140 Botanical Microtechnique 



sphagnum (not in sand!) , and remove pieces of root from the desired 

 region. Roots grown in a moist chamber or water culture have 

 excessively spongy, fragile cortical parenchyma, unlike the structure 

 found in plants in a more normal environment. Tissues of the tip, 

 the hair zone, and for some distance above, are fixed well in Craf II; 

 the older tough roots must be killed in FA A. The brace roots from 

 field-grown plants may also be used (Fig. 13.10) . Roots of sugar cane, 

 sorghum, and the small grains are processed by the above methods. 



Asparagus roots are obtainable readily from volunteer seedlings 

 that occur in the vicinity of asparagus beds. The softer portions of the 

 root, within 3 cm. of the tip, are killed in Craf II, but older roots that 

 have an impermeable hypodermis and endodemiis must be killed in 

 FAA. The butyl alcohol method is suggested for the harder pieces 



(Fig. 13.10). 



Acorns calamus is almost a classical subject for the monocot root. 

 This water plant is abundant in suitable locations, but material is 

 often inaccessible, and the root has no advantages over Asparagus. The 

 processing methods are identical for these two plants. 



Srnilax hispida root has a remarkably thickened endodcrmis, Avith 

 laminated cell walls impregnated with brown coloring matter. Kill 

 the roots in FAA, and try a batch with the butyl alcohol method, 

 using celloidin if sections cannot be cut in paraflin. Safranin-fast 

 green gives a brilliant contrast in which the prominent endodermis is 

 reddish brown. 



Young dicotyledonous roots are obtained readily from the large- 

 seeded legumes, beans, peas, soybeans, and especially the horse bean, 

 Vicia faba. The early stages, including the emergence of lateral roots, 

 can be obtained from roots grown in a moist chamber of sphagnum, 

 l^hese roots do not become excessively spongy when grown in this 

 manner. The older roots showing extensive secondary growth must be 

 taken from plants grown in soil. Soybean and horse bean shoidd be 

 killed in Craf III. Young roots of the apple are particularly interesting 

 because of the proniiiunt Casparian strips in the endodermis. Material 

 is not so easy to obtain as with plants that can be grown (luicklv from 

 seed. Volunteer seedlings ol aj)ple can be dug uj) (arelully and 

 abundant roots ol \arious ages obtained. Kill the yoinigest roots in 

 Ci;ir ill and woody loots in F.Lt. Trial batches of older roots may 



Tu.. nil-Tiansvcise sections of leaf of Zea: a. photoG;rnphcd at 1 IX with 18mm. 

 Micro lessar. leprodiiced at 2S\: b, detail of uicliome and blade. 



