Effect of some (2-chloroethyl) trimethylammonium chloride analogs and other growth retardants on gibberellin biosynthesis in Fusarium moniliforme.

Beginning about 1950, a number of compounds have been describedd which have the property of reducing growth in higher plants. The most widely known and studied of these dwarfing agents or growth retardants are 2-isopropyl-4-(dimet'hylamino-5-methylphenyl-1 -p~iperidlinecarboxylate methyl chloride or AMO-1618, (2-chloroethyl) trimethylamnionium chloride or CCC (Cycocel), tribultyl-2,4-dichloroobenzylphosphonium chloride or Phosfon D, and N-dimethylsuccinamic acid or B-995 (B-Nine) (3, 16). Although these compounds are quite different in their chemical structure, their effect on plants is in general quite similar. The most common response is reduction of stem elongation which in extreme cases can result in almost rosette-like growth habit but which, apart from a deeper-green color and greater thickness of the leaves, is usually not associated with pronounced anomalies of development or structure, as is, for example, growsvth inhibition by high doses of .auxins or related compoun(ls. Another effect, observe(l in some plants, is suppression of the flowerinducing effect of favorable photoperiods (1, 17, 18). This effect is also selective, vegetative growth, as expressed by the rate of leaf formation, not being