Plant Anatomy - Leaves METHODS: The key to understanding plant anatomy and physiology is to equate structure with function. For this lab, draw Stomata the structure you are observing, label the structure and list its Observe the stomatal complex on this leaf [Slide 31]. What is function. Use your text and the photographic atlases.. the function of this complex? PRIMARY GROWTH: LEAF For each of the slides, find the following tissues and note others as indicated: upper (adaxial) and lower (abaxial [aBaxial = Bottom!]) epidermis; palisade layer, spongy layer (which together constitute the mesophyll); stomata (note whether on adaxial, abaxial or both sides); vascular bundles (leaf veins) with xylem usually above the phloem; bundle sheaths, if present, are often made of fibers; cuticle. Dicot Leaves Acer (maple) [Slide 32 & 27]; shade and sun leaves. In these slides the sections of the leaf grown in the sun are Abscission Zone paired with those of the leaf grown in the shade, or on the shady side of the plant. Compare the leaf structure under Prunus cerasus (sour cherry) LS [Slide 23]; showing initiation these conditions. Note that the shade leaf is thinner, its of leaf abscission near bud. palisade layer is weakly developed, its spongy layer is thinner, and vascular tissue of the midrib (bundle) is correspondingly smaller. In both, note relative positions of xylem and phloem in the smaller bundles, and in the midrib bundle. Conifer Leaves Monocot Leaves Pinus (pine) leaf XS [Slide 29]; is an example of a conifer Grasses [Slide 27];: The mesophyll is not ordinarily divided needle. The structure is very different from that of into palisade and spongy layers in grasses, but there are angiosperm leaves. Note especially: distribution of stomata distinct features of the bundles and the sheaths of (sunken); mesophyll of lobed cells; endodermis; transfusion parenchyma cells around them that help to distinguish two tissue; resin ducts; relative positions of xylem and phloem; major types of photosynthetic pathways found in grasses fibers (if any). (and other plants too): C3 and C4 photosynthesis. Zea mays (maize) is an example of a C4 grass leaf. Cuticle about the same on both sides, and stomata occur on both sides, at least in some specimens. Note bundle sheath of larger, dark cells that distinguishes this as a C4 plant. .