bluuebunny/crossref_metadata_2025 huggingface dataset:
In Situ Raman Study on Single‐ and Double‐Walled Carbon Nanotubes as a Function of Lithium Insertion
Authors: Kim Yoong Ahm , Kojima Masahito , Muramatsu Hiroyuki , Umemoto Souichiro , Watanabe Takaaki , Yoshida Kazuto , Sato Keigo , Ikeda Takuya , Hayashi Takuya , Endo Morinobu , Terrones Mauricio , Dresselhaus Mildred S.
Published: March 2006

We investigated the electrochemical lithium ion (Li+) insertion/desertion behavior on highly pure and bundled single‐ and double‐walled carbon nanotubes (SWNTs and DWNTs) using an in situ Raman technique. In general, two storage sites could host Li+ in SWNT and DWNT bundles when varying an external potential: a) the outer surface sites, and b) the interstitial spaces within the bundles. The most sensitive changes in the tangential mode (TM) of the Raman spectra upon doping with Li+ can be divided into two regions. The first region was found from 2.8 to 1.0 V (the coverage of Li+ on the outer surface of a bundled nanotube) and was characterized by the loss of resonant conditions via partial charge transfer, where the G+ line of the SWNT and the TM of the outer tube of DWNTs experienced a highly depressed intensity, but remained almost constant in frequency. The appearance of a Breit–Wigner–Fano (BWF) profile provided strong evidence of metallic inner tubes within DWNTs. The second region was observed when the applied potentials ranged from 0.9 to 0 V and was characterized by Li+ diffusion into the interstitial sites of the bundled nanotube material. This phenomenon invoked a large downshift of the G− band in SWNTs, and a small downshift of the TM of the inner tube of DWNTs caused by expansion of the CC bonds due to the charge transferred to the nanotubes, and the disappearance of the BWF profile through the screening effect of the interstitial Li+ layers.
Green's function for radially symmetric waves in inhomogeneous anisotropic solids
Authors: Watanabe K. , Payton R.G.
Published: March 2006

An exact Green's function is presented for radially symmetric waves in cylindrically inhomogeneous anisotropic solids. It is found that the wave which passed through the center (coordinate origin) looses the logarithmic singularity at its front, when a material parameter is a half of odd integer. Further, the time‐harmonic Green's function is derived. It is also found that the wave nature of the Green's function vanishes when the wave velocity is a linear function of the radial distance.
Superconvergence on a hybrid mesh for singularly perturbed problems with exponential layers
Authors: Roos H.‐G.
Published: March 2006

We consider singularly‐perturbed model problems with exponential boundary layers and its discretization using finite elements on a layer adapted meshes using rectangles in the layer region and triangles outside. We study superconvergence properties of the method.
Death at the zoo: the media, science, and reality
Authors: Hutchins Michael
Published: March 2006

Media characterizations of zoo and aquarium animal deaths were randomly monitored on the internet for a 20‐month period (September 2003–May 2005). Based on 148 samples collected, it was possible to classify articles into one of four categories, which were operationally defined: 1) dispassionate observers; 2) accusers; 3) sympathizers; and 4) balancers. In addition, with the notable exception of seven cases, all of the articles examined focused on large, charismatic mammals, such as gorillas, dolphins, lions, and elephants. Although a majority of the articles examined (70.4%) were either dispassionate and objective or sympathetic, nearly a third (29.6%) were either accusatory or attempted to balance the accusatory statements of animal rights activists with sympathetic statements from zoo professionals. Recommendations are offered for how zoos should deal with the increasing media and public interest in zoo animal deaths, including: 1) a greater commitment to studying the reasons for mortality in a wide variety of species; and 2) an increased investment in record keeping and analysis, which should allow zoos to calculate average life spans in animal populations and to monitor and assess the risk of certain lethal diseases on a real‐time basis. Comparisons are drawn between zoo veterinary practices and human medicine, which are both inexact sciences. Suggestions are made for how the public and key decision‐makers can distinguish between media reports on zoo animal deaths that are legitimate cause for concern vs. those that are sensationalist and meant to generate controversy and sell papers. A greater focus on the science of zoo animal death is necessary for accredited zoos to maintain the public's confidence in their animal care practices. Zoo Biol 0:1–15, 2006. © 2006 Wiley‐Liss, Inc.
Histidinaemia. Part I: Reconciling retrospective and prospective findings
Authors: Scriver C. R. , Levy H. L.
Published: March 2006

We reach the conclusion that histidinaemia in the typical form (autosomal recessive impairment of L‐histidine ammonia lyase activity (EC 4.3.1.3)) is not a ‘disease’ in man. Retrospective and prospective studies (Rosenmannet al., 1983; Coulombeet al., 1983) together indicate that the prevalence of disadaptive phenotypes (e.g. impaired intellectual or speech development, seizures, behavioural or learning disorder) in the histidinaemia population, is not higher than the frequency of these functional disorders in the non‐histidinaemia population. However, one cannot exclude the possibility that histidinaemia is a risk factor for development of an unfavourable CNS phenotype, in particular individuals under specific circumstances (e.g. abnormal perinatal events). From this viewpoint, we propose that newborn screening for early diagnosis and treatment of histidinaemia does not meet the criteria for a public health service. Screening for continuing research on histidinaemia remains justifiable, for example, to discern whether there are atypical forms of the biochemical and enzymatic phenotypes.
Normal glycine transport in cultured diploid fibroblasts from hyperglycinaemic subjects
Authors: Kølvraa S. , Rosleff F. , Brandt N. J.
Published: March 2006

The glycine uptake in cultured fibroblasts was studied in three children with non‐ketotic hyperglycinaemia, one child withd‐glyceric acidaemia and hyperglycinaemia and in six normal children, using an improved assay system giving individual protein correction.

