EFFECT OF EXOGENOUS AUXIN ON ROOT MORPHOLOGY AND SECONDARY METABOLISMIN TAGETES-PATULA HAIRY ROOT CULTURES

In this paper the effects of indole-3-acetic acid (IAA) on growth of T agetes patula hairy root cultures and secondary product formation are presented. The biosynthesis of thiophenes, sulfurous compounds with ne maticidal activity, was inhibited by IAA application, as was evident f rom a decrease of [S-35]sulfur incorporation. The inhibition only occu rred after the roots had developed numerous lateral as a result of aux in action. However, in roots cultured in the absence of IAA, there was no significant correlation between branching and thiophene accumulati on. Therefore, development of lateral roots is not a sufficient condit ion for a low capacity to synthesize thiophenes. The highest rate of t hiophene accumulation in the roots is found during the late exponentia l growth phase, when the weight increase of a root culture is at its m aximum. Hence, growth and the production of thiophenes appear to be co mpatible in T. patula hairy roots.