How do plants regulate their growth, not only by promoting it but also by signaling to stop it? Provide an example of a hormone that inhibits growth and its effects.

Plants regulate their growth through the balance of growth-promoting and growth-inhibiting hormones. Abscisic acid (ABA) is an example of a hormone that inhibits growth. ABA is synthesized in response to stress, such as drought or high salinity, signaling plants to reduce water loss by closing stomata and inhibiting cell elongation. ABA also plays a role in seed dormancy. By inhibiting processes like cell expansion and promoting stress adaptation, ABA helps plants cope with unfavorable conditions, demonstrating the sophisticated regulatory mechanisms that allow plants to modulate their growth in response to environmental cues.