Novel plant growth regulant composition comprising as an active ingredient at least one cycloalkanecarboxylic acid compound of the formula ##STR1## in which R is hydroxyl, alkoxy, aralkoxy, amino, alkylamino, dialkylamino or the radicalO.sup..crclbar. M.sup..sym. wherein M.sup..sym. is one alkali metal ion equivalent or alkaline earth metal ion equivalent, or an ammonium, alkylammonium, dialkylammonium, trialkylammonium or tetraalkylammonium ion,R.sup.1 is amino or the radical ##STR2## wherein R.sup.2 is hydrogen, alkyl or aryl, or R.sup.1 is the radical -N.sup..sym. H.sub.3 X.sup..crclbar., wherein X.sup..crclbar. is chloride, bromide or iodide, andn is 1, 2, 3, 4 or 5,in admixture with a solid or liquefied gaseous diluent or carrier or in admixture with a liquid diluent or carrier containing a surface-active agent.