Effects of paclobutrazol on vegetative and reproductive growth of lemon.

【Objective】The effects of paclobutrazol on the vegetative and reproductive growth of lemon were studied to provide theoretical and practical references for inhibiting new shoot, promoting flowering and improving yield. 【Method】PP333with 400, 600, 800, 1000 and 1200 mg/kg was sprayed to lemon trees for statistics of new shoot number and mean bud number per branch,and then determining transverse diameter, longitudinal diameter, physical properties, and yield in different treatments. 【Result 】The number of new shoot was inhibited significantly with different PP333concentrations compared with the control. PP333caused marked increase in the flower bud per branch, and flowers and fruits per branch in the next year, and it could also lengthen blooming period significantly. Compared to the control, the number of flower bud and flower per branch were the most when the PP333concentration was 800 mg/kg with the increase rate of 53.34% and183%,respectively. The treatments of 800 and 600 mg/kg PP333caused increase of the longitudinal diameter of autumnflowering lemon and spring-flowering lemon in slow growing period. PP333had no influence on physical properties and transverse diameter during the whole growth period, while it could significantly increase the yield per plant and hectare yield. The yield per plant and hectare yield increased the most when the PP333concentration was 800 mg/kg with the increase rate of 41.07% and 41.63%,respectively. 【Conclusion】PP333at the proper concentration could inhibit the growth of vegetative, and promote the growth of reproductive with concentration of 800 mg/kg being the optimal.