Root Lab Review - Lab Exam 1

Slide 1:
Dicot Root Cross Section 100X		 Note the large area of cortex.  As a review of tissues note the cortex is made up of parenchyma cells, many containing starch grains.  Note the Casparian strip which is a layer of waxy material in the lateral walls of the endodermis cells.  This prevents the movement of water through the walls of the endodermal cells.  Everything inside the endodermis is the stele (vascualr cylinder), while the endodermis and epidermis are part of the cortex.
Slide 2:
Dicot Root Cross Section 400X		 In this slide we are primary observing the stele which is composed of the pericycle, phloem, vascular cambium and xylem.  The endodermis, along with the epidermis (not shown on this slide), is part of the cortex.  The pericycle is made up of meristematic cells which can produce branching secondary roots.  Note the large xylem cells and the location of the vascular cambium between the xylem and phloem.  Where the xylem comes into contact with the endodermis there is no Casparian strip.  These cells are passage cells and facilitate the transport of water and minerals.
Slide 3:
Monocot Root Cross Section 100X		 We observed two different monocot roots in lab, Smilax, left and Zea, right.   Note the cortex, composed of the epidermis, parenchyma cortex and endodermis.   The stele of the monocot includes the pericycle, phloem, xylem and pith, but no vascualr cambium.
Slide 4:
Monocot Root Cross Section 400X		 Both photos focus on the region of the endodermis and the stele.   Note the appearance of the phloem and the location of the pericycle just inside the endodermis.
Slide 5:
Root Tip: Longitudinal Section		 This is not a good picture, but it shows the regions of growth and development in the root tip.
Slide 6:
Root Systems: Fibrous and Tap		 Recognize the difference between the two types.  Review in your text how each develops.
Slide 7:
Specialized Roots		 Aerial, buttress, storage and prop roots