THE VERNALIZATION ON MEDICINAL AND OIL PLANTS, II : "YAMAJISO"(MOSLA JAPONICA MAXIMOWICZ) (1) THE INFLUENCE OF VARIOUS TEMPERATURE ON ITS DEVELOPMENT AND ESSENTIAL OIL

Abstract

I. As for a method to analize the vernalization phase of plants, we suggest one consisting of three stages as follows. In the first stage ; a preliminary test is under the conditions of a certain temperature, moisture(moisture content of seeds) and period to discover the proper method of vernalization according to the nature of each kind of plants. In the second stage ; we vernalize at various temperatures, and analize the influence of the temperature on the plants. On this occasion it is better to keep the moisture and period constant, but if it is difficult, one of them is made to change suitably. In the third stage ; we clarify the influence of moisture and period on plants at the most effective temperature. II. On April 12,1956,we sowed three groups of "yamajiao" seeds vernalized at 25℃ for 4 days, at 15℃ for 6 days and at 5℃ for 10 days respectively, together with the unvernalized control. This experiment belongs to the second stage mentioned above. "Yamajiso" contains essential oil(Oleum Moslae)of which the main constituent is thymol. Thymol serves as an insecticide. 1) The 25℃-treated group is the best in promoting the development of plants. The height of plants, the yield of crop and the thymol content of this group are the greatest in those of the three groups and the control. It seems that this group is most advantageous in cultivation. 2) The 15℃-treated group promotes the development next to the 25℃-treated one. The height of plants, the yield of crop and the thymol content of this group are almost equal to those of the control. 3) The 5℃-treated group promotes the development only a little. The height of plants, the yield of crop and the thymol content of this group are lower than those of the control.