56 - = / 56 = . Name _________________________________
Leaf Anatomy
Structure and function are so inter-related that it is difficult to study either one, in isolation of the
other. Use the on-line slides to study leaf structure.
I. A MESOPHYTIC LEAF
A. Examine a cross section of the leaf of lilac (Syringa). There are three major regions: the
epidermis forming a single layer over both surfaces, the ground parenchyma (in this case
called MESOPHYLL), and the vascular system or veins. Study each of these regions.
1. EPIDERMIS. Compare the cells on the upper and lower surface of the leaf for wall
thickness, thickness of cuticle, occurrence of stomata, presence of hairs, etc.
Cell Walls
Cuticle
Stomata
Upper
Epidermis
thick thin thick thin many few
Lower
Epidermis
thick thin thick thin many few
Are there any spaces between epidermal cells other than stomata? yes no
2. MESOPHYLL. The bulk of the tissue in the leaf contains chloroplasts and carries on
photosynthesis. Note the layer of PALISADE parenchyma just below the upper
epidermis.
How many layers of palisade are there? none one more than one
How much of the thickness of the leaf does palisade make up? __________ %
Look carefully at the arrangement of the mesophyll cells.
Is there intercellular space in palisade mesophyll? yes no
The mesophyll between the palisade tissue and the lower epidermis is the
SPONGY parenchyma. How does it compare to the palisade tissue in shape of
cells, number of chloroplasts per cell, volume of intercellular spaces, and total
amount of cell surface exposed to the internal atmosphere? Be sure to examine the
paradermal section before making your final answers!
Palisade
Spongy
Cell Shape elongate spherical elongate spherical
# Chloroplasts more fewer more fewer
Gas Space Volume more less more less
Cell Surface Area more less more less
/20
Docsity.com
