Relationship Between Floral Sex Differentiation and Endogenous Polyamines in Cucumber (Cucumis sativus L.)
CHEN Xue-Hao ZENG Guang-Wen(Department of Horticulture, Zhejiang University, Hangzhou 310029)
Changes in the endogenous polyamine(PAs) contents during floral sex differentiation and sex reversal were studied in flowers of cucumber. The results showed that endogenous putrescine(Put) content was higher in male flower than in the female during floral sex differentiation. Remarkable increase in put content was accompanied with pollen grain formation and development. Endogenous cadavarine(Cad) content in female flower from megaspore mother cell stage to female flower maturation was higher than those in male flowers from microspore mother cell stage to maturation. High level of endogenous Cad content was favorable to female flower development. While high level of endogenous PAs, spermine(Spm) and spermidine(Spd) contents were favorable to megaspore mother cell development of female flower, it seems that Put and Spd contents increased and decreased,respectively,as the formation of both microspore and megaspore tetrad and continuous division of megaspore nucleus(Fig.1). Endogenous Spd and Put contents in the apex tissue of gynoecious cucumber decreased and increased, respectively, after application of silver nitrate, which caused male differentiation(Fig.2). They, however, increased and decreased,respectively, in the apex tissue of androecious cucumber after application of ethrel, which caused female differentiation(Fig.3).