Biodegradation of organic components of Japanese cedar [Cryptomeria japonica] leaf litter, 2: On the components of 2nd and 3rd year's rotten litter
1990
Kawakami, H. (Nagoya Univ. (Japan). Faculty of Agriculture) | Banno, H. | Kutuna, S.
In the preceding paper, we reported the biodegradation of organic components of Japanese cedar leaf litter on the forest floor for up to 14 months. This time also keep to investigating the biodegradation of organic components of the leaf litter for 18 to 38 months, the final period of biodegradation (A series). Alternative leaf samples in litter bag put on the forest floor after 1 year were also analyzed (B series). The extractives and carbohydrates of the leaf litters changed largely in early time of biodegradation and little changes were found in final period. On the other hand, cutin was relatively easily degraded and completely decomposed in 20 to 30 months. Klason lignin contents of the leaf litters changed largely in the first period of biodegradation and contents was reached about 60% in the final period of biodegradation. The Klason lignin contained 1% or more nitrogen. The lignin contents of the leaf litter on the thioglycolic acid method showed one half of the Klason lignin content. The thioglycolic lignin, however, contained 0.8% of nitrogen. The excess values of the Klason lignin from neadle leaves and leaf litters might be attributed to the influences of cc-existent nitrogen containing compounds. To make sure this assumption, protein, amino acids, and purine bases were treated with sulfuric acid (Klason method), respectively, and no precipitation was founded. It was clarified that when the proteins co-existed with milled wood lignin, the excess values of Klason lignin contents occurred. It is assumed that humic substances which contained nitrogen to a generally lesser extent than proteins, behaves like protein and co-precipitation occurs with milled wood lignin or precipitation itself on Klason treatment
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