Research On Characteristics Of Jackfruit Pollination And Embryo Development

Jackfruit (Artocarpus heterophyllus Lam.) is one of the most famous tropical fruit inthe world, undstanding of processes of pollination and embryo development is basis of itscultivation and breeding. In this thesis, phenological phase of flowering, pollen viabilityand its performance in storage as well as fertilization and embryo development werestudied, resutls were as follows:1、Flowering phenology of3germplasm, GHsj12S17、GHsj12S28and GHsj12S45,were investigated. Results indicated that, female influorescence of jackfruit has a longflowering period, which ranged from7to39days and mainly in February and March.GHsj12S17has the longest flowering period among germplasm investigated, with aflowering period of39days.2、The medium for germination of jackfruit pollen was optimized using orthogonalexperimental design, then the pollen germination ability of12germplasm wereinvestigated and storage characteristics of3germplasm of them were analyzed. Resultsshowed that, sucrose and boric acid significantly influenced the rate of pollen germination,with the medium concentration of sucrose, boric acid and calcium chloride studied werebest for the germination of jackfruit pollen, and the optimal medium was100g/L sucrose+0.12g/L boric acid+0.10g/L calcium chloride; pollen germination rates of12jackfruitgermplasm were5.55-65.51%, and significant differences existed among differentgermplasm; pollen of jackfruit was best to be stored under conditions of dry and lowtemperature, because the germination rate would decreased largely after1d at roomtemperature and4d at4℃,and after storage at4℃,-20℃and-80℃for22d, rates ofpollen germination were5.86-8.09％,3.63-4.68％and5.77-6.54％respectively, anddifferences were detected among different germplasm. In conclusion, pollen of jackfruitwas best to be collected in the time of need or stored at4℃for1-4d and-80℃for longterm, and differences in pollen viability among different germplasm should be put intoconsideration when use it.3、Rates of fruit setting of4germplasm under conditions of natural pollination,artificial self-pollination and cross-pollination were investigated. Results showed that, thefruit setting rate under natural pollination of four germplasm ranged from32.26%to88.89%, the fruit setting rate under self-pollination of four germplasm ranged from25%to50%, the fruit-setting rate under cross pollination of four germplasm ranged from0%and 100%.4、Pollens germinated and formed pollentube around6h after pollination; pollen tubeentered into style12h after pollination; pollen tube entered into the ovary24h afterpollination. The embryo sac development in jackfruit was polygonum-type. After doublefertilization, endosperm dormanted for a short time and then begined to divide at the ninthday after post-full blossom, which was earlier than the zygote. Embryo finally maturedthrough developments of globular embryo, heart-shaped embryo and cotyledon embryo,which was at16th,18th,21th day after post-full blossom, respectively. Fertilized polarnucleus developed into cellular endosperm.5. Embryo abortion occured at all stages of embryo development. Embryo abortionresulted from, empty embryo sac, embryo sac abortion, ovules abortion and unfertilizedembryo.