HISTOLOGY OF  A LEAF CROSS SECTION ©David B. Fankhauser, Ph.D., Professor of Biology and Chemistry              University of Cincinnati Clermont College, Batavia OH 45103

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This lab is designed to be used as a means of reviewing the use of the binocular microscope.
 

Slide: Sun Leaf Pear, B 669a
 

Scan the entire leaf section using the 4x objective , note major visible features, especially vascular tissue bundles and leaf tissue structure. Find a well-defined vascular bundle (not the central vein), then rotate the 10x objective into place. Finally, examine the vascular bundle with the 40x objective. Note the various classes of cells which you can distinguish. Illustrate the 400x view containing the following labeled features which should be familiar to you from first year biology:
 

epidermis:               epidermal cells, cuticle, stoma, guard cells

mesophyll:               palisade parenchyma, spongy parenchyma, intercellular space

vascular tissues:       vascular bundle, bundle sheath, xylem (large, few) and phloem (small and numerous)

	Cross section of pear leaf at the central vein, 40x
	Cross section of pear leaf central vein, 100x
	Vascular bundle, showing xylem (larger red cells) and phloem (indistinct small greenish cells) wrapped in bundle sheath.
	Smaller vascular bundle with pallisade parenchyma and spongy parenchyma clearly shown.
	guard cells guarding stoma at center bottom.
	guard cells guarding stoma at center bottom.
	guard cells guarding stoma at center bottom.