170 



Plant Tissue Culture 



Example 1 



* A record is kept of the genealogy of each culture. Thus, Nos. 2 and 3 of passage 

 326 were derived from No. 2 of passage 325, Nos. 11, 12, 13, and 14 of passage 327 were 

 taken as tips of branches of No. 8 of passage 326, etc. Thus, the history of any culture 

 can be traced at will. 



t The length of each culture is recorded as soon after transfer as possible. 



t At the end of the passage (one week), the length of the main axis, the number of 

 brandies, and the length of the longest branch are recorded. Thus, 68 + 9-13 means 

 that the culture had attained a total length of 68 mm. and had formed 9 branches the 

 longest of which was 13 mm. long. 53 + 5 indicates a total length of 53 mm. with only 

 a single branch 5 mm. long. +5-43 indicates that the main axis had not grown at all 

 but that there were 5 brandies the longest of which was 43 mm. long. In this case the 

 length of the longest branch is used in calculating increments. 



§ These figures represent tin' increase during a week's growth, that is, the difference 

 between 15 mm. initial length and 68 mm. final length. 



|| "M" indicates contamination with mold, "B" contamination with bacteria, and 

 "S ' ' indicates that the culture had sunk to the bottom of the flask. 





