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Water Transport in plants
Root Hair cells: Where water enters plants
Water goes from root into the xylem
Increase surface area = increase in water uptake
Water potential () water travels from high (soil) to low water potential (leaves).
Routes through the root: Symplast pathway and apoplast pathway.
Symplast water travels through living parts of cells (cytoplasm). Neighbouring cells
connected through plasmodesmata (small gaps in cell walls.)
Apoplast non-living (cell walls). Water diffuses through cell walls. When water gets to
epidermis cells path is blocked by Casparian strip. Water then moves to other pathway.
Most used due to least resistance.
After these pathways the water enters the xylem.
Ways water moves up the plant: Cohesion, tension, root pressure.
Cohesion and tension water evaporation in leaves causes tension (suction). Cohesive
properties of water mean that the continuous column of water in the xylem moving up to the
Root pressure a weak pressure that helps to move water already in the xylem further up
Transpiration: loss (evaporation) of water from plants surface
Water evaporates from moist cell walls, gathers in air spaces within leaf.
Open stomata = water moves down concentration gradient and out of the leaf.
Main factors effecting transpiration: Light (more light = faster rate), Temp (high temp =
faster rate), Humidity (Lower humidity = faster rate), Wind (more wind = faster rate).