Nitrogen, phosphorus and potassium fertilization promotes Zanthoxylum armatum ‘Hanyuan Putao Qingjiao’ fl ower bud diff erentiation in Sichuan, China

Chinese prickly ash is an ecologically and economically important tree species. In southwestern China, its yield is low dueto severe fruit and fl ower drop related to the relatively low nutrient status of shoots and/or fl owers caused by a lack of nutrientsupply. Therefore, studies on fl ower bud diff erentiation are of great importance to improve the yield of Chinese pricklyash. An orthogonal experimental design was used to study the eff ects of N (urea, 97.8, 195.7 and 391.3 g/individual), P(superphosphate, 150, 300 and 600 g/individual) and K (potassium sulphate, 83.3, 166.7 and 333.3 g/individual) treatmentson fl ower bud diff erentiation in 3-year-old Zanthoxylum armatum ‘Hanyuan Putao Qingjiao’ trees. The results showed thatN, P and K fertilizer application signifi cantly increased the fl ower bud diff erentiation rate, branch diameter and number, thesoluble sugar content, the soluble protein content, the C/N ratio, the ABA content and the ABA/IAA ratio but decreasedthe GA content and IAA content in Chinese prickly ash. The fl ower bud diff erentiation rate was positively related to thesoluble sugar content, soluble protein content, C/N ratio and ABA/IAA ratio ( p < 0.05) but negatively related to GA andIAA ( p < 0.05). A higher P content increased the accumulation of nutrients and ABA in the buds, thereby promoting thefl ower bud diff erentiation in Z. armatum ‘Hanyuan Putao Qingjiao’. From these results, the fl ower bud diff erentiation in Z. armatum ‘Hanyuan Putao Qingjiao’ requires appropriate N, P and K fertilizer ratios and amounts. Treatment 12 (N 2 P 3 K 1 )signifi cantly improved the absorption of nutrients in the buds and promoted the diff erentiation of fl ower buds. KCI Citation Count: 0