Plant cell the major classes of cells and tissues of roots, stems, leaves, flowers, and reproductive structures, each of which may be composed of several cell types. Parenchyma cells are living cells that have functions ranging from storage and support to photosynthesis (mesophyll cells) and phloem loading (transfer cells). Apart from the xylem and phloem in their vascular bundles, leaves are composed mainly of parenchyma cells. Some parenchyma cells, as in the epidermis, are specialized for light penetration and focusing or regulation of gas exchange, but others are among the least specialized cells in plant tissue, and may remain totipotent, capable of
Plant morphology where the organ is produced. For example, along a new branch the leaves may vary in a consistent pattern along the branch. The form of leaves produced near the base of the branch will differ from leaves produced at the tip of the plant, and this difference is consistent from branch to branch on a given plant and in a given species. This difference persists after the leaves at both ends of the branch have matured, and is not the result of some leaves being younger than others. The way in which new structures mature as they are produced may