種子處理對人工老化萵苣種子抗氧化作用之影響

Effects of Seed Treatments on the Antioxidation of Accelerated Aged Lettuce Seeds

‘達豐’結球萵苣種子經2天40℃、100%RH老化處理後，老化處理後之種子於25℃有68.9%發芽率，30℃有38.5%發芽率，35℃有0%發芽率。老化種子經-1.2Mpa PEG滲調於30℃有71%發芽率，於35℃有33%發芽率；10 mM GA3+ 100µM BA + 10 ppm Ethrel處理於30℃有70%發芽率，在35℃下有32%發芽率。經老化處理及高溫浸潤下，會導致種子內總過氧化物、脂質過氧化物及oxidized glutathione（GSSG）之含量增加，降低20% superoxide dismutase（SOD）、catalase（CAT），35% peroxidase（POD）、10% glutathione-S-transferase（GST）之過氧化物清除酵素活性及GSH（reduced glutathione）、total glutathione含量。經滲調及植物生長調節劑處理後，種子在35℃下總過氧化物、脂質過氧化物及GSSG之含量減少，增加SOD、CAT、POD、GST、glutathione reductase活性及GSH、total glutathione含量。老化或種子於35℃下浸潤，會降低種子內蛋白質之含量，其含量可以滲調及植物生長調節劑處理增加之。 The germination rate of ''MESA659'' lettuce seeds that were aged for 2 days was 68.9% at 25℃, 38.5% at 30℃, and 0% at 35℃. Priming with -1.2 Mpa PEG for four days increased the germination of aged seeds to 71% at 30℃ and 33% at 35℃. 10 mM GA3 + 100 µM BA + 10 ppm Ethrel increased germination to 70% at 30℃ and 32% at 35℃. In aged seeds germinating at 25℃ and non-aged seeds germinating at 35℃, total peroxide, malondialdehyde and oxidized glutathione (GSSG) increased, as the activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione-S-transferase (GST), and the amount of reduced glutathione (GSH) and total glutathione decreased. Priming and hormone treatments reduced total peroxide, malondialdehyde and GSSG. On the other hand, these treatments increased the activity of SOD, CAT, POD, glutathione reductase (GR) and GST as well as the amount of GSH and total glutathione in seeds imbibed at a high temperature. Aged seeds or seeds imbibed at 35℃ had lower soluble protein content. However, priming and hormone treatments increased the soluble protein content and counteracted the effects of high temperature and aging.