Abstract: Floral syndrome and morphological variability show the adaptability to a variety of pollination modes in angiosperms.Descurainia sophia,an early spring ephemeral plant species,possesses the floral design matching with self-pollination due to the small and inconspicuous petals,but the anther-shape-like petals and persistent calyxes seem to have a certain relationship with attracting pollinators.In order to explore the relationship between floral syndromes and pollination patterns,in this study the flowering habits,floral characteristics,advertising effect of petals,mating system and so on of D.sophia,a natural population in Xinjiang,were lucubrated based on the field observation and artificial control test.The results showed that D.sophia is a facultative selfer,self-compatible with a maintained capability to outcross.On a sunny day,the flowers bloom around 10:00 o’clock and closure around 17:00,and the florescence is for 1-2 days.After blooming,pistils grow continuously and experience three stages: they are lower than stamens,as high as stamens and higher than stamens.There are pollinators of D.sophia,but their visiting frequency is extremely low,and the visiting frequency was 0.062±0.027 flower·h^-1 in 2015 and 0.01±0.005 flower·h^-1 in 2016.There was no significant difference between the control experiment by removing petals and persistent calyxes and the contrast.Both of the anther-shape-like petals and persistent calyxes have no advertising in attracting pollinators.The pollen loads on stigmas mainly derived from self-pollen in D.sophia.The self-pollen transfer occurs at the two stages when pistils are the same as height of longer stamens and shorter stamens respectively.The tiny flower size,low P/O value and anther-shape-like petals may be the result of decrease of resources allocation invested in floral show and rewards,and also show the reproductive strategies of being compatible with self-pollination pattern.

Key words: Descurainia sophia, mating system, pollination pattern, floral syndrome