AP BIOLOGY

Detailed explanation-1: -Abscisic acid (ABA) is a plant hormone involved in the response of plants to reduced water availability. Reduction of guard cell turgor by ABA diminishes the aperture of the stomatal pore and thereby contributes to the ability of the plant to conserve water during periods of drought.

Detailed explanation-2: -Abscisic acid (ABA) is a stress hormone that accumulates under different abiotic and biotic stresses. A typical effect of ABA on leaves is to reduce transpirational water loss by closing stomata and parallelly defend against microbes by restricting their entry through stomatal pores.

Detailed explanation-3: -In guard cells, the plant hormone abscisic acid (ABA) inhibits stomatal opening and induces stomatal closure through the coordinated regulation of ion transport.

Detailed explanation-4: -The opening and closing of stomata are controlled by specialized cells called guard cells. The turgor pressure in the guard cells controls the opening and closing of the guard cells. Stomatal pores open when guard cells enlarge as a result of water absorption and close when guard cells shrink.

Detailed explanation-5: -Opening and closing of stomata are controlled by the light intensity, humidity, and carbon dioxide concentration. When the root sense of the plants occurs, in case of any shortage of water, then the release of Abscisic acid, which controls the stomatal closing.