AP BIOLOGY

Detailed explanation-1: -During plant transpiration, water evaporates at the air–liquid interfaces along the pores in the cell walls of mesophyll, epidermal, and guard cells and then diffuses out of a leaf.

Detailed explanation-2: -Effects of Leaf Anatomy on the Distribution of Evaporation. Our model predicted that evaporation is highly concentrated at the lower epidermis and the bundle sheath (BS), with some evaporation occurring from across the mesophyll but especially in the upper spongy mesophyll, just below the palisade/spongy transition.

Detailed explanation-3: -First, the water moves into the mesophyll cells from the top of the xylem vessels. Then the water evaporates out of the cells into the spaces between the cells in the leaf. After this, the water leaves the leaf (and the whole plant) by diffusion through stomata.

Detailed explanation-4: -In terrestrial leaves, air spaces are patterned along the adaxial/abaxial axis, with small spaces between the adaxial palisade mesophyll cells and large spaces between the abaxial spongy mesophyll cells, with particularly large cavities adjacent to stomata.

Detailed explanation-5: -Evaporation from the mesophyll cells produces a negative water potential gradient that causes water to move upwards from the roots through the xylem.