Effects of plant growth regulators on Tagetes erecta L.seedling growth

Plug seedlings of marigold(Tagetes erecta L.) were treated through foliage spraying with different concentrations of plant growth regulators(PGR)—daminozide(B₉),chlormequat(CCC),and paclobutrazol(PP₃₃₃).The study shows that the optimal concentrations of B₉,CCC and PP₃₃₃ for marigold seedling growth regulation are 2500mg/kg,0.3%,and 60mg/kg and the effective and safe concentration ranks of the three PGRs are 1000～2500mg/kg,0.1%～0.3% and 10～60mg/kg,respectively.Among the three optimal alternatives,60mg/kg PP₃₃₃proves best with lowest cost followed by 0.3% CCC.When CCC concentration gets beyond 1.0%,plant phytotoxicity occurs.