Abstract
Changes in oil and chemical components of leaf associated with its growth were studied to obtain the information about the oil accumulation process of mint plant with the following results. 1. Free menthol content increased with leaf growth, but menthone content decreased conversely. Amount of menthone increased with growth in early growing stage, attained to maximum before leaf complete formation, then decreased while the amount of free menthol still increasing. That is, the same general results were secured with the former report which dealed with entire plant in its successive growth. 2. Evidence to support FUKUSHIMA'S hypothesis that oil ameunt might be decreased by volatilization in lower leaves was not afforded. Decrease of oil in lower leaves was not recognized always. It might be caused by the difference of internal or enviromental conditions during the leaf growth. 3. From the results obtained it was suggested that nitrogen, especially α-amino acid and phosphorus play an important role in the oil accumulation process. 4. It seemed that nitrogenous assimilation was more essential in the biogenetic mechanisms of oil formation than photosynthetic reaction.
