Cross section through a root of Allium – onion.
This section shows characteristics of a young dicotyledon root with an extensive cortex ans a small central cylinder containing vascular tissues. The cortex consists in thin walled cells of parenchyma. There have polygonal – ovoidal form and show small intercellular spaces. The outermost tissue is the rhizodermis with a few absorbing hairs.
Detail of the cross section. The intercellular spaces in the cortex are evident (red arrow). A few cells of endodermis, the innermost layer of the cortex, are observed with thick walls. These thickenings are three sided (blue arrow). A single large metaxylem is present in the center and small rows of xylem alternate with phloem