.)!' 



Plant Tissue Culture 



Pig. 17. Tissues from sunflower. Left-hand column, fragments 

 immediately after excision. Right-hand column, the same after two 

 weeks mi nutrient agar. Top: wedge-shaped segment taken from 

 .•in old stem, containing (left) cortex, (center) vascular tissue in 

 eluding cambium, and ( righl i pith. Second row: transverse seg- 

 ment from procambial region where nil parts are approximately 

 equally meristematic. Third row: transverse segment from some 

 wlint older stem. Proliferation is largely from the cambial ring. 

 Bottom: transverse segmenl from an old stem. (From White. 

 I\ l,\. and Braun, A. C. 1942. (•.•nicer Research 2: fig. :'.. Si 



