Natural auxins 



Figures 3, 4, and 5. Development of curvatures in Artemisia roots under various experimental 

 conditions. Prints reduced to > 0-7. Curvatures were measured directly on the negatives at a magnification 

 of X 35. 



Figure 3. Continuous, unilateral exposure to gravity. Plants not rotated. Photographed at 0, 32, 64, 

 128, 192 minutes, and 10 hours. 



Figure 4. Rotational 1 revolution per O-b minutes {RjO-b) . Upper series: horizontal exposure {E) 

 for 32 mimdes before rotation. Photographed at 0, 32, 64, 128, 192 minutes, and 23-5 hours. Lower 

 series: no horizontal exposure. Photographed at 0, 64, 128, 192 minutes, and 8-5 hours. 



Figure 5. Rotation at 1 revolution per 32 minutes (/?/32). Upper series: horizontal exposure (E) 

 for 32 minutes before rotation. Photographed at 0, 32, 64, 128, 192 minutes, and 22 hours. Lower 

 series: no horizontal exposure. Photographed at 0, 32, 64, 224 minutes, and 22 hours. 



Figures. Development of geotropic curvatures. Ordinate: total curvature (C^^j,). Abscissa: sum 

 of exposure (E) in the horizontal position and the time {T)of rotation at 1 revolution per 0-5 minutes{RI0-5). 

 Upper curve: continuous stimulation, T = 0. 



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