What Would Happen If A Salt Solution Was Added To A Slide That An Onion Skin Was On

It is possible to observe the plasmolysis of cells under the microscope. When salt water is added to onion cells, so the cells will lose water due to osmosis, this tin can be observed.

Materials

You need: kitchen knife, ruddy onions, common salt, tap h2o, microscopic slides, cover slips

Method for obtaining a single layer of red onion cells

For this experiment, we can not use the onion peel which is found between the layers of the onion. We need a single layer of pigmented cells. These cells, however, do not separate easily.

We need a thin layer of cells of the ruby-red part of the onion. It is not possible to directly cut a single cell layer, then we need to utilise the "peeling method" to obtain a single layer of cells. Obtain a small-scale slice of onion nearly (1cm ten 1cm). The onion layer is virtually 2mm thick.
With the ruby side of the onion facing y'all, cut beneath the red layer, about one-half way into the onion. This cut does non have to be very thin. There will be about 1mm of onion between the knife and the cherry pigmented layer.
Press the onion firmly confronting the knife with your thumb.
At present tear off or peel away the cerise role of the onion. The cerise layer will become thin. Some red pigment may be released from cleaved cells.
Cut away and discard the thick office of the onion (the identify where the initial cut was placed).
Detect the remaining cells (the thin, peeled part) under the microscope (using a drinking glass slide, water and cover slip, of grade.
Simply consider those cells that are filled with the carmine paint. White cells are broken and take lost the carmine pigment.

Method for Plasmolysis

Make a saturated solution of salt-water
Using a pipette, add together one drib of this solution to the specimen. The salt water should flow beneath the embrace slip. There should exist no need to remove the cover skid to add the salt water
If in that location is also much water beneath the cover slip, and then the salt water will non menses between the cover slip and the slide. In this case utilise tissue paper to withdraw h2o from one side of the embrace skid while adding the salt solution at the other side.
Observe what happens to the reddish pigment inside the cells.

Explanation

Water from the cells moves to the surrounding salt water. The shape of the cells does non change, the cell wall maintains the cell shape. The cell content (the ruby-red part of the cell) starts to shrivel upward. At the aforementioned time it is possible to see that the intensity of the red paint increases because it becomes more full-bodied as h2o is removed (the crimson pigment is not able to move out of the jail cell). The process can be reversed when the common salt water is removed and when distilled water is added.

Advanced variations

Instead of but using concentrated NaCl (table salt) solution, information technology is besides possible to make solutions of dissimilar concentrations. In this example information technology should exist possible to encounter a stronger plasmolysis with the higher table salt concentrations. Try to determine the highest NaCl concentration at which no plasmolysis tin can exist observed. This concentration should then reverberate the water potential of the onion jail cell inside. Alternatively, it is also possible to repeat the experiment with sugar water of different concentrations. Add a drop of rubbing booze to the cells. Booze also has the trend to withdraw water from the cells.