Movement of Water Across the Leaf

Water moves from the xylem to the mesophyll cells by osmosis.Water evaporates from the mesophyll cells into the air spaces in the leaves.The water then diffuses across the air spaces and through the stomata into the environment down a diffusion gradient.Once the water evaporates from a mesophyll cell, the cell has a lower water potential so water moves from the neighbouring cell into the mesophyll cell by osmosis.The loss of water from the neighbouring cell lowers the water potential of the neighbouring cell so water moves into the neighbouring cell from another cell by osmosis.The lower water potential of the mesophyll cell next to the xylem causes the movement of water from the xylem into the mesophyll cell by osmosis.The evaporation of water from the mesophyll cell into the air spaces establishes a water potential gradient that pulls water up the xylem.