A paradermal section is one in
which the microtome knife cuts parallel to the surface of an organ, parallel to
the surface of the leaf in this case. If the leaf were perfectly flat, the
knife might cut a uniform section from one end to the other of the leaf, and
extending uniformly to both sides. But,
leaves tend to be curved or undulate, so the knife cuts into part of the leaf
and misses other parts on the first pass while the cross section
of a typical leaf is divisible into three main parts namely, the epidermis,
mesophyll, and the veins ang longitudinal section is the representation
of an object as it would appear if cut by the vertical plane passing through the
longest axis of the object.
