What prevents water loss in leaves?

Answer 1

To help restrict water losses to manageable rates, the leaf epidermis layers are usually coated in cutin a waxy substance. The layer of this wax over the epidermis is sometimes called cuticle. The epidermis may have epidermal hairs to provide a boundary layer of humid air over the leaf surface to retard evaporation. Virtually all leaves have stomata, openings, in the epidermal layers to regulate water loss and gas exchange.

Answer 2

In addition to the answers above mine, dicot leaves have most stomata on the underside of the leaf where they are more protected from sun and air currents. Water vapor is not as quick to get out from the leaf's underside.

Some plants have their stomata placed down inside pits which serve to reduce air flow and evaporation/transpiration.

Stomata close at night when they don't need to take in carbon dioxide, so they don't have the stomata open when they don't have to. Kind of like the way you have to open the door to go in or out of the house, but you don't leave it open all the time.

Answer 3

Leaves generally have a waxy layer on the outer surface. Plants that grow in drier area may even have spines or needles to minimize the surface area where water can evaporate.

Answer 4

It depends on the plant.

Waxy surface in some.

Some plants will wilt so they have less surface to the sun.

Answer 5

Stomata close up.