title: On the relationships between leaf-litter lignin and net primary productivity in tropical rain forests.
abstract: We investigated if tropical rainforest trees produced more-lignified leaves in less productive environments using forests on Mount Kinabalu, Borneo. Our investigation was based on two earlier suggestions that slower litter decomposition occurs under less productive forests and that trees under resource limitation invest a large amount of carbon as lignin as a defense substance to minimize the loss from herbivores. When nine forests at different altitudes (700-3100 m) and soil conditions (derived from sedimentary or ultrabasic rocks) but with the same gentle relief position were compared, the concentrations of leaf-litter lignin were positively correlated with litterfall rates and leaf-litter nitrogen concentrations. These patterns would be reinforced in intact leaves if the effects of resorption at the time of leaf shedding were taken into account, because greater magnitude of resorption of mobile elements but not of lignin would occur in less productive environments (i.e. dilution of lignin in intact leaves). These results did not support earlier suggestions to explain the variation of leaf-litter lignin. Instead, we suggest that lower lignin contents are adaptive to recycle minerals without retarding decomposition in less productive environments.
authors.affiliation: Center for Ecological Research, Kyoto University, Kamitanakami Hirano-cho, Ohtsu, Shiga 520-2113, Japan. kitayama@ecology.kyoto-u.ac.jp
authors.forename: Kanehiro
authors.initials: K
authors.lastname: Kitayama
authors.forename: Shizuo
authors.initials: S
authors.lastname: Suzuki
authors.forename: Masato
authors.initials: M
authors.lastname: Hori
authors.forename: Masaaki
authors.initials: M
authors.lastname: Takyu
authors.forename: Shin-Ichiro
authors.initials: S
authors.lastname: Aiba
authors.forename: Noreen
authors.initials: N
authors.lastname: Majalap-Lee
authors.forename: Kihachiro
authors.initials: K
authors.lastname: Kikuzawa
mesh_terms: D000531:Altitude; D018533:Biomass; D001893:Borneo; D008031:Lignin / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis; D018515:Plant Leaves / Q000737:chemistry*; D014197:Trees; D014329:Tropical Climate
chemical_list: D008031:Lignin; D009584:Nitrogen