The dwarfing effect of paclobutrazol and chlormequat on Bombax ceiba seedlings

Bombax ceiba is an established species in dry-hot valleys, playing an important role on the ecological stability; Bombax ceiba is an important ornamental tree plant but very tall. In order to dwarf the tall tree into pot seedlings through artificial treatment for higher commercial value, potted experiments were adopted. Pleiotrazole (PP333), chlormequat (CCC) with different concentrations and water were applied from the beginning of Bombax ceiba seedlings by root irrigation treatment. The difference between the three treatment groups was studied. The results showed that there was significant difference between the effect of two kinds of retarders by different concentrations in seedling height and basal diameter. PP333 treatment with 200 mg/L had the best dwarfing effect on high growth, followed by 250 mg/L. Under CCC treatment, 2500 mg/L had the best dwarfing effect on high growth, followed by 1500 mg/L. However, PP333 inhibited the growth of basal diameter as well as the high growth, while CCC promoting the growth of basal diameter. Therefore, it is suggested that in the dwarfing treatment of Bombax ceiba seedlings, PP333 could be used after seed germination to inhibit seedling height growth and CCC should be applied to promote the basal diameter development of Bombax ceibas 90 days later.