氮素濃度對三種香蜂草生長、精油產量及成分之影響

Effect of Nitrogen Concentration on Growth, Yield and Essential Oil Composition of Melissa officinalis, M. officinalis 'Quedlingburger' and M. officinalis 'Citronella'

三種香蜂草M. officinalis、M. officinalis‘Quedlingburger’及M. officinalis‘Citronella’盆栽，連續八週分別以七種氮素濃度之營養液（0 mM、4 mM、8 mM、12 mM、16 mM、20 mM、24 mM）澆灌，每週兩次，每次300 mL。處理後植株之枝條數及葉片數，皆隨氮肥濃度增加而增加。以枝條數而言，M. officinalis以20 mM處理最多，M. officinalis‘Quedlingburger’及M. officinalis‘Citronella’則以24 mM處理最多。葉片數在M. officinalis以16 mM處理最多，M. officinalis‘Quedlingburger’及M. officinalis‘Citronella’則以24 mM處理最多。三種香蜂草之地上部鮮重皆以24 mM處理最重。乾重在Melissa officinalis以20 mM處理最重，M. officinalis‘Quedlingburger’及M. officinalis‘Citronella’則以24 mM處理最重。每單位鮮重精油產量在M. officinalis及M. officinalis‘Citronella’以16 mM處理最多，M. officinalis‘Quedlingburger’則以8 mM處理最多。每單位乾重精油產量在，M.officinalis及M. officinalis‘Quedlingburger’以24 mM處理最多，M. officinalis‘Citronella’則以16 mM處理最多。利用固相微萃取（Solid Phase Microextration, SPME）萃取各處理組精油的揮發性香氣後，以氣相層析串連質譜儀（GC-MS）進行香氣成分分析，結果顯示各處理組的主要成分均為檸檬油醇（geranial）及橙花醛（neral），兩者合計約佔89.53-98.48%，其餘主要香氣成分為橙花醇（nerol）、香葉醇（geraniol）、甲酸香葉酯（geranyl formate）、乙酸香葉酯（geranyl acetate）、以及β石竹烯（β-caryophyllene）。 7 levels of nitrogen concentration solution (0 mM, 4 mM, 8 mM, 12 mM, 16 mM, 20 mM, 24 mM) were applied to Melissa officinalis, M. officinalis 'Quedlingburger' and M. officinalis 'Citronella' respectively for 8 weeks, twice a week continuously and each time 300 mL. With the rise of nitrogen concentration, the number of shoot and leaf also increased. M. officinalis treated by 20 mM N had the highest number of shoots and M. officinalis 'Quedlingburger' and M. officinalis 'Citronella'. M. officinalis treated by 16 mM N had the highest number of leaves and M. officinalis 'Quedlingburger' and M. officinalis 'Citronella'. M. officinalis treated by 20 mM N had the highest dry weight of aboveground part, as well as M. officinalis 'Quedlingburger' and M. officinalis 'Citronella' treated by 24 mM treatment. M. officinalis and M. officinalis 'Citronella' treated by 16 mM N had the highest essential oil per unit fresh weight, as well as M. officinalis 'Quedlingburger' with 8 mM treatment. M. officinalis and M. officinalis 'Quedlingburger' treated by 24 mM N had the highest essential oil per unit dry weight, as well as M. officinalis 'Citronella' with 16 mM treatment. The composition of essential oil analysed by SPME and GC-MS showed that the main compounds of M. officinalis, M. officinalis 'Quedlingburger' and M. officinalis 'Citronella' were geranial and neral, approximately composed of 89.53-98.48%. Other main compounds were nerol, geraniol, geranyl formate, geranyl acetate and β-caryophyllene.