Physiological and Ecological Studies on the Secretory Function of Essential Oil in Pelargonium species : IX. The rate of oil distillation of Pelargonium and the composition of its essential oil and their biochemical changes (External conditions)

[摘要] The effect of seasons, time and plant environments on the rate of oil distillation and the fluctuation of the composition of the essential oil were studied and their structures were biochemically examined. 1) Seasonal Effect: (A) The quantities of oil distillation in each period in different seasons were compared and it was found that in the season of high temperatures, when the rate of oil distillation was high, the .quantity in each period of distillation was generally higher due to the increase of the function of oil secletion in such a season, and especially noted that it was pretty high in after-distillations. (Table 1 & 2, Fig. 1). (B) In fractional distillations the fluctuation of the composition of the essential oil was examined and it was found that the total alcohol %, ester % and ketone % were high in initial distillation and low in after-distillations, but so far as acid number was concerned it was low in initial distillation and high in after distillations (Fig, 2). (C) In the examination of seasonal fluctuations of the composition of the essential oil, the fluctuations of the total alcohol %, ester % and format % were almost equal; that was high in May and June and then became low in the period of high temperatures, when the rate of oil distillation was higher, and again got higher in the months of October and November. The cause of these fluctuations was that the quantity of after-distillations increased during the high temperature season. The fluctuations of free alcohol % and ketone % and acid number were similar and showed an opposite tendency in the composition mentioned above. The cause of this phenomenon was assumed to be that free alcohol and acid increased during the high temperature season due to the decomposition of ester (especially formate) and also due to that ketone % increased by the acidification of alcohol (Fig. 3). 2) Daily Fluctuation: (A) By the examination of the daily fluctuations of oil distillation quantity by period it was found that the increase of the rate of oil distillation was due to the increase in after-distillations. (Table 3, Fig. 4). (B) Between the oil remained in the residuum of distillation in each period (by n. Hexane extraction) and the oil distilled by steam distillation there existed an inverse relation quantitatively. (Fig. 5). (C) In the examination of the daily fluctuations in the composition of the essential oil it was found that the atmospheric temperature and the amount of sunshine had a certain influence on the mutual conversion between ester and free alcohol (Fig. 6). 3) Plant Environments: No significant difference was found in the composition of the essential oil due to the elements and quantity of fertilizers used and the percentage of moisture in the soil. 4) Terpene and Terpene Glucoside: After the hydrolysis by means of NaOH the fractions from steam distillation increased. By this the existence of terpene glucoside could be assumed. By the examination of the seasonal fluctuation of the glucoside it was found that it existed in a high quantity during the period of the high rate of plant growth and low during the period of the low rate of growth (Table 4). From the foregoing statement, as the fluctuating structure in oil distillation, the possibility of the mutual conversion between volatile oil and oil not easily distillable by steam distillation and also that of the mutual conversion between free alcohol and terpene glucoside were conceivable, and the atmospheric temperature and the amount of sunshine were assumed as the possible chief elements influencing such conversions.

[学科分类] 农业科学（综合）