21. As a result, chloroplasts in mesophyll cells and bundle sheath cells are specialized for each stage of photosynthesis. 22. Some of the species contain silica in their bodies for rigidity and so the mesophyll often has sclerenchymatous idioblasts. 23. Later, the larva mines from the midrib into the mesophyll near the apex of the leaf in an irregular blotch. 24. This enables a bundle-sheath-type area and a mesophyll -type area to be established within a single cell. 25. Photosynthesis depends on the diffusion of Carbon dioxide ( CO 2 ) from the air through the stomata into the mesophyll tissues. 26. Pyruvate is converted back to PEP in the mesophyll cells, and the cycle begins again, thus actively pumping CO 2. 27. This movement lowers the water potential in the leaf airspace and causes evaporation from the mesophyll cell wall menisci of liquid water. 28. Carbon dioxide combines with ribulose bisphosphate and proceeds to the Calvin Cycle . 4 ) Pyruvate re-enters the mesophyll cell. 29. In plants, it is part of the mesophyll , where it forms a layer next to the palisade cells in the leaf. 30. The mine is linear and situated in either the upper or lower mesophyll layer of the leaf tissue, often near the midrib.
