d
(d) : In a plant cell, vacuole may be defined as a non­living reservoir, bounded by a differentially or selectively permeable membrane, the tonoplast. It is filled with a highly concentrated solution called vascular sap or cell sap which contains many dissolved solutes such as organic acids, soluble carbohydrates, soluble nitrogenous compounds as nitrates, enzyme, tannins, chlorides, phosphates, amino acids, alkaloids and anthocyanin pigments.