罗甸麻疯树开花习性及花的时空分布特点

Flowering behavior and spatial-temporal distribution characteristics of Jatropha curcas in Luodian

全面系统地了解贵州麻疯树Jatropha curcas开花生物学习性,以期为进一步的调控麻疯树雌雄花比例,提高麻疯树产量提供依据。对罗甸县麻疯树开花习性及花分布情况进行了连续的观察及统计分析,结果表明：麻疯树花芽为多次分化型,1 a中多次抽枝,枝顶多次分化出花芽。麻疯树在罗甸一般从5月初开始出现花序,到9月,陆续有植株开花,1 a中一般出现2次开花高峰期,营养生长和生殖生长呈现交替生长动态;麻疯树新梢萌动是进入花芽生理分化期的重要标志;二歧聚伞花序生于当年生新枝枝顶,花序数量、花下叶片数量、每个花序上小花数量以及每花序上雌花数量在树体的东西南北4个方位及上中下位置的分布均没有显著差异;花序从露出到花序上小花全部开放约需40~50 d。单花花期一般为2~5 d。每个花序上平均有小花134个,雌花平均4个,雌雄比平均1∶33;雌花在花序上的分布与花序分枝的位置极显著相关,69%的雌花分布于花序各级分枝的第1次二歧分叉处及顶花位置,其中花序第1分枝的第1次二歧分叉处（1-1）和顶花位置（D）占48%。在花序不同位置,随着雌花数量的增加,坐果数随之增加,而坐果率降低。

To have a grasp of the overall situation of flowering characteristics of Jatropha curcas,which would provide basis for the further flower control experiment and produce higher yield of Jatropha curcas,continuous observation and statistical analysis on flowering behavior and spatial-temporal distribution characteristics of Jatropha curcas were carried out in Luodian.The results indicated that： Jatropha curcas can form flower bud many times in one year.It shoots out twigs more than once on which flower buds begin to take shape.At Luodian,Jatropha curcas is in bloom from May to September,during which there are two high tides of blossom generally and are characterized by vegetative stage and ripening stage.Vegetative Buds Germination is a main sign of Jatropha curcas entering critical period of bud physiological differentiation stage.Dichasial inflorescence grows on top of new branches.There was no significant difference in amount of inflorescence,leaf beneath the inflorescence,small flower of a inflorescence and female flower in a inflorescence in all directions： north,south,east and west,and in the upper,middle,lower of the tree.It takes about 40-50 days from inflorescences emerge to the entire small flowers blossom.A small flower is flowering for 2-5 days.One inflorescence has an average of 134 small flowers which contain 4 female flowers.Female-male ratio is 1 ∶ 33.There was great significant correlation between the distribution of female and the location of inflorescence branch.69% females grow on the terminal of different level branchs in inflorescence,including 48% female growing on the first bifurcation of the primary rachis branch and the terminal of inflorescence.At different bifurcation in an inflorescence,the number of fruit increased with that of the female flowers,as against the percentage of set fruit decreased.