots, conserving energy and resources during periods of stress. This helps the plant to prioritize survival rather than growth.
3. Promotion of seed dormancy: Abscisic acid is involved in inducing seed dormancy, preventing germination until favorable conditions for growth are present. This ensures that seeds do not germinate in adverse environments, increasing the chances of successful germination and growth.
4. Induction of stress-related gene expression: Abscisic acid stimulates the expression of various genes that are involved in stress tolerance and protection. This includes genes encoding protective proteins and enzymes that help plants cope with adverse conditions.
Overall, abscisic acid acts as a signaling molecule that helps plants respond and adapt to stressful environments. Its role in regulating various stress responses has led to its classification as a stress hormone.