Nutritional characteristics of mineral elements in leaves of tree species in tropical rain forest, west Sumatra, Indonesia

Abstract

The nutritional characteristics of mineral elements in tree species were studied in a 1 ha ecological observation plot at Mt. Gadut area near Padang, West Sumatra, Indonesia. The elemental composition of the 608 leaf samples from the plot was analyzed and was compared with the results of bark analyses (Masunaga et al. 1997: Soil Sci. Plant Nutr., 43, 405–418). The concentration ranges of various elements in leaves (in mg kg-1) were S (470–17,000), K (1,040– 34,430), Al (6–36,920), Ca (500-81,700), Mg (170-10,530), Si (250-89,980), N a (131– 861), Cu (0.8-63.7), Fe (38-851), Mn (4.8-3,574), P (357-4,350), Sr (0.1-690), and Zn (0.4-309), respectively. The concentration of the most of the elements such as S, K, AI, Mg, Si, Cu, Fe, Mn, P, and Zn was higher in leaves than in bark, especially Si and P, being more than seven times higher in leaves. However, the coefficient of variation was conversely higher in bark for most of the elements, suggesting that there are larger differences in nutritional characteristics in bark than in leaves. Accumulator species were defined as trees with concentrations higher than logarithmic mean + 2S.D., whereas excluder species were defined as trees with concentrations lower than logarithmic mean — 2S.D., among 137 identified species and other unidentified trees. Aluminium accumulators accounted for the largest number of species, 14 species and 4 unidentified trees. Some genetic commonality was recognized in the Aporusa genus in the Euphorbiaceae family, Melastomataceae, Rubiaceae, and Theaceae for Al accumulators. The results for accumulator and excluder species which corresponded to the results of analyses from bark were A. maingayi, M. laurinum, and S. javensis for S accumulators, A. frutescens, A. maingayi, M. laurinum, M. corymbosus, and E. acuminata for Al accumulators, G. macrophylium for Na and P accumulators, A. malaccensis for Zn accumulator, and P. grandis for Mg excluder. The species of S or Al accumulators showed a relatively high correlation between the results from leaves and bark. However, most of the accumulator and excluder species were different from those defined from bark, indicating that there were several types of accumulators and excluders in terms of elemental distribution in leaves and bark. These wide variation in nutritional characteristics in terms of elemental concentration and distribution in leaves and bark reflect the diversity of species in this plot. © 1998, Taylor & Francis Group, LLC.