結球萵苣 ''Dark Green Boston''及 ''Everglade''不同成熟溫度種子與''達豐''滲調種子，於高溫發芽時，分析胚根突出前之胚乳細胞壁分解酵素endo-β-mannanase活性、乙烯及CO2產生之情形。 ''Dark Green Boston'' 與''Everglade''30/20℃成熟種子分別於27℃及33℃下發芽率較20/10℃成熟者高43.9%、44.4%，平均發芽天數縮短。於27℃''Dark Green Boston'' 滲調種子較未滲調提高28.8%發芽率，發芽整齊度與平均發芽天數均縮短。''Everglade''滲調種子於33℃時較未滲調種子提高46.1%發芽率，增加發芽整齊度，達顯著性差異。''達豐''於33℃滲調種子發芽率較未滲調種子提高47.6%，發芽整齊度、平均發芽天數差異不顯著。 利用Gel-diffusion測定種子胚根尖端珠孔區及側邊胚乳之endo-β-mannanase活性，''Dark Green Boston''與''Everglade''之30/20℃成熟種子分別於27℃及33℃胚根突出前珠孔區酵素活性較20/10℃者高，胚根突出後側邊胚乳酵素活性高於珠孔區。''Dark Green Boston''、 ''Everglade''與''達豐''滲調種子之endo-β-mannanase活性於二發芽溫度下浸潤時，以胚根尖端珠孔區之活性較高，且滲調種子活性較未滲調者高。 ''Dark Green Boston''於二發芽溫度下，30/20℃成熟種子乙烯產生量較20/10℃者高，胚根突出前乙烯有上升趨勢，發芽後乙烯生成量逐漸減少。''Everglade''之30/20℃成熟種子所產生之乙烯於50%種子胚根突出前已達第一高峰，高溫下所產生乙烯較低溫多4.5倍，而33℃下20/10℃成熟種子發芽率為7.8%，至浸潤24小時未測得其乙烯釋出量。''Dark Green Boston''滲調種子浸潤7~8小時達50%種子胚根突出， 27℃下乙烯釋出量較20℃略高。''Everglade''與''達豐''滲調種子於20℃與33℃發芽時乙烯釋出量較未滲調種子者多，且生成變化與胚根突出時間相關。 乙烯生合成抑制劑- AVG及硫代硫酸銀(STS)處理''Dark Green Boston''種子，於20℃時發芽率顯著被抑制為52.8%及7.2%，乙烯生合成促進劑ACC及ethrel使處理發芽率達97%以上，以20mM AVG加上1mM ACC處理於20℃下種子發芽率為43%，20mM STS加上100ppm ethrel處理種子發芽率為94.5%，平均發芽天數縮短3.8天，顯著克服抑制劑作用。AVG+ACC處理之珠孔部位酵素活性較單一或合併乙烯生合成抑制劑、促進劑處理高，AVG+ACC處理種子於第12小時產生乙烯最高。 呼吸作用趨勢與乙烯生成情形相似，胚根突出前二氧化碳釋放量隨浸潤時間增加而上升，''Dark Green Boston''、''Everglade''於發芽高溫以30/20℃種子產生二氧化碳最多，三品種以滲調種子產生二氧化碳量較高，未滲調種子產生之二氧化碳量較少。''Dark Green Boston''滲調種子於20℃時產生與endo-β-mannanase相同分子量位置編號2、3、4之蛋白質，浸潤於27℃使未滲調種子產生少量編號1及3蛋白質，不同成熟溫度種子影響編號4蛋白質之產生，27℃下20/10℃成熟種子減少編號1蛋白質，而30/20℃成熟種子內則減少編號4之蛋白質。 種子經處理後於高溫下發芽率高，發芽時間早，其endo-β-mannanase酵素活性及乙烯生成變化對克服溫度逆境下種子之發芽表現成正相關。 The germination of lettuce seeds germinated at high temperature was studied. Assay the evolution of ethylene and CO2 as well as the activity of endo-β-mannanase before radicle protrusion of ̀Dark Green Boston ́ and ''Everglade'' seeds matured under two temperatures or primed treatment by polyethylene glycerol. The germination of seeds matured at 30/20℃ was higher than the seeds matured at 20/10℃. The germination of ''Dark Green Boston'' and ''Everglade''seeds matured at 30/20℃ was 97.8% and 52.2% at 27℃ or 33℃, respectively. The mean germination time of seeds matured at 30/20℃ were shortened. At 27℃, priming treatment could increase 28.8% germination percentage of ''Dark Green Boston''seeds compared to that of the non-primed seeds. The germination uniformity and the mean germination time of primed seed of ''Dark Green Boston'' were shortened. At 33℃, the germination percentage was increased 46.1% and the germination uniformity was shortened 0.4 days of ''Everglade'' primed seed. At 33℃, the germination percentage of ''Mesa 659'' primed seed was increased 47.6% compared to that of non-primed seeds. There was no significantly different on germination uniformity and mean germination time. A gel-diffusion assay was used to measure endo-β-mannanase activity during the germination of lettuce seed. At 27℃ or 33℃ before radicle protrusion, endo-β-mannanase activity at micropylar region of ''Dark Green Boston'' and ''Everglade''matured at 30/20℃ seeds were higher than those matured at 20/10℃. Three cultivars of primed seeds germinated at high or low temperature, endo-β-mannanase activity of micropylar region were higher than lateral region, and those of primed seeds were higher than non-primed seeds. The evolution of ethylene from ''Everglade'' seed matured at 30/20℃ germinated at 33℃ were 4.5 folds compared to that of seed germinated at 20℃. The time when 50% of ''Dark Green Boston'' primed germinating seed exhibit radicle protrusion were 7-8 hours after soaking. The amount of ethylene produced at 27℃ was more than that at 20℃. At 20℃and 30℃, the evolution of ethylene in ''Everglade'' and ''Mesa 659'' primed seeds were more than non-primed seeds, respectively. The germination percentage of ''Dark Green Boston'' seeds were reduced 52.8% and 7.2% by AVG and STS at 20℃, respectively. The germination was promoted by ACC and ethrel to 97%. The seed treated with 20mM AVG and 1mM ACC had 43% germination percentage at 20℃. The seeds were treated with 20mM STS and 100ppm ethrel increased the germination percentage to 94.5% and the mean germination time was shortened to 3.8 days. These treatments significantly overcome the action of inhibitors. The Endo-β-mannanase activity in micropylar region of seeds treated with AVG +ACC were more than other treatments. The ethylene production of seeds treated with AVG +ACC was the most among the treatments. The relationship between the ethylene production and an increase endo-β-mannanase activity before radicle protrusion when the seed germination at high temperature was confirmed in this study.