Studies on the Development, the Essential Oil Content and the Environmental Conditions in Pelargonium Species

Abstract

I . The Process of Development and the Vicissitude of the Ingredients in Pelargonium Plant As the result of the trial examinations on the process of the development and vicissitude of thet ingredients of P. denticulatum and Bourbon species in Seto Naikai (the Inland Sea) zone, the process of development is divided into four stages, the first growing period, the standstill period, the second growing period and the third growing period. The first growing period shows extensible increase, namely, increase in the number of the first offshoots, the stalk length, the leaf weight and the essential oil content. The second growing period shows luxuliant development to increase the number of the second offshoots. The cause of the standstill, period between the first and the second growing period, depends upon the want of soil moisture due to the drought in summertime, and both in the top and underground parts of herb the physiological changes are observed. (Fig. 1) On the vicissitude of the ingredients Content in the top: (1) Nitrogen content is maximum at the begining of July when the oil content is great, low in the standstill period, and increases again in the second growing period. (2) P2O5 increases till the middle of August, decreses in the standstill period and increases again thereafter. (3) K2O increases till dry season, and then decreases gradually until the third growing period, when slight increase is observed. (4) CaO shows the greatest change of all the ingredients, It decreases in dry season but increases again early in September. Concerning the change of oil content, the characteristics appeared in the vicissitude of the ingredients content of the herb is as follows: Both in the development and in the ingredients Content of geranium in Seto-Naikai zone there are two extremes: high and low, Which appeared directly in the vicissitude of CaO. This fact is considered to be very important problem for the cultural management to increase the essential oil yield. It will be necessary to examine the better growing method to prevent the defoliation and the excessive debility by reaping the herb by early or middle July when the weight of the herb shows the maximum, and to shorten the standstill period, and to lengthen the second growing period. (Fig. 2) II. On the Environmental factors and the Mechanism deciding the Development and the Percentage of Oil Yield As the result of observing the raw material composition classified by the leaf position, and the oil yield V. the percentage of oil yield in the green herb, under the different reaping time, of the raw herb, the percentage of oil yield is first decided by the raw herb composition and by the degree of drying after reaping. (Fig. 1) Moreover, as the percentage of oil yield from the prescribed materials shows a remarkable change in accordance with the reaping time in season and in day, the influence of the enviromental conditions are examined by dividing into the climatic conditions and the cultural conditions (elements of fertilizer, kinds of soil, quantity of sprinkling and the density of planting). The results are as follows: (1) Loam or Sandy loam is mosft suitable and Sand is also suitable for the cultivation of geranium, while Clayey soil of ill-drain bring poor development and low yield of oil. (2) The effect of sprinkling water in dry season is so conspicuous that the yield of oil from green herb increase despite of slightly low percentage of oil yield. (3) Close spacing bring the increase of quantity of green herb, and lower the percentage of oil yield. As compared with the described section, close spacing has lewered the first year plants by 9% in number, and the second year plants by 10%, and extreme close spacing lower the first year plants by 17%, and the second year plant by 19% (Fig. [the rest omitted]