木虌果花粉體外發芽培養基配方與花粉懸浮液應用初探

Preliminary Study on Medium Composition of In Vitro Pollen Germination and Pollen Suspension Application of Momordica cochinchinensis (Lour.) Spreng.

臺灣栽培之木虌果（Momordica cochinchinensis （Lour.） Spreng.）因自然環境缺乏授 粉昆蟲，常導致著果率低及果形不正，需要人工授粉協助提高產量及品質。人工授粉時， 選用之花粉及其活力之判別為人工授粉成功之重要基礎。本研究使用臺灣原生種木虌果 之優良選系為調查材料，探討花粉成熟度及花粉貯藏對花粉活力之影響，測試木虌果花粉 體外發芽液體培養基之最適成分組成，並將其應用於人工授粉之花粉懸浮液，以田間著果 率初步評估其發展可行性。分別收集木虌果雄花綻放前一日（花藥未開裂）及雄花綻放當日 （花藥開裂）之花粉進行田間授粉，並將部分花粉置於 4°C 貯藏 1 至 3 日後取出授粉，同時 調查其體外花粉發芽率及田間著果率。結果顯示，於花藥開裂時收集之花粉，其體外發芽 率及田間著果率皆顯著高於取自花藥未開裂之花粉，且花藥開裂之花粉經 4°C 貯藏 1 日 後，仍可維持較高的體外花粉發芽率與田間著果率，其顯著高於花藥未開裂之花粉表現。 為增進木虌果花粉活力之判別，以 BK 培養基配方為基礎，分別測試木虌果花粉發芽之蔗 糖、硼酸、四水合硝酸鈣最適配方濃度（Gac BK-modified），結果顯示以 150 g·L-1 蔗糖、 300 mg·L-1 硼酸與 500 mg·L-1 四水合硝酸鈣，及硫酸鎂 200 mg·L-1、硝酸鉀 100 mg·L-1 成 分組成時，木虌果花粉體外發芽有最佳表現。進一步將新鮮與經低溫貯藏的花藥開裂花 粉，分別使用 Gac BK-modified 溶劑、150 g·L-1蔗糖溶液、純水配製花粉懸浮液，進行人 工授粉後並比較其田間著果率，結果顯示以 Gac BK-modified 溶劑配方在三者中有較高的 著果率，且低溫貯藏 1 日的花粉仍可維持著果率，但相比於直接以純花粉授粉之對照組 仍顯著較低。本研究提出之木虌果花粉體外發芽液體培養基最適成分組成，除可應用於評 估花粉活力，亦為後續發展木虌果人工授粉技術之有利基礎。

The spiny bitter gourd or gac (Momordica cochinchinensis (Lour.) Spreng.) cultivated in Taiwan lacks the pollination insects which results in low fruit yield and abnormal fruit shape. Under this circumstance, artificial pollination is required to help solve these issues and discriminating the pollen viability is a vital step to the artificial pollination. In this study, the indigenous gac of Taiwan was used as the materials to find out the effects of the pollen collections and storage on the pollen viabilities. The suitable formula of liquid medium for pollen tube in vitro germination of gac wos also examined. The preliminary test according to fruit-setting ratio for the application of gac liquid culture medium in the artificially pollination was estimated. We collected the pollen from the male blooming flower with dehiscent anthers (FB pollen) and the male flower of one day before anthesis (FOB pollen), respectively. Theses pollens were examined for their pollen viability in vitro test and artificial pollination. Some of the pollens were stored at 4°C for 1, 2, 3 days and investigated for their pollen viability and fruit-setting rate after artificial pollinated in the field. The results showed the pollen viability and fruit-setting rate of FB pollen were higher than FOB pollen. Even FB pollens were stored for 1 day at low temperature, it had a better performance than FOB pollen. To improve the examination of gac pollen viability, we took BK medium as the basis and figured out the suitable concentrations of sucrose, boric acid, and calcium nitrate tetrahydrate for the pollen germination in vitro of gac. The best formula of liquid culture medium for in vitro pollen germination of gac (Gac BK-modified) was 150 g·L-1 sucrose, 300 mg·L-1 boric acid, 500 mg·L-1 calcium nitrate tetrahydrate, with 200 mg·L-1 magnesium sulfate and 100 mg·L-1 potassium nitrate. We used Gac BK-modified, 150 g·L-1 sucrose solution, and water as the solvents of pollen suspension, respectively, with fresh and storage FB pollen. The fruit-setting rate after artificial pollination showed that there was more fruit set in the Gac BK-modified solution with fresh FB pollen among the treatments. The Gac BK-modified solution would maintain the fruitsetting rate of 1-day-storage FB pollen as the fresh pollen. Our study demonstrated that the fresh pollen was more suitable for the artificial pollination, and the best formula for in vitro pollen germination of gac pollen. The preliminary evaluation of the pollen suspension application with Gac BK-modified solution is useful for developing the artificial pollination in gac cultivation in Taiwan.