Parenchyma is the most abundant plant tissue characterized by thin-walled isodiametric cells, which may be oval, round or polygonal in shape and have cellulosic walls. It is mainly found in soft parts of the plant like root cortex, ground tissue in stem and mesophyll in leaves. Pith, medullary ray and components of xylem and phloem also have parenchyma.
Cells of this tissue have a central large vacuole and a peripherally located nucleus. Parenchyma has loosely arranged cells and serves as food storage tissue. The cells of the parenchyma are turgid that help in maintaining shape and firmness of the plant body. The intercellular spaces allow for gaseous exchange for the metabolically active parenchyma cells. Certain waste products gum, tannin, resins are also stored in parenchyma.