LAB #4 – STEMS
Raven 7th p. 547-559; 580-591; 600
Raven 8th p. 579-590; 614-626, 634-635
Introduction
As you go through the next set of images you will see longitudinal sections showing the structure of stem tips as well as cross sections demonstratng primary and secondary growth. Primary growth is basically growth in length due to the activity of the apical meristems of stem and root. The cells of the three primary meristems (protoderm, procambium, ground meristem) are derived from cell divisions in the apical meristem. Secondary growth is growth in girth resulting from cell division in the vascular cambium and cork cambium. Note that stems have specific regions, called nodes, from which buds, leaves and branches arise. See Raven 7th p. 600, Fig. 26-30; Raven 8th p. 635, Fig.26-30, for a helpful summary of primary and secondary growth in stems.