note on plasmolysis and steam distillation

Steam distillationis a special type ofdistillation(aseparation process) fortemperature sensitivematerials like naturalaromaticcompounds.

Manyorganic compoundstend todecomposeat high sustained temperatures. Separation by normal distillation would then not be an option, so water orsteamis introduced into the distillation apparatus. By adding water or steam, theboiling pointsof the compounds are depressed, allowing them to evaporate at lower temperatures, preferably below the temperatures at which the deterioration of the material becomes appreciable. If the substances to be distilled are very sensitive to heat, steam distillation can also be combined withvacuum distillation. After distillation the vapors are condensed as usual, usually yielding a two-phase systemof water and the organic compounds, allowing fordecantation

When a plant or animal cell is kept in a hypertonic solution, water from cell sap flows out due to a reverse concentration gradient (concentration gradient pointing out of the cell). As the solution in the external medium is more concentrated, it has more OP and hence water moves out of the cell resulting in shrinkage of the cell volume. If the conditions persist for a long time the cell will die.

This phenomenon of water loss from cells which is akin to exosmosis is called plasmolysis. Wilting of plants noticed under conditions of water scarcity is an indication of plasmolysis of cells. There are three stages in plasmolysis - viz, incipient plasmolysis, evident plasmolysis and final plasmolysis.

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Rinkoo gupta

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