Satomi Watanabe

Changes in lignin content of leaf litters during mulching

Alkaline nitrobenzene oxidation, ozonation and methoxyl content determinations were applied to decomposing leaf litter of Ginkgo biloba L., Cinnamomum camphora sieb., Zelkova serrata Makino and Firmiana simplex W. F. Wight, respectively, during mulching to investigate the properties and estimate changes in lignin composition and content. Since the Klason lignin residue originated from components highly resistant to degradation by acid, the methoxyl content of Klason residue was used to estimate the lignin content of leaf litter. Quantitative analysis of presumed lignin-derived fragments, by use of alkaline nitrobenzene oxidation and ozonation methods, suggested that the estimated lignin content approximates that of the real lignin content of leaves, which is greatly overestimated by the Klason procedure. The estimated lignin contents ranged from 3.9 to 10.0% while the Klason lignan residue varied from 37.1 to 46.7% in un-mulched leaf litter. The absolute amounts of the measured lignin somewhat decreased during mulching, while the structure of lignin remaining in leaf litters after mulching was considered not to be very different from its original structure.

The Scent of Lotus Flowers

ABSTRACT A solvent extract of Nelumbo nucifera ‘Shinnyoren’ flowers was investigated by GC and GC/MS. Seventy compounds were identified with the major constituents being hydrocarbons representing more than 75% of the extract. 1,4-Dimethoxybenzene, 1,8-cineole, terpinen-4-ol and linalool were found to be indispensible in characterizing the scent of lotus flower. Using headspace analysis, the volatiles of 44 cultivars of N. nucifera, one cultivar of N. Pentapetala and four hybrids were compared chromatographically. Although 1,4-dimethoxybenzene was found to increase daily during anthesis, it was found to be at a higher concentration in N. pentapetala of American origin than in N. nucifera of Oriental origin.