You must have observed that a …

The change in color of the fruits on ripening is a chemical change.
It occurs due to the formation of new enzymes in the fruits.
Enzymes help in ripening of fruits.
An unripe fruit is green because it contains chloroplasts in its skin.
Towards ripening of the fruit,the chloroplasts are changed into chromoplasts which gives the fruit attractive non-green colour.

Plasmolysis is the process in which plant cell will lose the water and turgor pressure after being placed in hypertonic solution. During plasmolysis loss of turgor pressure can force the detachment of protoplast from the cell wall which will result into shrinking of protoplast. Plasmolysis is driven by vacuole. Plasmolysis is a reversible process and addition of hypotonic solution can lead the expansion of protoplast and reinstatement of original turgor pressure. During the plasmolysis majority of osmotic water flows into the central vacuole and drastic changes in protoplast size and shape can affect the subcellular architecture of the plant cell.