乙烯與結球萵苣種子發芽之關係

Relationship between Ethylene and Germination of Lettuce Seeds

‘Dark Green Boston’、‘Everglade’及‘達豐’萵苣種子經滲調處理於二溫度下發芽，分析乙烯產生量及endo-β-mannanase活性與種子發芽之關係。經滲調種子浸潤7～12小時達50%種子胚根突出，未滲調種子者則於15～19小時，滲調種子於27℃或33℃發芽時下乙烯釋出量及二氧化碳量較20℃者多。乙烯生合成抑制劑-AVG及硫代硫酸銀（STS）處理‘Dark Green Boston’萵苣種子，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使發芽率達97%以上，以20 mM AVG加上1 mM ACC處理於20℃下種子發芽率為95%，20 mM 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。‘Dark Green Boston’種子於27℃下STS處理於加上Ethrel處理增加編號4蛋白質或AVG處理於加上ACC處理增加編號3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。 Seeds of ‘Dark Green Boston’, ‘Everglade’ and ‘Mesa 659’ were primed and germinated at two temperatures. The purpose of this study is to examine relationship between endo-β-mannanase activity and seed germination 50% of these three varieties of primed lettuce seeds exhibited radicle protrusion after 7-12 hours of soaking, while it took 15-19 hours for unprimed seeds to achieve this. The amount of ethylene or CO2 produced from these three varieties of seeds at 27℃ or 33℃ was more than that at 20℃. The germination percentage of ‘Dark Green Boston’ seeds was reduced to 52.8% and 7.2% by AVG and STS at 20℃, respectively. The germination rate was enhanced by ACC and ethrel to 97%. The seeds treated with 20 mM AVG and 1mM ACC had a germination rate of 95% at 20℃. The treatment of seeds with 20 mM STS and 100 ppm ethrel increased the germination percentage to 94.5% and shortened the mean number of days to germination to 3.8 days. These treatments significantly overcame the action of inhibitors. Both amount of ethylene and the activity of endo-β-mannanase in micropylar regions of seeds treated with AVG + ACC were higher than those treated in other ways. Protein No.4 increased when ‘Dark Green Boston’ seeds were imbibed at 27℃ and treated with STS + Ethrel, while protein No.3 increased in seeds treated with AVG +ACC. The relationship between ethylene production and endo-β-mannanase activity before radicle protrusion when seeds germinated at a high temperature was confirmed in this study.