It was shown that all hyperglycinaemic children had normal uptake rates and kinetic characteristics similar to the controls.
Entomological and ecological surveys on Mt. Usu in 1984 VI: Faunal make‐up and ecological distribution of springtails (Collembola) on Volcano Usu
Authors: Sugawara Hiromi , Higashi Seigo , Fukuda Hiromi
Published: March 2006

A survey of springtails was conducted in 1984 on Volcano Usu which suffered damage to it's ecosystem from eruptions in 1977 and 1978. The summit area, almost completely deforested by the eruptions, was still inhabited by many forest species such as Desoria notabilis, Willowsia sp. 2, Pseudachorutes sp. 2, Isotoma sp. 4, Tullbergia yosii, Onychiurus sp. 1, Entomobrya sp. 2, Isotomiella minor, Proisotoma sp. 2, Xenylla sp., Neanura frigida, etc. These species preferred standing or fallen dead trees, mosses, bark chips, former topsoils and soil around the root of plants. The fauna in the summit area was most similar to that of coniferous or broad‐leaved forests surveyed on the foot of the mountain. This suggests that the 1977–78 eruptions did not exterminate these springtail species which probably survived on the standing trees or in the former topsoil.
The ecology of a beech forest on Mt. Sanpoiwadake, Hakusan National Park, Japan I. Braun‐Blanquet, TWINSPAN and DCA analysis
Authors: Hukusima Tukasa , Kershaw Kennth Andrew
Published: March 2006

The Lindero membranaceae‐Fagetum crenatae association on Mt. Sanpoiwadake, Hakusan National Park, Japan, has been classified using traditional Braun‐Blanquet methods. The association was floristically sub‐divided into six communities, all of which had been included as four subassociations by Hukusima (1982). The resulting table was compared with an analogous community table derived using computer‐based TWINSPAN analysis. This dual approach was shown to provide a fully objective classification by method, the subjective element in the Braun‐Blanquet method thus being substantiated TWINSPAN. Subsequent ordination of the data using DCA then provided a further degree of objective evaluation allowing any misclassified stand or species to be re‐examined, and at the same time displaying the detailed inter‐relationships between all species or stands.
Pollination systems in the cool temperate mixed coniferous and broad‐leaved forest zone of Yakushima Island
Authors: Yumoto Takakazu
Published: March 2006

Animal pollination was observed in a cool temperate mixed coniferous and broadleaved forest, and in shrubby vegetation on a mountain summit, on Yakushima Island (30.2°N, 130.3°E), to the south of Kyushu, Japan. In the mixed forest, two groups of plants were recognized: exclusively canopy‐flowering species, and understory‐flowering species. All of the canopy‐flowering species had dish‐shaped flowers or flowers without petals, were visited by opportunist insects, and most of them showed a mass‐flowering pattern. Each segregated its flowering time from those of the others. On the other hand, most of the understory‐flowering species had bell‐or funnel‐shaped flowers which were pollinated by birds or bumble bees, and showed an extended flowering pattern. Their phenological flowering series (except Camellia japonica that was pollinated by birds), without a break, coincided very well with the active period of a bumble bee species, Bombus ardens. In the shrubby vegetation on the mountain summit, two types of species were recognized: one type also grew in the forest, whereas the other type only grew in the shrubby vegetation. The former type of species in this vegetation was visited by a more diverse range of insects than that in the forest. In particular, species visited mainly by bumble bees in the forest attracted many opportunist insects. All but one of the species that only grew in the shrubby vegetation were visited only by opportunist insects and never by bumble bees.
The growth analysis of water hyacinth, Eichhornia crasipes solms, in different water temperature conditions
Authors: Sato Haruo
Published: March 2006

A 40‐day culture experiment of water hyacinth was made in 4 different water temperatures, 15, 20, 25 and 30°C, which were combined with 4 levels of concentration of culture solution, 1/3, 1, 3 and 9‐fold of the standard solution containing 28 ppm of total N and 7.7 ppm of total P. The optimum condition for obtaining the maximum plant growth shifted from 30°C: 3‐fold condition in the early stage to 20–25°C: 3‐fold condition in the later stages of the experiment. The relation between the fresh weight biomass per 100‐l tank, w, and the concentration of culture solution, f, was expressed successfully by a reciprocal equation, 1/w=A F/f+A F′f/(1‐f/C F)+B F, in which Af, Af′, and Bf are time dependent coefficients and Cf is the upper limit of the concentration to permit plant growth which can change with time. The relation between w and water temperature, T, was expressed by another reciprocal equation, 1/w=A T/eaT+A T′ebT+B T, in which a and b are constants and AtAt′ and Bt are time dependent coefficients. The latter formulation shows that the temperature can be breated as an exponential factor, and it suggests the possibility of the growth coefficient of the logistic growth equation, ψ, being affected by temperature.
Aboveground biomass and litterfall of Pinus pumila scrubs growing on the Kiso mountain range in central Japan
Authors: Kajimoto Takuya
Published: March 2006

