AP BIOLOGY

Detailed explanation-1: -Plants have a waxy cuticle on their leaves to prevent desiccation, or drying out. Carbon dioxide and oxygen cannot pass through the cuticle, but move in and out of leaves through openings called stomata (stoma = “hole"). Guard cells control the opening and closing of stomata.

Detailed explanation-2: -The aerial surfaces of plants are covered by a protective barrier formed by the cutin polyester and waxes, collectively referred to as the cuticle. Plant cuticles prevent the loss of water, regulate transpiration, and facilitate the transport of gases and solutes.

Detailed explanation-3: -Thick waxy cuticle: The cuticle cuts down water loss in two ways: it acts as a barrier to evaporation and also the shiny surface reflects heat and so lowers temperature. Sunken stomata: Stomata may be sunk in pits in the epidermis; moist air trapped here lengthens the diffusion pathway and reduces evaporation rate.

Detailed explanation-4: -The plant cuticle, a cutin matrix embedded with and covered by wax, seals the aerial organ’s surface to protect the plant against uncontrolled water loss. The cutin matrix is essential for the cuticle to function as a barrier to water loss.

Detailed explanation-5: -So the leaf has another adaptation to reduce water loss: the waxy cuticle, so called because it is made out of a water-repellent substance called cutin.