Mobilization of Starch and Essential Oil Biogenesis during Leaf Ontogeny of Lemongrass (Cymbopogon flexuosus Stapf.)

スポンサーリンク

概要

• 論文の詳細を見る

• The levels of starch, soluble sugars, starch mobilizing enzymes (amylases and phosphorylase) and sodium [2-^<14>C]acetate incorporation into essential oil have been examined during leaf ontogeny of lemongrass (Cymbopogon flexuosus Stapf., cv. OD-19). The degradation of starch was predominantly amylolytic and β-amylase was the major enzyme involved. Its activity was quite high during the period of active leaf growth accompanying active accumulation of essential oil. The activities of α-amylase and phosphorylase were relatively lower. The change in starch to soluble sugars ratio was inversely related to β-amylase activity. The time-course (12 h light followed by 12 h dark) monitoring of the [^<14>C]-radioactivity in starch and essential oil, after exposure of the immature (15 days after emergence) leaf to ^<14>CO_2, revealed a progressive loss of label from starch and a parallel increase in radioactivity in essential oil. The results have been discussed in relation to degradation of transitory starch serving as the source of carbon precursor for essential oil (monoterpene) biogenesis in the tissue. The amount of exogenously supplied acetate incorporated into essential oil increased tremendously with 5-10 fold decrease in specific activity of the labelled acetate (2,110 GBq mole^<-1>). The effect was largely manifested in 'citral', the chief (ca. 80%) constituent of lemongrass essential oil. Ontogenetically, the amount of essential oil synthesized from the exogenously supplied precursor (acetate) was much higher in young (10 days after emergence) than in mature (30 days after emergence) leaf. Thus, the leaf develop-mental phase influences the expression of essential oil metabolism and actual synthesis. Only young lemongrass leaves are substantially active to synthesize essential oil. The oil biosynthetic phase appears to be coordinated/integrated with the development of elevated levels of certain primary metabolic activities like starch mobilization.

• 日本植物生理学会の論文

著者

• Sangwan Rajender

  Plant Biochemistry Laboratory Central Institute Of Medicinal And Aromatic Plants (csir):(present)dep

• Singh Neelam

  Plant Biochemistry Laboratory, Central Institute of Medicinal and Aromatic Plants (CSIR)

• Luthra Rajesh

  Plant Biochemistry Laboratory, Central Institute of Medicinal and Aromatic Plants (CSIR)

• Singh Neelam

  Plant Biochemistry Laboratory Central Institute Of Medicinal And Aromatic Plants (csir):(present)csi

• Luthra Rajesh

  Plant Biochemistry Laboratory Central Institute Of Medicinal And Aromatic Plants (csir)

関連論文

• Mobilization of Starch and Essential Oil Biogenesis during Leaf Ontogeny of Lemongrass (Cymbopogon flexuosus Stapf.)

スポンサーリンク