water moves upwards from the roots to the shoots through xylem vessels.water evapourates mainly through the large surface area of the leaves.
water diffuses out through the stomata down a diffusion gradient. water evapourating from the plant in this way is known as transpiration.
the water that exits the leaves by transpiration is replaces by water absorbed through the roots.it is the evapouration of water from the cells in the substomatal cavities of the leaves that provides the force needed to draw water up a plant.
the channels between the cellulose microfibrils in the cell walls act as capilaries which can draw water up them by capillary action caused by surface tension. the stream of water passing through the plant is known as the transpiration stream.
there are cohesive forces between the water molecules from hydrogen bonding. meaning water in narrow tubes sticks together. this is called the cohesion-tension theory.
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