| Abstract: | Lilium davidii var. unicolor(Lanzhou lily) is an important economic crop in the northwest cold and arid regions of China.Effective regulation of tiller-bulb development and plant growth is the key to improving yield and quality of the lily. This study attempted to evaluate the effect of gibberellic acid(GA_3) on tiller-bulb development and plant growth of Lanzhou lily by applying GA_3 at various concentrations(0 mg/L, 10 mg/L, 30 mg/L, 60 mg/L, and 100 mg/L) before planting and in the seedling period. Results showed that the 60-mg/L GA_3 application had an inhibiting effect on tiller-bulb formation and increased the ratios of single and double bulbs but decreased the ratios of bulbs with three or more tiller bulbs, as compared to the control(CK) and other GA_3 treatments. The difference in flower number did not reach significant levels among the treatments. The tillering-related endogenous hormones IAA(indole-3-acetic acid) and Z(zeatin) content decreased, while IAA/Z increased with the 60-mg/L GA_3 treatment during tiller initiation. And also, the shoot-bulb number and total daughter-bulb number decreased significantly with the 60-mg/L GA_3 treatment. Furthermore, the 10-mg/L GA_3 application promoted growth of Lanzhou lily significantly and resulted in an increase in plant height; bulb diameter; bulb circumference; and biomass of shoots, bulbs, fibrous roots, and the whole plant. Therefore, GA_3 application is promising as a new regulation method for inhibiting tiller-bulb development and promoting bulb growth in Lanzhou lily production. |
