When is a cell said to be flaccid and when is it called plasmolysed? So far I found that there is a specific relation to osmosis.
Flaccidity in plant cells
The failure to display turgidity especially as seen with plant cells. The suspension of cells from plants in isotonic solutions results in the state termed flaccidity. On a cellular level it represents a lack of pressure of the plasma membrane against the plant cell wall. A more extreme state, termed plasmolysis, is seen given suspension of cells in a hypertonic solution, i.e., as occurs with bacteria suspended in solutions containing high salt or sugar concentrations.
A flaccid cell is one which is in an isotonic solution, this means that the solution and the cell have an equal water conc.. Although there are always water molecules flowing into and out of the cell, they balance each other out. So a cell is referred to as flaccid when it is between being turgid and plasmolysed.
Plasmolysis in plant cells
If a plant cell is placed in a hypertonic solution, the plant cell loses water and hence turgor pressure by plasmolysis: pressure decreases to the point where the protoplasm of the cell peels away from the cell wall, leaving gaps between the cell wall and the membrane and making the plant cell flaccid.