Investigating the water potential of potato discs in different concentrations of sucrose solution

Authors Avatar

Investigating the water potential of potato discs in different concentrations of sucrose solution

Background knowledge

Osmosis can be defined as the movement of water from an area of high water potential to an area of lower water potential through a semi permeable membrane. Osmosis only concerns the movement of water molecules compared with diffusion.

Plant cells depend on water for survival and the main movement of water into plant cells is done through the process of osmosis. Plant cells take up water by osmosis and they start to swell due to the water pressure. Plant cells continue to swell until they are prevented from swelling anymore by the cell wall. At this point the plant is turgid which basically means swollen and hard. This turgid state is very important to plants as it allows them to elongate and absorb more sunlight.

Join now!

When plants are placed in concentrated sugar/salt solutions they lose water by osmosis. This is because the water potential in the plant is now greater then in the solution. As a result water moves from an area of high water potential inside the plant to an area of lower water potential in the solution. As a result of this a process called plasmolysis will occur. During this process the plant loses vital water and becomes permanently damaged.

Tonicity measures the ability of a solution to exert an osmotic pressure upon the membrane. Tonicity involves three solution states which ...

This is a preview of the whole essay