Aboveground biomass and litterfall of Pinus pumila scrubs, growing on the Kiso mountain range in central Japan, were investigated from 1984 to 1985. The biomass of two research plots (P1 and P2) with different scrub heights was estimated by two methods, the stratified clip technique and the allometric method. Aboveground total biomass estimated by the latter method reached 181 ton d.w. ha−1 in P1 and 132 ton d.w. ha−1 in P2. Creeping stems contributed to about half of the total biomass. Although estimates of woody organs differed between the two plots, leaf biomass estimates were almost the same at 15.5 ton d.w. ha−1. The canopies of the two P. pumila scrubs were characterized by a large mean leaf area density of 5.0 m2 m−3. Despite this large area density, relatively moderate attenuation of light intensity was observed. Specific leaf area generally increased with reduced leaf height. Annual total litterfall was estimated to be 3.60 ton d.w. ha−1 yr−1 in P1 and 2.39 ton d.w. ha−1 yr−1 in P2. Annual leaf fall in both plots was approximately 2.0 ton d.w. ha−1 yr−1. Leaves fell mainly in early autumn. Annual loss rates of branches, estimated as the sum of annual branch litterfall and the amount of newly formed attached dead branches, were 0.29 ton d.w. ha−1 yr−1 in P1 and 0.37 ton d.w. ha−1 yr−1 in P2.
Studies on the dynamic properties of terrestrial ecosystems based on a simulation model II. Tropical rainforest dynamics and stability as influenced by stem mortality
Authors: Oikawa Takehisa
Published: March 2006

Further analysis of tropical rainforest dynamics and stability in relation to stem mortality has been conducted using a microcomputer model developed in a previous study (Oikawa, 1985).

By simulation experiments covering a period of 100 years, the effects of changing stem mortality (δc) upon a tropical rainforest were investigated. Increasing stem mortality ranging from a standard value (3%yr−1) to a 4‐fold value (12%yr−1) brings about decreases in stem biomass and thus total living biomass, and a contrasting increase of stem litterfall flux at the steady state of the forest ecosystem. At the same time, the decreased stem biomass at the steady state is predicted to result in increases of gross production (Pg) and net production (Pn), and an improvement in production efficiency of the model rainforest expressed as the Pn/Pg ratio.

similar simulation experiments predict that the improved production efficiency in the forest with a 4‐fold stem mortality is able to enhance tolerance to less productive environments such as a prolonged dry season or a reduced incident light flux density. On the other hand, the standard stem mortality (δc=3%yr−1), which was estimated as a probable value for the Pasoh forest, West Malaysia, is considered to approximate the lower threshold necessary for attaining forest stability.

Based on the results obtained, the significance of δc for the dynamics and stability of a tropical rainforest ecosystem is discussed in relation to the competition and tolerance of trees. In addition, the effectiveness of the simulation approach adopted here is emphasized.
Gradual increase in the number of Asphondylia aucubae (Diptera, Cecidomyiidae) due to inversely density‐dependent mortality processes
Authors: Ohsaki Naota , Yukawa Junichi
Published: March 2006

The population dynamics of the aucuba fruit midge, Asphondylia aucubae (Japanese name: Aokimitamabae), were studied for 3 yr mainly at a broad‐leaved evergreen forest on Mt. Shiroyama in Kagoshima City. This species is univoltine and adults emerge in May. Eggs were laid randomly inside the immature fruit of the host plant, Aucuba japonica (Japanese name: Aoki). Healthy fruit fell by the following March, whereas galled fruit remained on the trees even after the emergence of adult midges. The survival rate from the egg to adult stage was estimated to be 24.2%, and the number of midges on five census trees increased gradually during the census period. Two important mortality factors were recognized, i.e., fall of incompletely galled fruit and damage of the galled fruit by feeding of caterpillars of a moth. Some unknown factors were also found to be important, operating in an inversely density‐dependent manner. The gradual increase of A. aucubae is considered to be caused by such inversely density‐dependent mortality processes.
Plant form analysis based on the pipe model theory I. A statical model within the crown
Authors: Chiba Yukihiro
Published: March 2006

Extending Oohata and Shinozaki's statical model, a quantitative description of crown/canopy structure is presented. According to this model, the amount of non‐photosynthetic organs in a given horizontal layer can be regarded as supporting the total plant weight above that layer. Within the crown, however, only stems, not branches, support it. In fact, the total amount of a community above a given horizon and the stem density at that horizon are found to be directly proportional, not only in forest stands and glassland communities but also in single trees. This means that the statical model should hold even within the crown/canopy range as well as the leafless range. The present analysis suggests that the crown structure of terrestrial plants is closely correlated with the pattern of branching for optimal use of sunlight. However, linearity of these relationships cannot always be obtained, perhaps due to variation in the branching pattern of trees.
Holocene sedimentary history of some coastal plains in Hokkaido, Japan IV. Diatom assemblages in the sediments from Kushiro moor (2)
Authors: Kumano Shigeru , Ihira Masashi , Maeda Yasuo , Yamauchi Misako , Matsumoto Eiji , Matsuda Isao
Published: March 2006

