Page 46 – Fiber-strands in leaves

Page 46 – Fiber-strands in leaves

c. 1940

Fig. 39 . Fiber-strands in leaves. A. Transverse section of the abaxial portion (just beneath the hypodermis) of the transition (i.e., sub-chlorophyllaceous) region of a fully differentiated leaf to show two fiber strands cut in cross section. Each strand is surrounded by a parenchymatous, i.e., the bundle, sheath, the cells of which contain chloroplasts whereas the surrounding parencyma cells are without them. X200. B and C. Transverse sections of the abaxial portion of the basal (i.e., nonchlorophyllaceous) region of a fully differentiated leaf to show, in cross section, a large bundle (in B), and a small bundle, consisting of only 4 fibers (in C). A distinct bundle sheath is to be observed around the larger bundle but this is not so distinct in the case of the small bundle. The walls of the fiber cells have not yet reached their maximum thickness. The starch grains which appear in the bundle sheaths in this region are not shown, bsc, bundle sheath cell; gpc, ground parenchyma cell; is, intercellular space. B and C, X400.