| The leaves of pondweed, a submerged water plant, consist simply of two layers of cells (here both more or less in the plane of focus): a layer of small and one of large chloroplast-rich cells. There is no further differentiation in cell types, while specialized cells like guard cells or vascular vessels are absent. The leaves needs to be so thin to allow enough diffusion of gas (carbon dioxide and oxygen) involved in photosynthesis. |
