Floral Evocation and Differentiation Period in Japanese Pepper (Zanthoxylum piperitum (L.) DC. f. inerme Makino) Tree

Abstract

Floral evocation and differentiation in Zanthoxylum piperitum (L.) DC. f. inerme Makino (Budousanshou) Japanese pepper were investigated to obtain basic data for developing cultural techniques that will increase the number of fruit set. Panicle formation occurring at the tip of a new shoot after grafting was investigated to evaluate floral evocation, and microscopic observation of apical and lateral buds on spring shoots was done to determine floral differentiation from June through March. Floral evocation was completed from late June through early July at Shimizu-Cho in Wakayama Prefecture in 2004. Floral differentiation was observed in July and August on the same tree. The number of small flowers in a panicle remained constant from August to February but increased rapidly in March before bud sprouting occurred.