26o 



BOTANICAL GAZETTE 



[SEPTEMBER 



The permeability of roots of Pisum sativum (fig. 2) to potassium 

 nitrate increases from 6° to 15 C; does not change from 15 to 



Fig. 3. — Sinapis alba: the potassium nitrate and glucose curves are identical 

 from 40 to 45 C. 



Fig. 4. — Helianthus annuus: the potassium nitrate and glucose curves are identi- 

 cal from 40 to 45 C. 



Fig. 5. — Phaseolus multiflorus: primary roots; the sucrose and glucose curves are 

 identical from 15 to 25 C. 



23° C; and decreases from 30 to 40 C. The sucrose curve shows 

 that the osmotic pressure is lower at 45 C. than at 40° C. 