Diatom assemblages of sediments obtained from three sites on Kushiro Moor were analyzed to investigate the Holocene sedimentary history. The results showed that: 1) The Takkobu site was originally at the bottom of the paleo‐Kushiro Bay, and after‐wards the paleo‐Takkobu Lagoon developed, became sealed off, and changed to a freshwater lake. The succession to peat moor probably began about 2000 yr B.P. at the Takkobu site. 2) The Tsurui site was originally at the bottom of the paleo‐Kushiro Bay, then changed to the paleo‐Kushiro Lagoon and became peat moor as a result of the first Holocene regression, which finished about 3600 yr B.P. The site then returned to a brackish lake again, probably due to the second Holocene transgression between 3600 and 3000 yr B.P., thereafter passing through brackish lake and freshwater lake stages, and eventually becaming peat moor at about 2000 yr B.P., 3) At the Chuo site, the second paleo‐Kushiro Bay developed again as a result of the second Holocene transgression, which finished about 3000 yr B.P. Thereafter, brackish or freshwater lakes, rivers, and then peat moor developed in the central area of Kushiro Moor. 4) The second marine diatom zone (MD2Zone), which indicates the second Holocene transgression, complete by about 3000 yr B.P., is detected only at the Chuo site in the central area of Kushiro Moor.
Effects of water level fluctuation on the growth of Nelumbo nucifera Gaertn. in Lake Kasumigaura, Japan
Authors: Nohara Seiichi , Tsuchiya Takayoshi
Published: March 2006

Investigations were made of the growth of Nelumbo nucifera, an aquatic higher plant, in a natural stand in Lake Kasumigaura. A rise of 1.0 m in the water level after a typhoon in August 1986 caused a subsequent decrease in biomass of N. nucifera from the maximum of 291 g d.w. m−2 in July to a minimum of 75 g d.w. m−2. The biomass recovered thereafter in shallower regions. The underground biomass in October tended to increase toward the shore. The total leaf area index (LAI) is the sum of LAI of floating leaves and emergent leaves. The maximum total LAI was 1.3 and 2.8 m2 m−2 in 1986 and 1987, respectively. LAI of floating leaves did not exceed 1 m2 m−2. The elongation rates of the petiole of floating and emergent leaves just after unrolling were 2.6 and 3.4 cm day−1, respectively. The sudden rise in water level (25 cm day−1) after the typhoon in August 1986 caused drowning and subsequent decomposition of the mature leaves. Only the young leaves were able to elongate, allowing their laminae to reach the water surface. The fluctuation in water level, characterized by the amplitude and duration of flooding and the time of flooding in the life cycle, is an important factor determining the growth and survival of N. nucifera in Lake Kasumigaura.
Photosynthesis and respiration of Pinus pumila needles in relation to needle age and season
Authors: Kajimoto Takuya
Published: March 2006

Rates of net photosynthesis and dark respiration were measured for detached needles of Pinus pumila trees growing on the Kiso mountain range in central Japan in 1987. Dependency of photosynthesis on light and temperature was examined in relation to needle age and season. The light saturation point of net photosynthesis was lower in 3‐ and 4‐yr‐old needles than that in current (flushed in 1987), 1‐ and 2‐yr‐old needles. Pnmax, net photosynthetic rates at 1000 μmol m−2 s−1 and 15°C, of needles from 1‐ to 4‐yr‐old generally decreased with needle age. Pnmax of 1‐ to 4‐yr‐old needles became higher in August than in other months, and Pnmax of current needles did so in September. Current needles showed high respiration rates (at 15°C) only in August. Optimum air temperatures for net photosynthesis at 1000 μmol m−2 s−1 were between 10 and 15°C for current and 1‐yr‐old needles. The temperature coefficient of dark respiration rates was 2.3–3.3 for current needles from August to October, and 2.2 for 1‐yr‐old needles in mid‐July.
Evolution of airborne infectious diseases according to changes in characteristics of the host population
Authors: Kakehashi Masayuki , Yoshinaga Fumitaka
Published: March 2006

The authors predicted evolutionary changes in airborne infectious diseases according to changes in the characteristics of the host population. The predictions were based upon a mathematical model of infectious diseases and the validity of the predictions was verified against the history of man and pathogens. The feature of this model is that it involves a density of pathogens in the environment as an additional variable which can be regarded as more suitable to airborne infectious diseases. In spite of this modification, this study reached a similar conclusion to the threshold density theory: that is, susceptible host density in the absence of the pathogen must be larger than that in the presence of the pathogen, for the pathogen to be persistent. Moreover the authors concluded that one type of pathogen cannot be replaced by another type of pathogen as long as the susceptible host density of the former type is the mininum one. The predictions were considered to be valid for a wide range of infectous diseases. Making use of these principles, the authors predicted that the variety of infectious diseases should increase as host density increases and that pathogens should evolve to be less virulent as the host life‐span increases. The finalidea discussed is whether or nor the history of man and pathogen can be verified by the predictions.
Survivorship of a monocarpic bamboo grass, Sasa kurilensis, during the early regeneration process after mass flowering
Authors: Makita Akifumi
Published: March 2006

