| Summary: | 碩士 === 國立嘉義大學 === 農學研究所 === 91 === The results of pollen germination and growth of Ixora showed as follows：The effects of temperature, medium components, sucrose concentration, pH value and proline concentration on pollen germination and growth in vitro varied with species and cultivars. The higher temperature, the higher pollen germination. The pollen germination both Ixora williamsii‘Sunkist’ and Ixora williamsii‘Dwarf Yellow’cultured at 30℃ and 35℃ were 30.29% and 29.13%,24.95% and 35.49% respectively. No pollen or a few pollens germinated among all of species and cultivars grown at 15℃. The best medium components for pollen germination of Ixora williamsii‘Dwarf Yellow’ and Ixora williamsii‘Sunkist’were boric acid 100mg/L, sucrose 10-20%, pH adjusted to pH5-6. Additional proline at 5.0-7.5mg/mL supplement in the medium resulted increase in the pollen germination for Ixora williamsii‘Sunkist’. No pollen germination in Ixora duffii‘Super King’was found whatever medium formula and temperature regime.
The results of pollen germination and growth in vivo showed as follows：Pollen could germinated on the stigma and penetrated into the style in self- and cross-pollinated between Ixora williamsii‘Dwarf Yellow’ and Ixora williamsii‘Sunkist’grown at greenhouse or 25℃ day/night temperature incubator . However, pollen tubes were stunted at upper 1/3 position of style after 48 hours pollination. Pollen tubes could extend to the basal style in self-pollinated Ixora williamsii‘Dwarf Yellow’ and cross-pollinated Ixora williamsii‘Sunkist’× Ixora williamsii‘Dwarf Yellow’ grown at 30℃ after 48 hours pollination. However, only a few pollen tubes reached the basal style. Although most pollen tubes extended to the basal style in Ixora williamsii‘Sunkist’× Ixora williamsii‘Dwarf Yellow’, pollen tube growth stunted and showed reverse growth at upper 1/3 position length of style in self-pollinated Ixora williamsii‘Sunkist’. Pollen germinated well on the stigma, but only a few tiny pollen tubes showed in style of Ixora chinensis × Ixora williamsii‘Sunkist’. Pollen germinated well on the stigma too, however, pollen tube growth stunted at upper 2/3 position of style. No pollen germinated on the stigma which Ixora chinensis or Ixora duffii‘Super King’ was used as a male parent.
The inhibition site of pollen tube growth located in the style, therefore, it is proposed that Ixora appeared the gametophytic incompatibility. Ixora chinensis showed low fertile and Ixora duffii‘Super King’ showed male sterility, therefore, no fruit set was found which Ixora chinensis or Ixora duffii‘Super King’ were used as male parent. The rate of fruit set and seed germination for Ixora williamsii‘Sunkist’× Ixora williamsii ‘Dwarf Yellow’ were 48.0% and 13.64% respectively.
Paclobutrazol at 100、150、200、250 mg/L drenching treatments showed significantly reducing in the plant height, promoting flowering, increasing in leaf chlorophyll content. The recommended paclobutrazol concentrations for height control of Ixora duffii‘Super King’and Ixora × westii range from 100-200 mg/L and 100-150 mg/L respectively.
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