10 Botanical Microtechnique 



Fig. 2.2— Methods of sulxliv idiiig massive cyliiidiical organs: A-C, sample includes 



portions of all tissues in the axis; D shows the position of pieces removed from a 



large log; E and F, enlarged \ icws of trimmed pieces rcmo\ed from large log. 



Woody twigs having a diameter up to 5 mm. should be cut into 

 15-mm. lengths. Larger twigs should be cut into shorter pieces 

 because the impermeable cork makes penetration by reagents difficult, 

 except through the cut ends. Do not cut the twigs into pieces wath 

 pruning shears or a knife. Rough handling will bruise the camlMum. 

 phloem, the fragile primary cortex and cork cambium, resulting in 

 the separation of the outer layers during sectioning or during stain- 

 ing. Use a razor blade and ctit through the twig by chipping a groove 

 deeper and deeper around \hc twig iinlil il is (tit ihioiigh. \n 

 excellent tool tor cutting twigs into sections is a fine-toothed high- 

 speed saw, such as a rotary dental saw or a jig saw, especially the 

 vibrating diaphragm type. 



To make slides of transverse, radial, and tangential sections in 

 the region of the (anibiinn of old trees, use tissues removed from 

 newly felled logs or limbs having a diameter of at least 10 cm. Cut 

 disks 2 to .S cm. thick from jjortioiis of the log that were not bruised 

 in felling. Wrap the disks in wet burlap and take into the laboratory 