The survivorship of a monocarpic bamboo grass, Sasa kurilensis, during the early regeneration process was documented by a 10 year observation of the seedling population after mass flowering in the Hakkoda Mountains, northern Japan. Three phases were recognized: the establishment, density‐stable and thinning phases. The mortality of the densely germinated seedlings (932.9m−2 in a Betula ermanii forest and 1222.3 m−2 in a Sasa grassland) was high, up to 0.5 year−1, in the establishment phase (0–1 year after germination) and low in the density‐stable phase (1–3 years after germination). After reaching full density state, the seedling population showed a nearly constant mortality of 0.18 year−1 due to self‐thinning (the thinning phase). The high C/F ratio presumably caused suppressed seedlings to die. Recovery of the S. kurilensis population was estimated to require ca 20 years in the study plots, judging from the height growth and the decrease in culm density of the seedling population. The illuminance on the ground was higher in the flowered population than in the unflowered one for 5 years after mass death. The duration of high ground illuminance is an important factor affecting the dynamics of forests with Sasa undergrowth, because tree seedlings need to establish under high ground illuminance for the successful regeneration of the forests.
Enclosure experiment on the control mechanism of planktonic bacterial standing stock
Authors: Kato Kenji , Oh Su‐wan , Yamamoto Hiroyuki , Hanazato Takayuki , Yasuda Ikuko , Otuki Akira , Takahashi Masayuki
Published: March 2006

In order to understand the control mechanisms of a large, stable bacterial standing stock, enclosure experiments were conducted in a eutrophic lake, where both bacterial productivity and grazing pressure were very high. Total bacterial number in the different enclosures ranged from 1.2 to 2.7×107 cells mL−1 throughout the experiment. The average bacterial cell production rate estimated from a grazer eliminating experiment was 6.3×105 cells mL−1 h−1. Difference in the bacterial cell production rate between shaded and unshaded enclosures was not apparent. Bacteria showed a reduction in standing stock of only about 25–30% even after the supply of light was cut to 1%. Bacteria in the shaded enclosures then recovered their production rate in the first 12 days of perturbation. Grazing pressure in the shaded enclosures was not less than that for the control. Thus, it was considered a control mechanism of bacterial stable standing stock that the bacteria shifted their organic substrate from extracellular dissolved organic carbon freshly released from phytoplankton to that already stocked in the water column, though it is not known whether the dominant bacteria were the same.
Female mate preference and offspring fitness in the melon fly
Authors: Kasuya Eiiti
Published: March 2006

The influence of female mate preference on the fitness components of offspring was studied in the melon fly, Dacus cucurbitae. Adult flies were allowed to mate under two experimental treatments. In one treatment, 100 females and 100 males were allowed to mate freely in a cage (cage‐mating). In the other treatment, a single female was allowed to mate with a single male in a small chamber (chamber‐mating). Viability in the immature stages was not different between two treatments. The developmental speed of female offspring in the cage‐mating treatment was faster than that in the chamber‐mating treatment. The wing length of offspring of both sex in the cage‐mating treatment was also larger than that in the chamber‐mating treatment. These results were considered to support 3‐trait handicap models of the evolution of female mate preference.
Factors affecting individual variation in resting site fidelity in the patellid limpet, Cellana toreuma (Reeve)
Authors: Iwasaki Keiji
Published: March 2006

An investigation was made of individual variation in resting site fidelity in the limpet, Cellana toreuma, with special attention to the adaptiveness of its homing behaviour. Limpets resting in the higher part of the study site showed strong resting site fidelity while those in the middle part showed weaker fidelity and tended to shift their resting sites to higher parts. Limpets resting in the lower part where there were an abundant supply of food and high predation intensity, had the strongest resting site fidelity and always returned to fixed resting sites with mucous sheets. The resting site fidelity varied continuously among individuals. Four causes for shift of resting site were detected: fleeing from starfish, Coscinasterias acutispina, pushing contests for resting site, non‐returning excursions following and without following other's trail. The frequency of shift of resting sites due to each of these causes varied among individuals. Estimation of energy budget during about half a month showed that the location of resting site and frequency of shift of the site considerably affected the growth of limpets through energy expenditure by respiration and stationary mucus secretion, and energy intake by foraging. These variations were proposed as being a result not of density dependent dispersal nor adaptation to a single factor such as desiccation, heavy wave impacts or predation, but being due to individual difference in a compromise between two conflicting factors, susceptibility to predation and accessibility to food resources.
High SO2 resistance of Clethra barbinervis established in a smoke‐polluted area of Ashio, Tochigi Prefecture, Japan
Authors: Ikeda Hiroaki , Natori Toshiki , Totsuka Tsumugu , Iwaki Hideo
Published: March 2006

The effect of SO2 on the photosynthesis of Clethra barbinervis collected from a smoke‐polluted area near the Ashio copper smelter in Tochigi Prefecture was compared with C. barbinervis collected from a nonpolluted district in Tsukuba, Ibaraki Prefecture and Quercus mongolica var. grosseserrata grown in a nonpolluted field in Nagano Prefecture. The plants were exposed to 0.5–1.5 p.p.m. SO2 for 90 min (short‐term) and to 0.3 p.p.m. SO2 for 31–39 days (long‐term). The Clethra plants from both sites had a lower intrinsic stomatal conductance and photosynthetic rate than Quercus plants. Short‐and long‐term fumigation caused stomatal closure in Quercus plants, but had little effect on the stomatal conductance of Clethra plants. Under short‐term fumigation, nonstomatal photosynthetic inhibition per unit of absorbed SO2 was smallest in Clethra plants from Ashio. Long‐term fumigation caused photosynthetic decline and visible foliar injury to Quercus plants, but had no effect on Clethra plants from Ashio. Consequently, Clethra plants from Ashio had a higher photosynthetic rate than Quercus plants after long‐term fumigation. These results suggest that C. barbinervis populations in the smoke‐polluted area of Ashio had evolved high SO2 resistance connected with SO2 detoxification ability in mesophyll cells.
Vegetation history since the last glacial period in the Mikata lowland, the Sea of Japan area, western Japan
Authors: Takahara Hikaru , Takeoka Masaji
Published: March 2006

