Mitsuru Hotta

Mineral composition of leaves and bark in aluminum accumulators in a tropical rain forest in Indonesia

Abstract Mineral composition including AI, Ca, Mg, P, S, and Si and relationships between Al and other elements such as Ca, Mg, P, S, and Si in leaves and bark of trees in a tropical rain forest in West Sumatra were studied. Sixty five tree species and 12 unidentified trees were referred to as AI accumulators based on Chenery\ss definition (more than 1 g kg-1 Al in leaves). For most of the Al accumulators, Al concentration in leaves was higher than in bark. However, some members of Euphorbiaceae, Melastomataceae, and Ulmaceae families showed a reverse trend. Most of the non-accumulators also showed a higher Al concentration in bark than in leaves. These results indicated that there was a difference in the mechanism of Al accumulation in tree bodies. Some of the Al accumulators showed an extremely high Al concentration (more than 10 g kg-1) not only in the mature leaves, but also in the new leaves. Analysis of the relationships between the concentration of Al and the other 5 elements in leaves, revealed t...

Inter- and intra-specific variation in prey assemblages and inhabitant communities in Nepenthes pitchers in Sumatra

Prey assemblages and inhabitant communities in pitchers were compared among 10 Nepenthes Linnaeus 1753 species with various pitcher morphologies in West Sumatra, Indonesia. There were significant differences in the number of prey organisms trapped per pitcher among Nepenthes species and among pitcher ages but no significant differences among localities nor between the vertical positions of pitchers. Prey assemblages of eight Nepenthes species were predominated by ants. Nepenthes bongso Korthals 1839 and N. albomarginata Lobb 1849 had prey assemblages characterized by high frequencies of midges and termites, respectively. Pitchers captured prey organisms not by random trapping but by attracting specific groups of organisms. Inhabitant fauna was largely similar among Nepenthes species except for N. bongso which fostered no inhabitants. The typical inhabitant community was composed of Toxorhynchites Theobald 1901 larvae as aquatic predators, culicid larvae as filter feeders and ceratopogonid larvae as detrit...

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 cha...

Pollination Ecology of the Two Wild Bananas, Musa acuminata subsp. halabanensis and M. salaccensis: Chiropterophily and Ornithophily

The two Sumatran wild bananas, Musa acuminata subsp. halabanensis and M. salaccensis, belonging to the different sections Musa and Callimusa respectively, have contrasting flowering traits corresponding to their different pollination syndromes: i.e., chiropterophily and ornithophily, respectively. The M. a. halabanensis flowers, on pendent inflorescences with dark purple bracts, produced jelly-like nectar of 22-25 percent sugar concentration primarily at night, and were pollinated by the nectarivorous pteropodid bats, Macroglossus sobrinus. In contrast, the M. salaccensis flowers, on erect inflorescences with purplish pink bracts, produced dilute nectar of 18-21 percent sugar concentration primarily in the daytime, and were pollinated by the nectarivorous nectariniid birds, Arachnothera longirostris and Aethopyga siparaja. The flowering span of each female flower was 24-40 hr, while that of the male flowers was < 12 hr. Open flowers of both species contained significantly less outcrop of nectar than bagged flowers. Fruit weight and seedset of open M. salaccensis flowers were significantly more than those of bagged flowers and were significantly less than those of hand-pollinated flowers.

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

Abstract The nutritional characteristics of mineral elements in tree species were studied in a 1 ha permanent observation plot at Mt. Gadut area near Padang, West Sumatra, Indonesia. The elemental composition of the 42 leaf and the 457 bark samples from the 1 ha plot was analyzed. Most of the elements, such as S, K, AI, CI, Si, B, and Sr, showed a significant correlation between leaf and bark, suggesting that bark can also be used to study the nutritional characteristics of trees instead of leaves as the first approximation. The concentrations of elements in 457 bark samples showed a wide range, indicating the considerable diversity of nutritional characteristics of mineral elements among these tree species. The concentration ranges expressed in mg kg-1 were Mn (0.1–3,800), Sr (0.1–1,070), Si (2–1,700), Fe (0.6–4,100), Al (10–46,000), Mg (10–7,200), Zn (0.4–290), K (60–22,000), Cu (0.8–150), P (19–2,540), CI (110–9,200), S (170–13,600), Ca (2,300–100,000), B (4–70), and N a (130–700). Accumulator species ...

