バラ花弁の色調発現の研究 (第8報)

Abstract

The transmittance curves were studied on petal extracts from red roses which were prepared using the acids inherent to the petals. Cultivars used were 'Happiness' and ' Bonne Nuit', the representative ones in a whole series of this study. The measurement of component acids in the petals indicated that the total amount of non-volatile acids was about fifty times as much as that of the volatile acids, in which carbon dioxide was a major component. Non-volatile acids in the petals were identified by paperchromatography using the following solvents: butyl formate 10ml, formic acid 4ml, water 1ml; phenol 3ml, water 1ml, 90% formic acid 1%; chloroform 2ml, ethanol 1ml, 90% formic acid 2%. The chromatograms showed that in the petals examined, phosphoric and malic acids predominated, while citric and succinic acids were present at lowest level. Fumaric acid was scarecely detected.On the basis of this fact, petal extracts were prepared using 0.1N solutions of phosphoric, malic, citric and succinic acids, respectively. Similar solutions containing both phosphoric and malic acids in the ratios of (2:1), (1:2) and (1:1) were also applied for extraction.Spectral transmittance was measured on these extracts. No significant difference was observed in the curves obtained here. At a higher concentration of cyanin, the transmittance curves were similar to the reflectance curves of red petals.