(general) Weak; soft; lax; lacking vigor
(botany) Of a plant cell in an isotonic solution such that the plasma membrane is not pressed tightly against the cell wall, and therefore, is neither swollen (turgid) nor plasmolyzed
The word flaccid describes one that is weak, soft, or lacking vigor. In biological context, it is used in the following terms:
- Flaccid cell. In botany, a flaccid plant cell is one in which the plasma membrane is not pressed tightly against the cell wall. This is observed when the plant cell is placed in an isotonic solution wherein the concentration of solutes in the outside is the same as that in the inside of a plant cell. The plant cell will appear flaccid, and not swollen or plasmolyzed. The plant cell will lose its flaccidity when it is placed in a hypotonic solution and a hypertonic solution. In a hypotonic solution (where the solute concentration of a solution surrounding the cell is lower than that inside the cell), the plant cell tends to allow more water to move into the cell rather than lose it thereby causing the cell to swell and become turgid. In contrast, a plant cell placed in a hypertonic solution (where the solute concentration of a solution outside the cell is higher than that inside the cell) more water leaves than enter the cell and therefore resulting in the plasmolysis of the plant cell.
A related term is flaccidity. Flaccidity is the condition of being flaccid.
Word origin: Latin flaccidus, flacc(ēre) (to grow weak)