NUTRITIONAL CHARACTERISTICS OF MINERAL ELEMENTS IN LEAVES OF TREE SPECIES IN TROPICAL RAIN-FOREST, WEST SUMATRA, INDONESIA

The nutritional characteristics of mineral elements in tree species we re studied in a 1 ha ecological observation plot at Mt. Gadut area nea r Padang, West Sumatra, Indonesia. The elemental composition of the 60 8 leaf samples from the plot was analyzed and was compared with the re sults of bark analyses (Masunaga et al. 1997: Soil Sci. Plant Nutr., 4 3, 405-418). The concentration ranges of various elements in leaves (i n 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); Na (131-861), Cu (0.8- 63.7), Fe (38-851), Mn (4.8-3,574), P (357-4,350), Sr (0.1-690), and Z n (0.4-309), respectively. The concentration of the most of the elemen ts such as S, IC, Al, Mg, Si, Cu, Fe, Mn, P, and Zn was higher in leav es than in bark, especially Si and P, being more than seven times high er in leaves. However, the coefficient of variation was conversely hig her in bark for most of the elements, suggesting that there are larger differences in nutritional characteristics in bark than in leaves. Ac cumulator species were defined as trees with concentrations higher tha n logarithmic mean+2S.D., whereas excluder species were defined as tre es with concentrations lower than logarithmic mean-2S.D., among 137 id entified species and other unidentified trees. Aluminium accumulators accounted for the largest number of species, 14 species and 4 unidenti fied trees. Some genetic commonality was recognized in the Aporusa gen us in the Euphorbiaceae family, Melastomataceae, Rubiaceae, and Theace ae for Al accumulators. The results for accumulator and excluder speci es which corresponded to the results of analyses from bark were A. mai ngayi, M. laurinum, and S. javensis for S accumulators, A. frutescens, A. maingayi, M. laurinum, M. corymbosus, and E. acuminata for Al accu mulators, G. macrophyllum for Na and P accumulators, A. malaccensis fo r Zn accumulator, and P. grandis for Rig excluder. The species of S or Al accumulators showed a relatively high correlation between the resu lts from leaves and bark. However, most of the accumulator and exclude r species were different from those defined from bark, indicating that there were several types of accumulators and excluders in terms of el emental distribution in leaves and bark. These wide variation in nutri tional characteristics in terms of elemental concentration and distrib ution in leaves and bark reflect the diversity of species in this plot .