664 S. ARONOFF 
fraction of the deficient leaves was considerably richer, as shown in Table VIII, 
and this was reflected in the accumulation, in deficient plants, of phenolic compounds, 
notably chlorogenic and caffeic acids. In deficient plants (— B) the levels of these 
phenolic acids ranged up to Io times that of the + B leaves. The sunflower contains 
80% EtOH EXTRACT +B 
==} 
CATION FRACTION +B 
" " -B 
ACTIVITY 

Fig. 3. Time changes of activity in 80% 
fe) | 2 3 a 5 6 7 aq. ethanol extract and free amino acids 
t = 
(DAYS AFTER FEEDING) of — B and + B plants. 
relatively low levels of free amino acids; it is the classical “carbohydrate plant”. 
Nevertheless, — B plants consistently demonstrated a higher free amino acid con- 
tent, a difference which persisted despite variations of overall level with time (Fig. 3). 
The relative excess of free amino acids was found to be characteristic not only of 
sunflower, but of — B lettuce, tomato and radish, as well as peach, apricot, prune 
and cherry. The differences in the leaves, while real, appeared to be much larger 
TABLE WViIIL 
DISTRIBUTION OF RADIOACTIVITY IN BORON-DEFICIENT AND NORMAL PLANTS 
AFTER 3 H PHOTOSYNTHESIS IN CO, 
From PERKINS AND ARONOFF, unpublished results. 





Petr. ether Anionic Cationic ; Neutral 
State — — — — - 
(counts/min) 
+B 63 200 37 400 53 100 II 000 000 
—B 39 400 180 000 74 400 4 400 000 


inthe stems. More intriguing, the most readily identifiable amino acids were the aroma- 
tics, tyrosine, phenylalanine and tryptophane, which were apparent only as traces 
in the corresponding + B stems. We do not know, as yet, the immediate basis for the 
excessive amounts of the aromatic acids in the — B stems. They may arise, of course, 
from proteolysis, or an increased rate of synthesis, or a decreased rate of utilization. 
References p. 666 
