Australian Flora and Fauna: Plants of an Arid Land

Shown is a transverse section of a eucalypt leaf.

Locate the palisade mesophyll, which has cells with numerous chloroplasts containing chlorophyll, and is the main photosynthetic tissue.

You can see that palisade mesophyll is symmetrically distributed in the leaf. This sclerophyllous leaf does not have a distinct upper and lower surface like dorsiventral leaves, but has two identical sides. Such anatomical structure is called isobilateral , and leaves with this structure are termed isobilateral leaves.

Eucalypt leaves are firm and leathery. Note the thick walls of many of the cells. Such thick secondary cell walls consist not only of cellulose, but compounds such as lignin, the main component of wood. Lignin is a polyphenol and is stained blue in this section.

See if you can identify any other structures that are found on both sides of the leaf.