Flower structure and biological characteristics of flowering and pollination in Iris japonica Thunb.

A field investigation was conducted on the floral syndrome and pollination characteristics of Iris japonica Thunb.in artificial populations by continuous observation,out-crossing index,pollen-ovule ratio and fruit-set rat.The main results are as follows:Under artificial culture conditions,the population come into bloom from Febrary to April and the flowering span among populations is 62 days.The flowering span for a plant is 9-28 days.The life span of one single flower was approximately 36-48 hours.The stamen was close to the lateral side of the petaloid style and 0.32 cm shorter than the style,and the relative position between the stamen and style was always unchanged in the whole flowering process.The out-crossing index was 4,P/O was about 275.68,combined with the result of the bagging and artificial pollination experiment,the breeding system of those species was given priority to out-crossing,part self-compatibility,insects pollinator-dependent.The special floral structure may be the reasons that those species have a low setting percentage.