Synthesizing site and storing position of essential oil in Pogostemon cablin / 中草药

ABSTRACT

Objective To study the synthesizing site,transporting mode,and storing position of essential oil in Pogostemon cablin stems and leaves.Methods Ultrathin slicing and histochemical methods were used.Results In parenchyma cells in the stem of P.cablin,dark osmiophilic material was observed in plastids and mitochondria,otherwise,some small gray vesicles were also found in cytoplasm.Some dark osmiophilic droplets were found to adhere to outer membrane of small gray vesicles,and many small gray vesicles with osmiophilic droplets gathered in outer membrane of large vacuole.In leaves,it was different case.Because palisade tissue cells were arranged closely,which had smaller volume and rich chloroplasts,so there was not large vacuole in palisade tissue cells.Plastids,mitochondria,and small vacuole were distributed in high density,but the first two organelles contained more dark osmilphilic substance than latter.Conclusion The plastid is the main synthesis site of essential oil,and the essential oil was mainly transferred by small gray vesicles into large vacuole to store in the stem.In leaves,chloroplast not only has photosynthesis,but also is the main synthesis site of essential oil,and essential oil is permeated into small vacuole to store.