Local and regional vegetation since the last glacial period was reconstructed on the basis of a palynological study of sediment at Iwaya, in the Sea of Japan area, western Japan. During the interstade (before about 30 000 years BP), forests were composed predominantly of Cryptomeria japonica with Tsuga sieboldii and cool‐temperate deciduous broad‐leaved trees. In the pre‐full‐glacial, the full‐glacial and the early late‐glacial (30 000‐12 000 years BP), forests were dominated by temperate (montane) and boreal (subalpine) Pinaceae and Betula. During the early full‐glacial, the pinaceous forests were mixed with cool‐temperate trees such as Fagus crenata. In the late full‐glacial (18 000‐16 000 years BP), the maximum development of pinaceous conifer forests was recognized. Cool‐temperate broad‐leaved forests composed mainly of F. crenata and Quercus (Lepidobalanus) replaced the pinaceous forests at about 12 000 years BP and were maintained to the early postglacial. Cryptomeria japonica was distributed around the Mikata lowland during the last glacial. Cryptomeria japonica, which began to increase at 16 000 years BP, increased abruptly in the early postglacial and spread throughout the postglacial in the lowlands. After 6300 years BP, lucidophyllous forests composed mainly of Quercus (Cyclobalanopsis) and Castanopsis were established in the Mikata district; this was later than in the inland and the Pacific Ocean areas in the Kinki region, western Japan. In historic times (after ca 2000 years BP), secondary forest of Pinus densiflora, which can grow as a pioneer in disturbed habitats, spread.
Distribution pattern and age structure of Abies firma saplings in a mature mixed forest of A. firma and Fagus japonica
Authors: Agetsuma Naoki
Published: March 2006

Age and spatial distribution of Abies firma saplings were analyzed in a mature mixed forest of A. firma and Fagus japonica. There were two major peaks in the age structure of Abies saplings at around 10 and 75 years of age. Distribution of these age classes of saplings was contagious, while that of all saplings was approximately random. These facts showed that most of the establishment of A. firma occurs just after a gap is formed, and the frequency at which such establishment occurs is about once every 60 years in a 1600 m2 area.
Responses of photosynthesis, leaf conductance and growth to different salinities in three coastal dune plants
Authors: Ishikawa Shin‐ichi , Oikawa Takehisa , Furukawa Akio
Published: March 2006

The effects of soil‐water salinity on growth and photosynthesis of three coastal dune plants were examined by salt‐treatment in order to clarify the causal relationship between salinity and plant distribution in a dune habitat. Plants were cultivated hydroponically at three salinity levels: 0, 10 and 100 mM NaCl. With the 100 mM salt treatment, Calystegia soldanella (C3 species) had the highest relative growth rate (RGR) (0.085 g g−1 d−1), followed by Carex kobomugi (C3) (0.066), and Ischaemum anthephoroides (C4) (0.060). This order coincides with the distribution pattern of the three species on coastal dunes;Calystegia soldanella is generally distributed in more seaward areas whereas I. anthephoroides occurs further inland. The order of RGR was determined exclusively by leaf area ratio (LAR) among the three species. Due to its C4 pathway, I. anthephoroides had higher net photosynthetic rate (Pn) and net assimilation rate (NAR) than the two C3 plants at all NaCl concentrations, despite its low RGR. This apparent discrepancy is explainable by differences of LAR among the three species; LAR of I. anthephoroides was lowest, and about half that of Calystegia soldanella. These results suggest that LAR is one of the main determinants of salt tolerance based on RGR, whereas Pn or NAR may not be significant.
Land‐use selection by dandelions in the Tokyo metropolitan area, Japan
Authors: Ogawa Kiyoshi , Mototani Isao
Published: March 2006

Land use by native and introduced dandelion groups in man‐made habitats was studied at 7090 survey points in the Tokyo metropolitan area, Japan, in order to clarify the replacement phenomenon occurring among dandelions. In the center of Tokyo, where the native group was rare, the percentage occurrence of the introduced group was lower than in other regions, whereas in the outskirts of Tokyo, both groups showed much higher occurrence. Roadsides, vacant areas and urban land‐use categories were significantly favorable for growth of the introduced group, whereas preserved or rural land use was more favorable for the native group. Seed fertility in the introduced group was more than 80%, and was independent of population size, whereas in the native group it was not as high, and for a small population was dependent on population size, being stable at about 70% in populations larger than 70 plants. Thus, both large populations and solitary plants in the introduced group appeared to act as seed sources, making it likely that the introduced group will spread increasingly through roadsides and urban land, which are becoming more widespread as a result of urbanization. It is feared that, unless deliberately retained, the amount of preserved or rural land which has fostered large populations of the native group will further decrease with urbanization and other forms of development, thus depleting the seed sources and reducing the population.
Effect of flooding‐drawdown cycle on vegetation in a system of floating peat mat and pond
Authors: Haraguchi Akira
Published: March 2006

