Abstract: The new compounds of the formula I ##STR1## in which R denotes substituted phenyl,X denotes a radical of the formula --SH, ##STR2## or hydrogen, Y denotes a radical of the formula ##STR3## and the bisulfite adducts, acetals, ketals, thioacetals or thioketals derived from ##STR4## Z denotes O, S or N--R.sup.6 ; m denotes 0, 1 or 2; n denotes 0, 1, 2, 3 or 4 and p denotes 2 or 3,and the salts and quaternization products which are acceptable for agricultural purposes have advantageous plant growth-regulating actions. Processes for the preparation thereof are also described.

Abstract: The salts of 1-phenylimidazole-5-carboxylic acids substituted in the phenyl ring, of the general formula (I) ##STR1## exhibit a good plant growth-regulating activity. In the general formula the symbols have the following meaning:Y is an ammonium ion substituted up to fourfold by (substituted) alkyl, (substituted) alkenyl, alkynyl, (substituted) cycloalkyl, cycloalkenyl, and (substituted) phenyl, wherein the charged N may be part of a heterocyclic radial (NH.sub.4.sup.+ is excepted); phosphonium ion substituted fourfold by alkyl, (substituted) phenyl or (substituted) benzyl; sulfonium- or sulfoxonium ion substituted threefold by alkyl, (substituted) phenyl or (substituted) benzyl; the guanidinium ion or an O-alkylisourea cation;R.sup.1, R.sup.2 independently of each other are alkyl;R.sup.3 is alkyl, alkoxy or halogen; andn is 0, 1, 2 or 3.