Lab 5 -- Monocot Roots

Here are the photos taken by students in class based on their hand sections from young corn roots.  Labels have been added to some of the images.

This first image shows the whole root. You can see how root hairs can be very long and numerous.


The next several images show closer views of the stele




Notice the exarch progression of protoxylem to metaxylem in this next image.


Here's a closer view of a newly forming root hair, where you can see how it is an extension of an epidermal cell (no wall between the epidermal cell and the root hair):


These next two images show the formation (thickening) of the endodermis several centimeters back from the root tip.  Note the U-shaped appearance typical of many monocots.




This image shows the central region of the stele near the root tip, where the large metaxylem vessels are not yet mature and still have cytoplasm.


The next images show the production of branch roots










The next 2 images were made by students using a freezing microtome which helped them produce thinner sections, although more work is involved. Some great views of lateral root formation.




The next 3 images show closer views of the region where the root branch connects to the main root xylem.






These next 3 images show longitudinal views of the corn root.






This image shows a transition between the root and the stem.  Xylem and phloem now appear in large numbers of vascular bundles which are scattered around the center.  The region on the left looks like the base of a leaf curled around the stem with an epidermis on both sides.