The relationship between vegetation and seasonal changes in water level was examined in a system of terrestrializing floating peat mat and pond in a warm temperate zone. The duration of flooding, or drawdown period, is related to vegetation in the mat. The first process of terrestrialization would be the attenuation of floating‐sinking movement of the mat and the consequent stabilization of water level. Water level at the time when the movement of the mat was attenuated determined the subsequent vegetation change at the site. Two series of succession according to terrestrialization were recognized, and started from initial conditions of low and high water levels respectively. Habitats in low initial water levels experienced short flooding and long drawdown periods. Species changes in the successional series were:Menyanthes trifoliata‐Rhynchospora fauriei‐Eriocaulon sikokianum‐Sphagnum cuspidatum. Submerged peat was experimentally emerged, and the crowded community of Rhynchospora fauriei and Eriocaulon sikokianum established within one or two years. Appearance of these species was controlled by the water level of the habitats in winter. Another series of species changes in terrestrialization process was:Menyanthes trifoliata‐Phragmites australis‐Carex thunbergii or Isachne globosa. Habitats of these types of vegetation were in the area with relatively high initial water level (long flooding and short drawdown) when the floating‐sinking movement of the mat attenuated. After the temporal paludification, the water level was lowered by the accumulation of peat in the process of terrestrialization.
Influence of livestock grazing on vegetation in a saline area in Northeast Thailand
Authors: Nemoto Masayuki , Panchaban Santibhab
Published: March 2006

The influence of grazing by water buffalo (Bubalas bufalis) and cattle (Bos taurus) was estimated for vegetation inside and outside cages in a saline area at Khon Kaen, Northeast Thailand.

The home range of water buffalo and cattle shifted in response to the period of rice cultivation: during the rice‐growing season these animals grazed on roadsides and abandoned places such as the study area; after rice harvest they grazed mainly rice stubble on the paddy.

The vegetation in the study area was divided into three types: 1) dominated by the annual grasses Chloris barbata and Ischaemum rugosum; vegetational cover and plant height in the cage increase due to the increase of these grasses; 2) thorny shrub patch of Maytenus mekongensis; other species in this patch almost died a year after experimental elimination of this shrub; this salt‐tolerant shrub not only protected the co‐existing species from grazing, but also suppressed salt accumulation; 3) almost pure stand of Panicum repens; livestock preferred this perennial grass over others.

Electrical conductivity (EC) of surface soil did not increase under the vegetation protected from grazing. Litter and other organic matter in the soil suppressed the upward movement of brine. Grazing led to an increase of bare ground where NaCl accumulated, and modified the heterogeneity of vegetation, which was reflected in the degree of salt accumulation.
Succession of sessile organisms on experimental plates immersed in Nabeta Bay, Izu Peninsula, Japan IV. Temporal changes in metabolism, biomass and maturity of community
Authors: Hirata Tetsu
Published: March 2006

Community succession in the metabolism, biomass and maturity of sessile organisms on concrete plates immersed at depths of 1.0, 2.5, 4.0 and 5.5 m in Nabeta Bay, Shimoda, pacific coast of Japan, was investigated over a period of about 3 yr. Gross primary production of the community (Pg) and community respiration (R) showed maxima at 10 and 13 months after immersion, and then Pg decreased significantly at all depths, whereas R was reduced only at the lower two depths. A parameter of community biomass, chlorophyll a (Chl. a), showed a similar successional change to Pg. Five other parameters, i.e. dry mass (DM), ash dry mass (ADM), ash‐free dry mass (AFDM), organic carbon (C) and organic nitrogen (N) increased significantly throughout succession, at least at the uppermost depth, but decreased significantly in the period 13–37 months after immersion at the lowest depth. Successional changes in five indices reflecting community maturity, i.e. the ratios of estimated daily gross primary production/estimated daily respiration (Pg/R), gross primary production/organic carbon (Pg/C), gross primary production/chlorophyll a (Pg/Chl. a), organic carbon/organic nitrogen (C/N) and Margalef's pigment diversity (D430/D665), also differed among the depths, especially at 37 months after immersion. Succession at the upper two depths appeared to progress toward a mature state, as opposed to retrogression to an immature state at the lower two depths. This difference in successional changes in these 13 parameters between depths agrees with the prediction of Margalef (1968) and Odum (1969), despite the tendency for Pg/R to be more heterotrophic in an open system.
Systems analysis of density‐dependent population processes in the azuki bean weevil, Callosobruchus chinensis
Authors: Shimada Masakazu
Published: March 2006

Systems analysis of density‐dependent population processes was conducted in an experimental population of the azuki bean weevil, Callosobruchus chinensis. Density‐dependent population change was formulated for two separate processes; adult production of eggs and hatching of the eggs outside the beans, and survival of the first instar larvae inside the beans and their emergence as new adults. The formulation of each process was based on a common basic equation modified from the logistic‐difference equation. Parametric values were estimated from experimental data on C. chinensis in a laboratory population.

Simulations of the model showed good fits not only to observed population changes both outside and inside the beans, but also to the observed reproduction curve reflecting the population change as a whole within one generation in an experimental population.

