parenchyma cells have a thin primary cell wall and a functional protoplast at maturity.parenchyma cells are present as individual cells or as parenchyma tissue in almost all plant parts,but they are most prevalent in the cortex and pith.the primary cell wall of parenhyma cell is uniformly thin throughout.A diagnostic feature of parenchyma tissue is the presence of air spaces of various sizes between adjoining parenchyma cell that form a continous network for gas exchange throughout the plant. in general,parenchyma cells are many-sided,roughly spherical and come in a broad range of sizes.