AP BIOLOGY

Detailed explanation-1: -Some plants limit water loss by closing their stomata when conditions are unfavorable. For example, when the humidity is low, water is more likely to evaporate quickly from the leaf surface, and plants often close or partially close their stomata to maintain a stable water balance in the leaf.

Detailed explanation-2: -Stomata will close if the plant needs water so there won’t be enough water to generate demand for stomatal opening in the guard cells; this reaction lets the plant save water. Stomata regulate the loss of water and the exchange of gas by opening and closing.

Detailed explanation-3: -But when limited water is available in the soil, plants try to prevent water loss. Water loss through transpiration can be reduced by closing the stomata in the leaves using a substance called ABA. When the stomata is closed photosynthesis will decrease because no CO2 can enter through the closed stomata.

Detailed explanation-4: -The cuticle is a layer of epidermis cells in vascular plants. The epidermis cells eject a waxy, water-repelling substance (cutin) that keeps water locked within the plant. Leaf hairs deflect some sunlight and maintain a cooler temperature in the plant.

Detailed explanation-5: -1.1. Plants lose water primarily by gaseous exchange through the stomata on their leaves. ABA is a key hormone that regulates water status and stomatal movement. Under drought conditions, plants produce and accumulate increased amounts of ABA in the guard cells, and this induces stomatal closure to conserve water.