Molecular phylogenetic position of podostemaceae, a marvelous aquatic flowering plant family

Podostemaceae are aquatic herbs and are famous for their anomalous vegetative morphology, occurring only in rapids. Because of its peculiar morphology, there were no established theory nor accepted opinion on the phylogenetic position. Especially, Cusset and Cusset (1988) proposed the new class, Podostemopsida beside the Magnollopsida and Liliopsida. We, therefore, consequences extensive and detailled analyses using nucleotide sequences ofrbcL genes for two genera and three species of the family together with many representatives of the families of flowering plants to determine the closest ally. The conclusion was that the Crassulaceae is a sister group to the Podostemaceae.

Foliage-canopy structure and height distribution of woody species in climax forests

The correlation between foliage-canopy structure and vertical woody species distribution was examined in seven climax forests ranging from alpine tree limit to tropical rain forest. Foliage density was measured by two-dimensional canopy tomography using photographs.Both foliage density and the vertical species density (the number of woody species having a maximum height within a vertical 1 m) were high in the upper canopy of warm-temperate and subtropical forests, but they were high at lower stratums in the tropical rain forest. Two variables correlated significantly despite the differences in foliage-canopy structures. In contrast to evergreen broad-leaved forests, a clear correlation could not be detected in northern cool-temperate and sub-alpine forests.A possible reason for species convergence in the foliage dense stratum is that species with maximum height in that stratum may be able to survive in the stratum due to symmetrical crown-to-crown interaction. If the maximum height of dwarf species is less than the foliage dense stratum, it may be difficult to survive in the community. The lack of correlation in northern forests may be due to poor canopy tree flora and a mixture of different life forms (non-sprouting trees and sprouting shrubs).

Soil environment and tree species diversity in tropical rain forest, West Sumatra, Indonesia

Soil characteristics were examined in relation to tree species diversity of a tropical rain forest on a 100 m transect plot covering from ridge to valley with 0.10 ha and a long-term observation plot, 1.0 ha, in Mt. Gadut area near Padang, West Sumatra, Indonesia. The area experienced an annual rainfall of more than 6000 mm with no real dry season. In the 0.10 ha transect plot, detailed soil characterization was performed. From each sub-plot having the measurements of 5 × 5 m, 5 samples were taken from each 0–5 and 5–15 cm depth. In this transect plot, the subplots positioned on the ridge showed a greater diversity of tree species and higher biomas than those positioned in the valley. Soils found on the ridge showed less fertility and greater variation of fertility characteristics than those found in the valley. The examination of vertical soil profile distribution of ridge, middle and valley positions in this transect also revealed that exchangeable Calcium, total carbon and total nitrogen of ridge soil tended to accumulate of these nutrients at the upper horizons and of dissipation at lower horizons more than those of valley soil profile. Detailed characterization of 115 subplots of 1.0 ha permanent plot showed that horizontal variations of soil fertility characteristics were also important in relating the tree species diversity of tropical rain forest. These results suggest that both vertical and horizontal variations of soil characteristics are imperative in supporting the tree species diversity.

Distribution characteristics of mineral elements in trees of tropical rain forest, West Sumatra, Indonesia

The distribution of mineral elements in trees and soils in a 1 ha permanent observation plot on mixed dipterocarp forest in West Sumatra, Indonesia was studied. Seven elements, including S, K, AI, CI, Si, G and Sr, revealed significant correlation between leaves and barks, suggesting that barks can also be used to study the nutritional characteristics of trees instead of leaves as the first approximation. The concentrations of elements in 457 different samples of bark showed quite a wide range, indicating the enormous diversity of nutritional characteristics of mineral elements among these tree species. The concentration ranges in mg kg−1 were Mn (0.1–3800), Sr (0.1–1070), Si (2–1700), Fe (0.6–4100), Al (10–46000), Mg (10–7200), Zn (0.4–290), K (60–22000), Cu (0.8–150), P (19–2540), CI (110–9200), S (170–13600), Ca (2300–100000), B (4–70) and Na (130–700).