1G2 



Burnt;, KegeuLTatiüu ainl its relatioii to traumatroi)isin. 



C. In this set of experiments tlie roots after wounding wero 

 allowed to grow but the traiiinatropic ciirve was prcnnüitecT. For 

 this ])urposo glass tubes of sniall Ijorc were nsod. After being 

 wounded 1 mm from the ti]) \vitli the bot ghiss rod, the roots 

 were inserted into the glass tubes and the preparations were kept 

 in a dampchamber or in water. The tubes varied in length from 

 3 to 8 cm. The roots then must grow from 1 to 6 cm before 

 they can jjroduce the traumatropic curve. 



1. Eight roots were wonndod nnd ])laced in tubos 8 cm long. 

 May 20 th. 1902. 



No. 1. 



9 



Game out and gave curve of 45 degrees. 



o. 



V ^' *? 7) 5? 



The other five died in the tubes 



» 5) r 



grew straight. 



60 



2. Roots wounded as in tlio previous experiment, May 16th. 

 at 10 A. M. 



Fig. 3. 



These roots were allowed to grow either in water 

 or in a damp Chamber and in a short time all tiirned 

 down in answer to gravity. 



A number or experiments were set up to deter- 

 mine the length of time a root can hold the influeiice 

 of the geotropic Stimulus. This was done for the 

 sake of comparison. Uninjured plants whose roots 

 were from 2 to 3 cm in length were placed in plaster- 

 casts and then left in damp sawdust in a horizontal 

 Position from 30 minutes to 15 hom\s. At the end 

 of this time some were reversed so that gravity 

 worked in the opposite direction from what it did 

 at first, others were placed in a vertical position, and 

 still others were taken from the horizontal position 

 and j)laced on the klinostat. They were left under 

 these conditions from one to seven hom\s when they 

 were removed from the casts and all placed on the 

 klinostat in a damp Chamber. The results are shown 

 in the following table. 



All of these roots curved immediately on leaving 

 the tubes except number 6 which gi-ew straight 2 mm 

 and then developed a traumatropic curve. I am not 

 able to account for this fact. 



