1914] 



ECKERSON— THERMOTROPISM OF ROOTS 



261 



permeability of Sinap 



to 25 



or 30 



remains 



Helianthus 



with increase of temperature 



shows no increase in permeability 



to 40 C. 



Fig. 6. — Phaseolus multiflorus: secondary roots; 

 sucrose curves are identical from 35 to 40 C. 



potassium 



primary roots of Phaseolus multifl 



(fig. 5) show no 



rmeability from 13 to 25 C; while in the secondary 



rmeability 



to2s°C. Both have 



^ 



perm 



to 35° C. 



COMPARISON OF THERMOTROPIC CURVATURES AND PERMEABILITY 



CHANGES 



To show the relation between thermotropic curvatures and per- 

 meability changes, the data given in table I are given in table II 



TABLE II 

 Thermotropic curvatures and permeability variations of roots 



1. 



Raphanus sativus 



2. Pisum sativum 



3- Sinapis alba 



+ 



4- Helianthus annuus . . 



5- Phaseolus multiflorus 

 (primary roots) . . . 



— (secondary 

 roots) 



6. 



/Curvatures 

 \Permeability 

 f Curvatures 

 \Permeability 

 f Curvatures (K) 

 [Permeability 

 /Curvatures (K) 

 \ Permeability 



[Curvatures (W) 

 \Permeability 

 Curvatures (W) 

 Permeability 



7"*5° C. 



10-14 c. 



8-15° C. 



6-15° c. 



14-29 C. 



10-30 c. 



Xone 

 Xone 



Xone 



Xone 

 ?°C 



6-25 C 



+ 



ifr-23°C. 24-36° C. 

 18-24 C. 24-40° C. 

 17-29° C. 



15-35° C. 



30-45 C 



12-20 c 



8-22 C 

 13-20 C 



40-50 



34-5° o 



35-45 

 Xone 



Xone 



1 5-4°° 

 20-40 



C 



c 



c 

 c 



22 



25 



? 



2K 



c 

 c 



( 



40 c 

 -40° c 



40 c. 



-^° 



