THE EFFECTS AND APPLICATIONS OF OSMOSIS IN EVERYDAY LIFE

(a) Wilting in Plants

1. Excessive use of chemical fertilisers will cause plants to wilt.
2. Fertilisers will dissolve in the soil and cause the soil water to be hypertonic to the root cells of the plant.
3. As a result, water diffuses out of the root cells by osmosis. Plasmolysis occurs and the plant cells become flaccid, causing the plant to wilt.
4. Wilting commonly occurs in non-woody and herbaceous plants.
5. The cells in the plant will promptly recover when water is available. However, if the period of plasmolysis is prolonged, a wilted plant will eventually die.
6. Shortage of water in soil may also lead to wilting in plants.The dried soil becomes more concentrated or hypertonic. Then the plants lose water by osmosis and plasmolysis takes place.




(b) Food preservation

1. The methods of preserving food include drying, pickling, smoking, salting and sugar-curing.
2. Preservation of food is based on the concept of osmosis and plasmolysis.
3. Most food is preserved by using salt or sugar. Examples:
- A fish is preserved by covering it with salt.The moisture around the fish will be hypertonic to the cell of the fish.The water concentration in the cells of the fish exceeds the water concentration outside the fish. Water diffuses out of the fish cells by osmosis. The cells of the fish lose water and undergo crenation. Therefore, the fish can be kept longer.
- In preparing pickles of fruits like mango and papaya, the slices of fruits are immersed in a concentrated sugar solution which is hypertonic to the fruit cells. Water diffuses out of the fruit cells by osmosis into the sugar solution. The cells lose water and not conducive for the growth of microorganisms. Therefore, the fruit can last longer.