(2-Chloroethyl)trimethylammonii(m Chloride 783 



(2-bromoethyl)trimethylammonium bromide, were necessary to shorten 

 the stem and peduncle of chrysanthemums during the summer*; how- 

 ever, it did not damage the plants or delay flowering at concentra- 

 tions less than IQ-^M. In this respect (2-bromoethyl)trimethylammo- 

 nium bromide was not as active as AMO 1618 (3), 



Combined Action of (2-Chloroethyl)trimethylammonium Chloride 

 and Gibberellins 



The action of the (2-chloroethyl)trimethylammonium chloride 

 derivatives in altering plant growth was the opposite from the action 

 of gibberellin (GA). GA promoted stem elongation, spindly growth, 

 and lighter green coloration of the leaves. (2-Chloroethyl)trimethyl- 

 ammonium chloride, on the other hand, induced growth with shorter 

 stems, stockier plants, and darker green leaves than the untreated 

 plants. When excess gibberellin and (2-chloroethyl)trimethylammo- 

 nium chloride were applied together to wheat seedlings, the action of 

 the gibberellin at first predominated, but later the (2-chloroethyl)tri- 

 methylammonium chloride became effective. When limited amounts 

 of gibberellin and large amounts of the choline analogue were used, 

 a complete variation in height from an elongated, to a normal, to a 

 short and bushy plant could be obtained. The type of growth ob- 

 tained was dependent upon the amount of each chemical applied. 

 Plants may also be treated with either chemical separately for a per- 

 iod of time and then the first growth pattern reversed by treatment 

 with the other chemical. These mutually antagonistic effects between 

 (2-chloroethyl)trimethylammonium chloride and GA have been dem- 

 onstrated with wheat and tomatoes (5, 6). The chemical structures of 

 the two types of compounds are so entirely different that it is diffi- 

 cult to see how the two chemicals could be affecting the same growth- 

 controlling processes. The normal appearance of plants after treat- 

 ment with amounts of both chemicals which would produce their in- 

 dividual effects, however, must be explained. 



Light Intensity 



Plants grow tall or elongated in low light intensities or in re- 

 stricted portions of the visible spectrum. The growth of plants after 

 treatment with (2-chloroethyl)trimethylammonium chloride deriva- 

 tives is similar in appearance to growth in full sunlight, and the 

 growth after gibberellin treatment is similar to that obtained in low 

 light. These qualitative comparisons provide thought for future ex- 

 periments with (2-chloroethyl)trimethylammonium chloride as a sub- 

 stitute for high light intensity in the control of plant development. 



Lindstrom, R. S., and Tolbert, N. E., unpublished. 



