Factors affecting osmosis
There are certain factors that will affect the osmosis rate in plant tissues such as the following
- Solution of concentration
- Length of potato
- Diameter of potato
- Mass of potato
- Temperature
I will investigate how and why these factors affect osmosis.
Reverse osmosis
When a semi permeable membrane separates two water volumes (or other solvent), water will flow from the side of low solute concentration, to the side of high solute concentration. The flow may be stopped, or even reversed by applying external pressure on the side of higher concentration. In such a case is known as reverse osmosis.
The Consequences of Osmosis to plant cells:
Plant cells always have a strong cell wall surrounding them. When the take up water by osmosis they start to swell, but the cell wall prevents them from bursting. Plant cells become "turgid" when they are put in dilute solutions. (Turgid means swollen and hard). The pressure inside the cell rises; eventually the internal pressure of the cell is so high that no more water can enter the cell. This liquid or hydrostatic pressure works against osmosis. Turgidity is very important to plants because this is what makes the green parts of the plant "stand up" into the sunlight.
When plant cells are placed in concentrated sugar solutions they lose water by osmosis and they become "flaccid"; this is the exact opposite of "turgid". If you put plant cells into concentrated sugar solutions and look at them under a microscope you would see that the contents of the cells have shrunk and pulled away from the cell wall: they are said to be plasmolysed.
When plant cells are placed in a solution, which has exactly the same osmotic strength as the cells they are in a state between turgidity and flaccidity. We call this incipient plasmolysis. ("Incipient" means, "about to be").
