
Soil water exists as a thin film in the soil, between soil particles
the concentration of cell sap of root hair is greater than that of the surrounding solution in the soil, thus drawing the water molecules across the cell wall and cell membrane into the root hair by osmosis
water drawn into the root hair cell dilutes the cell sap making it less concentrated than that in the adjacent cortex cells of the root.
due to osmotic gradient water moves from the root hair cells into the cortex by osmosis, from cell to cell by osmosis, across the endodermis by active transport into xylem vessels of the root that conduct water into xylem vessels of the stem into xylem vessels of the leaves Stem
Once in the stem water moves up the plant aided by the narrowness of the xylem vessels (capillary), root pressure, attraction of water molecules to each other (cohesion). Attraction of water molecules to the walls (adhesion) from the stem water enters the xylem of leaves
water moves in the xylem vessels of the stem in a continuous (uninterrupted) water column up to the tree leaves
Leaves once in the leaves water moves into the mesophyll cells by osmosis as water vaporizes from the spongy mesophyll cells their sap becomes more concentrated than the adjacent cells
as the result water flows into the cell from other surrounding cells which in turn takes in water from xylem vessels within the leaf veins
this creates a pull(suction force) called transpiration pull that pulls a stream of water from xylem vessels in the stem and roots
The transpiration pull maintains a continuous column of water from the roots to the leaves.
OR
Soil particles are surrounded by film of water; the cell sap of the root hair is more concentrated than soil water; cell
membrane of root hair acts as a semipermeable membrane; Due to concentration difference between cell sap and water in
the soil; water moves into the root hair by osmosis; this reduces concentration of the cell sap in the root hair; hence water
moves into neighbouring cells (by osmosis); this continues until water reaches the xylem of the root; through cell sap to
cell sap; cytoplasm to cytoplasm; and through intercellular spaces;
Stem.
Once in the xylem water moves up the plant aided by narrowness of the xylem vessels/capillarity; root pressure;
attraction of water molecules to each other/cohesion; attraction of water molecules to the walls/adhesion; from the
stem xylem water enters the xylem of the leaves;
Leaves.
Once in the leaves water enters the mesophyll; and by osmosis moves from cell to cell; it reaches the substomatal
chamber; where it evaporates into the air creating transpirational pull;
simiyu kelly answered the question on September 18, 2017 at 11:48
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