Studies On Characteristics Of Pollination And Fertilization In Forsythia Suspensa (Thunb.) Vahl

To identify the reasons for low yield and medicinal materials poor quality in Forsythia suspensa, both long style type and short style type Forsythia suspensa used as basic material in this paper, the pollen size, shape, surface sculpture, viability, germination rate, setting percentage , pollination and fertilization process were observed and determination by the Scanning Electron Microscope, TTC stainning, culture in vitro, cross pollination, fluorescence microscopy and paraffin section technology. The main results are showed that:Florescence is longer and concentration, which florescence is 27days for long style type Forsythia suspensa and florescence is 32 days for short style type Forsythia suspensa. Initial bloom stage and full bloom stage not encounter, but initial bloom stage and drop bloom stage encounter, initial bloom stage have 15 days encounter between two types of Forsythia suspensa. It main taking crossing pollination, but seed setting rate is very with self-pollination.Stagma have longer effective pollination period, from pre-flowering 2 days to blooming 15days all maybe seed setting and pollination seed setting rate is over 60%,belong to facultative outcrossing plant.Both pollen shape were long ellipse, the exine ornamentation were typical network sculpture; but in short style type Forsythia suspense mesh have particle and long style type Forsythia suspense.mesh have not particle. Pollen viability of short style type Forsythia suspense was obvious higher than long style type Forsythia suspense.Pollen germination optimum temperature is 25℃between two types of Forsythia suspensa.But flowering temperature is 15～20℃.There have longest germination rate and longest pollen tube between two style type pollen in Forsythia suspense with 15% sucrose + 400 mg.L-1boric acid medium, which germination rate of long style type pollen is 28.8% and germination rate of short style type pollen is 61.1%.Pollen were effect between two style type pollen in Forsythia suspense with plant growth regulator. Pollen germination and pollen tube growth was promoted with 0～25 mg.L-1 naphthylacetic acid, 300～500 mg.L-1gibberellin, 10～25 mg.L-1 indoleacetic acid, 10 mg.L-12,4-D in long style type Forsythia suspense, but only 25 mg.L-1 indoleacetic acid promote pollen germination and pollen tube growth for short style type Forsythia suspense, the other plant growth regulator inhibit pollen germination and pollen tube growth for short style type Forsythia suspen.Alitte pollen tube enter stylar canal, but growth seep slowly, stopping growing in stylar canal. Self-pollination in short style type Forsythia suspense, pollen tube growth slowly, only a little ovule fertilizationed, but placenta withered died after pollination 21 day, ovule fertilization failed. But out crossing pollination, pollen tube enter ovule in 168 hours, release sperm cell and nutrient in ovule was after pollination 18 days.Pollen life is shorter in Forsythia suspen, pollen lost viability in blooming 7 days between two style type pollen in Forsythia suspense.So we shoud mixing planting between two style type pollen in Forsythia suspense, outcrossing pollination in full bloom stage and initial bloom stage, increase yield.