本研究探討植物生長調節劑40%勃激素A3 (gibberellic acid)水溶性粒劑，在台灣地區不同氣候環境下施用，對促進蓮霧果實生長及植株藥害之評估，以提供安全有效之使用方法，作為田間實際應用之參考。試驗分別在屏東縣南州鄉三處蓮霧園內進行。於花蕾形成初期、豆粒期及謝花幼果期，分別噴施80,000 倍及60,000倍之40%勃激素A3 水溶性粒劑，並於果實成熟後採樣調查藥效及藥害發生情形。測試藥劑以60,000 倍及80,000 倍噴施後，蓮霧果梗長度由對照處理之6.87±0.25 cm顯著增加至7.83±0.06 cm 及8.30±0.61 cm，也較對照藥劑10%勃激素A3 水溶性片劑20,000 倍處理之7.57±0.72 cm 為長，同時果形也有加長之趨勢。高劑量(60,000倍)處理對單果果重也有明顯提升之效果。此外測試藥劑具有提高糖度及降低酸度之作用，其中80,000 倍處理之果實糖度明顯增加，但劑量間無顯著差異。蓮霧果皮色澤反應結果顯示，測試藥劑較對照處理有明顯加深果皮著色及轉紅現象。各試驗區藥劑處理後，植株均未出現形態異常之藥害現象。綜合試驗結果，以40%勃激素A3 水溶性粒劑60,000 倍噴施蓮霧植株，對果梗伸長、果重增加及果形改善均有明顯促進效果，且對果實甜度與果皮色澤亦有提升作用。

The wax apple (Syzygium samarangense Merr. et Perry) is a tropical fruit crop thathas been cultivated very commonly in southern Taiwan. The experiments were conductedby Fengshan Tropical Horticultural Experiment Branch and Kaohsiung DistrictAgricultural Improvement Station to evaluate the effect of gibberellic acid (GA3) 40%SG (water soluble granule) on fruit characteristics and quality in wax apple during2009-2010. GA3 40% SG was sprayed with dilution rate of 1ml/80L and 1ml/60L ofwater at different growth stages of early bud, middle bud and young fruit in three waxapple orchards of Nanjou. GA3 40% SG applications at the tested rates caused theelongation of fruit stalk to 7.83±0.06 cm and 8.30±0.61 cm from 6.87±0.25 cm incontrol. It was also found that fruit shape became slightly elongated after treated withtested chemicals. GA3 40% SG sprayed at higher concentration (1ml/60L of water) wasmore effective in increasing fruit weigh. These treatments also improved the fruitquality with higher sugar content and lower acidity. After GA3 40% SG application, skincolor of wax apple trended to deep red in treated fruit. The application of GA3 40%SG sprayed with dilution rate of 1ml/60L of water was, therefore, considered to improvefruit quality without crop injury under this experiment conditions.