100x Magnification

In this 100x view, cells are becoming more distinct. Notice the outer layer of epidermis. These cells are protective, secreting the cutin that forms the waterproof cuticle layer. Epidermal cells lack chloroplasts so light penetrates through them to deeper layers. The midrib of this leaf is becoming more visible. Supportive and vascular tissues associated with the main vein are found here. You can see different arrangements of cells within the leaf blade. Details of these layers will emerge at higher magnification.

200x Magnification

At 200x look for granularity in cells of the leaf interior. These are photosynthetic mesophyll cells. The uppermost layer(s) contains elongate cells stacked upright. These are the palisade mesophyll. Below these locate the spongy mesophyll, cells with open air spaces between them. Vascular tissues of the vein are becoming visible as are cells of the underlying supportive collenchyma. Look to either side for small veins cut in cross-section. A glandular trichome is visible on the epidermis at top right.

400x Magnification

Moving to 400x magnification provides a closer view of the vascular tissues of the main vein. Look for the thick secondary walls of xylem cells and just below these thin-walled parenchyma cells of phloem. Supporting the vascular tissues above and below are open, thick walled collenchyma cells. To either side of the vein, mesophyll cells can be seen to contain many chloroplasts for photosynthesis.

1000x Magnification

At 1000x magnification you are now clearly seeing differences between cell types. To the upper right locate irregular thickened walls of the supportive collenchyma. Nuclei of some parenchyma cells are displaced to the side by the invisible vacuoles. Mesophyll cells to the upper left contain chloroplasts and these are also displaced by vacuoles. Below these are some vascular tissues, sclerenchyma type xylem cells with thickened secondary cell walls. You are now in the part of the vein that transports water to the leaf.

Microscopy of a Ligustrum Leaf

In this 40x view of a Ligustrum leaf, some features of a typical dicot leaf are visible. Find the well-defined midrib. In addition, some veins are cut at angles. Watch for these at higher magnification. Note that leaves are very thin in comparison to stems and roots! Their design is not for support or strength but rather light gathering capability. The broad blade maximizes surface area for light reception. The thin depth assures that all internal leaf cells will be within areas of light penetration.