noun, plural: tonoplasts
The cytoplasmic membrane surrounding the vacuole, separating the vacuolar contents from the cytoplasm in a cell.
As a membrane, it is mainly involved in regulating the movements of ions around the cell, and isolating materials that might be harmful or a threat to the cell.
Word origin: Gk tón(os) + -o-, meaning “stretching,” “tension,” “tone” + comb. form repr. Gk plastós formed, molded.
“Also called:” vacuolar membrane.
See also: vacuole.