Definition - What does Hypertonic mean?
In a solution which is hypertonic, the total dissolved solutes is greater than the dissolved solutes of another solution. In plant cells, the hypertonic environment would be all solute particles and the solution they are dissolved in, on the outside of a plant cell. An osmotic gradient is the difference in concentration of dissolved solutes on either side of a semipermeable membrane. For instance, a plant cell's cell wall is a semipermeable membrane which allows for osmotic pressure, or the pressure of water, to flow from a concentration of high pressure to a concentration of low pressure through the membrane.
MaximumYield explains Hypertonic
The xylem and phloem of a plant conduct water, sucrose and other solutions both upward, and downward through a plant. In order for active transport of dissolved solutes in solution to push water into xylem cells, and then over an osmotic gradient to deliver water to the leaves of the plant, a hypertonic solution is created in the sap of the plant. Water flows upward toward higher levels of concentration and builds up hydrostatic pressure. The hydrostatic pressure allows for solution to flow downward through the phloem to lower pressure further down the plant.