Abstract: [Objective] ‘Yuluxiangli’ forms wizened buds in some pear orchards. In this study, the dynamic changes of the mineral elements in normal flower buds in short shoot and adjacent blades were measured to investigate the effects of mineral elements on flower bud differentiation, and further explore the formation mechanism of ‘wizened buds’ in pear. This study aims at providing the theory for preventing wizened buds formation.[Method] The Yuluxiangli short branches flower buds with normal development and the adjacent leaves, collected in Shanxi Taigu and Hebei Weixian, were used as the experimental materials. The flower bud development was observed with paraffin method and section. The K, Ca, Mg, Fe, Mn and Zn contents during flower bud differentiation were determined with flame atom absorption method.[Result] 1) The time of stopped growth of annual branches in wizened bud pear orchard was later and the growth amount were significantly more than that in normal pear orchards. This result indicated that the delay stop growth and excessive growth of branches affected the flower bud development. 2) The bud morphological differentiation stage of ‘Yuluxiangli’ began from early June to mid-June. After flower bud differentiation phase finished (in middle of July), buds appeared browning and death, which was observed under the microscope. The result suggested that wizened buds in pear would happen in mid July during the sepal differentiation phase.3) The contents of mineral elements were obviously different in wizened bud pear orchard and normal pear orchards. From June 15 to August 15, contents of K, Ca, Mg, Mn and Zn in the buds in the wizened bud pear orchard were lower than that in normal pear orchards; Fe content in the buds in the wizened bud pear orchard was higher than that in normal pear orchards; Ca and Mg contents in the leaves in the wizened bud pear orchard were higher than that in normal pear orchards; Mn and Zn contents in the leaves in the wizened bud pear orchard were lower than that in normal pear orchards; K and Fe content of the leaves were no significant difference in different pear orchards.[Conclusion] In normal pear orchard in Weixian the cultivation measures, such as water-controlling, fertilizer-controlling, branch-drooping, girdling, plant growth retardants, were applied besides the regular management, which effectively inhibited the vegetative growth, returned to normal mineral nutrition metabolism and significantly reduced formation of wizened buds.

Key words: pear, wizened bud, mineral elements, flower bud differentiation