Furthermore, population dynamics from generation to generation were simulated from the model reproduction curve. The simulation showed a slight dumped oscillation and converged to a carrying capacity, which fitted well with the experimental population dynamics.
Growth and biomass turnover of Hydrocharis dubia L. cultured under different nutrient conditions
Authors: Tsuchiya Takayoshi
Published: March 2006

Growth of a floating‐leaved plant, Hydrocharis dubia L., was examined under varying nutrient conditions between 0.3 and 30 mgN l−1 total inorganic nitrogen. H. dubia plants cultured under the most nutrient‐rich condition showed the highest maximum ramet density (736 m−2), the highest maximum biomass (80.4 g dry weight m−2), and the highest total net production (185 g dry weight m−2 in 82 days). Plants under nutrient‐poor conditions had a relatively large proportion of root biomass and a small proportion of leaves with a long life span.

Compared with other floating‐leaved and terrestrial plants, the maximum biomass of H. dubia was relatively small. This, and the rapid biomass turnover, was related to the short life span of leaves (13.2–18.7 days) and large biomass distribution to leaves.
Buried seed populations on the volcano Mt. Usu, northern Japan, ten years after the 1977–78 eruptions
Authors: Tsuyuzaki Shiro
Published: March 2006

In 1987, a study on buried seed populations was conducted in the crater basin of Mt. Usu, a volcano located in northern Japan, where the vegetation had beeen almost completely destroyed by eruptions in 1977 and 1978. The former vegetation had consisted of grassland and broad‐leaved forest. In the areas formerly occupied by this grassland and forest, 2128.0 and 1985.3 seeds per square meter, respectively, were extracted from 12 blocks of the former topsoil using a floattion method. This revealed that many seeds were still viable even after ten years of burial under thick volcanic deposits. The seeds were distributed more in sandy soil than in rocky soil of the former topsoil. Twenty‐five species, most of which favored grassland, were detected in both the former grassland and forest. From comparison of α‐and β‐diversities between the grassland and forest, the structure of the buried seed population was considered likely to have been more diverse in the forest than in the grassland. The determinants of composition of the buried seed populations were discussed with reference to the former vegetation and soil characteristics.
Ecological studies on the plants of fagaceae V. Growth in the sapling stage and minimal participation of reserve materials in the formation of annual new shoots of the evergreen Quercus glauca thunb
Authors: Matsubara Teruo , Hiroki Shozo
Published: March 2006

The growth in the sapling stage and participation of reserve materials in the formation of annual new shoots were studied in the evergreen tree Quercus glauca. The growth and some allometric relationship were analyzed for 1‐to 4‐year‐old Q. glauca plants. Each individual was felled at the foot, or all the leaves were removed at the end of the growth season (December). Sprouts were formed on the remaining stump and new shoots were formed from winter buds under dark or light conditions. The dry weight of each plant part was measured before and afte,, the formation of these new shoots. The amount of reserve materials in each plant part was estimated from the difference in allometric relatationships before and after the formation of new shoots. Although the results showed that a small amount of reserve material existed in roots, the participation of reserve materials in the formation of annual new shoots was negligible in Q. glauca growing under usual conditions, and substrates for the formation of new shoots were derived from the products of photosynthesis in old leaves and developing new leaves. Some of the growth characteristics of Q. glauca were compared with those of the deciduous species Quercus variabilis to explain ecological behavior of the two species in warmtemperate secondary forests.
Effect of light interception by non‐photosynthetic organs on canopy photosynthetic production
Authors: Kurachi Nahoko , Hagihara Akio , Hozumi Kazuo
Published: March 2006

A canopy photosynthesis model was derived on the assumption that the light diminution within a canopy is caused by both leaves and non‐photosynthetic organs. The light diminution by leaves and that by non‐photosynthetic organs were taken into account separately in the Lambert‐Beer equation of light extinction. The light flux density on the leaf surface at each depth was evaluated from the leaf's share of light. The light flux density on the leaf surface thus obtained was incorporated into the Monsi‐Saeki model of canopy photosynthesis. The proposed model was applied for estimating gross canopy photosynthesis in a 19‐year‐old Larix leptolepis plantation where 38% of the light diminution was due to non‐photosynthetic organs. The daily canopy photosynthesis on one summer day calculated using the present model was about 22% less than that calculated by the conventional Monsi‐Saeki model, in which light interception by non‐photosynthetic organs is neglected. The degree of such reduction in canopy photosynthesis through shading by non‐photosynthetic organs was assessed in relation to parameters affecting light extinction, leaf photosynthetic characteristics, and light regime above the canopy.
Food preferences and nematode parasitism in mycophagous Drosophila
Authors: Kimura Masahito T. , Toda Masanori J.
Published: March 2006

Food preferences and nematode parasitism were studied in natural populations of mycophagous Drosophila in and near Sapporo, northern Japan. Species which preferred fresh mushrooms showed species‐specific responses to Pleurotus mushrooms:D. pirka bred only on Pleurotus cornucopiae, D. trivitata on P. cornucopiae and P. ostreatus, D. trilineata on these two Pleurotus mushrooms and some other mushrooms, while D. sexvittata bred on a wide variety of mushrooms but seldom on Pleurotus mushrooms. Species which preferred decayed mushrooms (D. quadrivittata, D. histrioides, D. testacea and species of the quinaria species‐group) showed host preferences different from those of the above species. The rate of parasitism by nematodes was generally higher in species which prefer decayed mushrooms than in species which prefer fresh mushrooms. Among species which prefer fresh mushrooms, only D. trilineata was parasitized frequently by nematodes. It was not clear what factors determine the rate of parasitism in these mycophagous Drosophila.

D. pirka, D. trivittata and D. trilineata passed through three or four generations per year and entered reproductive diapause in early September in and near Sapporo.