20 Cuticle Waxy layer Controls water loss by “waterproofing” the leaf Upper and lower
21 Epidermis Protects the leaf surface It is the “skin” of the leaf Holds in moisture alsoUpper and lower
22 Control gas entry/exit in leaves Mostly in lower epidermis !
23 Stomata, Pea Leaf Stoma, Vicea sp. (SEM x3,520).
24 MesophyllCells with chloroplasts filled with chlorophyll that carry out photosynthesisPalisade cells are long, upright, erect, and packed like sardines. Most photosynthesis takes place here.Spongy cells are rounded and irregular and loosely packed with a lot of air spaces for movement of gases. Less photosynthesis here because there are fewer chloroplasts.
25 Veins Bundles of vascular tissue Xylem carrying water and nutrients to leaf cellsPhloem carrying food to storage sinksSheathing cells to enclose and protect the vascular tissue