：四季秋海棠於臺灣夏季栽培常因高溫而生育不良。由於外加水楊酸可提高有些其他植物對高溫逆境的耐性及生育表現，本研究探討水楊酸對高溫下四季秋海棠葉綠素螢光與生長之影響。首先以100 μΜ 水楊酸葉面噴施或介質灌注處理‘Super Olympia White’和‘Super Olympia Pink’品種盆栽植株，處理後經高溫(日/夜溫35/30℃) 14 天，兩品種處理組植株的Fv/Fm 及Fm 值均高於對照組；其中‘Super Olympia White’灌注處理組的葉綠素螢光值高於葉面噴施處理組；而‘Super Olympia Pink’灌注處理組則與葉面噴施處理組相似。其次探討水楊酸適用濃度，以0、25、100 或400 μΜ 水楊酸灌注‘Super Olympia Red’盆栽植株，處理後移入高溫(35/30℃)。藥劑處理後初期(7小時內)，100 及400 μM兩組處理，其F0明顯較對照組低，而Fv/Fm 則明顯較對照組高；移入高溫後觀察日變化，水楊酸各處理F0 多較對照組為低，Fm 及Fv/Fm 多較對照組為高，其中尤以濃度100 μM 處理表現最為明顯。另再針對水楊酸施用方式及濃度進行探討，分別以0、100 或400 μΜ 水楊酸噴施或灌注‘Super Olympia Pink’盆栽植株。試驗前期400 μΜ 灌注者於處理第2 天後的F0 明顯低於對照組，Fv/Fm 明顯高於對照組；試驗末期（處理後第12 天起）100 μΜ 處理者Fm 較各處理者高。又試驗結束時植株外觀性狀表現也與葉綠素螢光表現結果相同，以100 及400 μΜ 水楊酸處理者較健壯。經多次試驗結果證實水楊酸在適當濃度及施用方式下，的確具有提高四季秋海棠高溫耐熱性之潛能；其中以100 μΜ 水楊酸灌注處理具有較佳的處理效果。

Wax begonia plants often suffer from high temperature stress during summer hot seasons in Taiwan. Since salicylic acid (SA) had been known to enhance heat tolerance in some other plants, we investigated the effect of exogenous SA applications on chlorophyll fluorescence and growth of ‘Super Olympia’ wax begonias (Begonia ×semperflorens-cultorum Hort.) under 35/30℃ heat stress conditions. The values of Fv/Fm and Fm of the plants treated with 100 μΜ SA, either as a foliar spray or medium drench, were higher than those of the controls. The values of Fv/Fm and Fm of plants with medium drench treatment were higher than those of foliar spray treatment in ‘Super Olympia White’; but the values for the two treatments were equal in ‘Super Olympia Pink’. Three concentrations (25, 100 or 400 μΜ) of SA were applied to ‘Super Olympia Red’ plants in 12-cm diameter pots as a medium drench of 50 mL and then transferred to high temperature environment (35/30℃ for 16 d). All treated plants had higher Fv/Fm values than the controls. The 25 and 100 μΜ treatments resulted in higher Fm as well as lower F0 than the controls. Plants treated with 100 μΜ SA by medium drench had the lowest F0, higher Fm, and Fv/Fm values. Applications of SA either as a foliar spray or medium drench also increased the plant height, number of branches, and the SPAD-502 value of wax begonia.