Robert A. Steinberg 381 





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Figure 4. Maryland Medium Broadleaf tobacco in asceptic culture il- 

 lustrating the effect on growth of 100 p. p.m. of natural isoleucine. The 

 "D( — )" designation is an error. It should be "L(-|-)." 



preceding data concerned with the metabolic changes accompanying 

 mineral deficiencies. Alterations in metabolism of the leaf lamina were 

 found to be proportional to the degree of abnormality. Localization, 

 it was surmised, operates even in individual leaves, the healthy portions 

 showing relatively little change compared to abnormal portions. 



