[Research on effects of chemotype and components of Perilla frutescens leaf volatile oil I: different phenological periods]

This experiment researched on three kinds of Perilla frutescens including the widespread PK, PA and rare PL chemotype. The Perilla samples were the mature leaves collected in nutrition, flowering and frutescence three different phenological periods, and at 7 am, 12 pm and 6 pm three day time. The volatile oil was extracted by steam distillationand analyzed by GC-MS, as a result, the three chemotype samples'volatile oil yield was between 0.08% and 0.96%; volatile oil yield of different growth period was as follow: nutrition>flowering>fructescence, and the volatile oil yield of nutrition period: PA type>PK type>PL type. Each chemotype was not affected by the growth and development, indicating that the chemotype is determined by genetic factors. Characteristic and main components of PA and PK type are relatively stable, and the characteristic components of PL type are significantly decreased with the growth. There are still a large number of upstream metabolism components, and the chemical type may have their primitiveness and changeability. The relative content of perillaldehyde, characteristic components of PA type, is basically decreased from morning to night, in all the period. The relative content of perillaketone, characteristic components of PK type, in nutrition and flowering period, when samples were collected at 12 noon is relatively higher than that at 7 am and 6 pm, and contrary to samples collected in frutescence period. The relative content of perillene, characteristic components of PL type, in nutrition and frutescence period are highest at 12 noon, while in flowering period is highest at 6 pm. According to the volatile oil yield and relative content of maincomponents, the best harvest time of PA type is in the morning of the nutrition period; the best harvest time of PK type is in the morning of all the period; and the best harvest time of PL type is at dusk of the nutrition period.