Rice (Oryza sativa L.) quality and yield are degraded by high temperature, especially at the ripe... more Rice (Oryza sativa L.) quality and yield are degraded by high temperature, especially at the ripening stage after the heading of panicles. The effect is lethal when the panicle temperature (T p ) is excessively high; therefore, maintaining a low T p is important to avoid deleterious impacts on the grains. Microclimatic factors and plant physiological elements determine the T p . One determining factor is the color (or reflectance) of spikelets that constitute the panicle because it determines the absorption of shortwave radiation energy. An additional factor is the panicle position because it influences heat exchange by the wind and input energy from downward shortwave radiation. In this study, inter-strain differences in spikelet color and panicle height at heading were assessed. The T p of strains differing in panicle color and panicle height were measured with thermocouples. In addition, to estimate the effect of each trait, we adopted a micrometeorological model. Panicle color was quantified using a hyperspectral sensor. Combining the spectral reflectance and spectral radiation, we assessed the effect of panicle color on T p . The differences in panicle color and panicle position significantly affected T p . The strain with a dark panicle had a maximum measured T p about 1.8 °C higher than that of the strain with a light-colored panicle. The T p of a strain with panicles at higher positions was up to 2.0 °C higher than that of a strain with panicles at lower positions. These relationships were consistent with the model estimates. When shortwave radiation was strong, the difference in T p between strains showed a positive correlation, suggesting that the temperature difference was associated with shortwave radiation. Therefore, we concluded that rice strains with a brighter panicle color and low panicle position are less prone to deleterious impacts of high temperature because net radiation is reduced.
Nitrogen is often limiting nutrient for plant growth and is mainly supplied from atmosphere. Fore... more Nitrogen is often limiting nutrient for plant growth and is mainly supplied from atmosphere. Forests can act as a filter for atmospherically deposited nitrogen and maintain background concentration levels of nitrogen in streams. However, recent increases in atmospheric nitrogen deposition have resulted in a shift from net-nitrogen retention to high levels of net-nitrogen loss from forested, resulting in high nitrogen concentration stream water. In the Tatara River Basin, Fukuoka City, nitrogen retention capacity of upland forests has decreased and nitrate concentrations in downstream water have been increasing (Chiwa et al., 2012). This study analyzed NO 3-δN, NO3-δ18O in addition to NO3 concentrations in stream water in the Tatara River Basin to assess the impact of nitrogen saturation forest on downstream water quality. In northern part of the basin, NO 3 concentrations of upstream were lower than downstream. In contrast, in southern part of the basin, NO3 concentrations in upstre...
Plants have evolved and grown under the selection pressure of gravitational force at 1 g on Earth... more Plants have evolved and grown under the selection pressure of gravitational force at 1 g on Earth. In response to this selection pressure, plants have acquired gravitropism to sense gravity and change their growth direction. In addition, plants also adjust their morphogenesis in response to different gravitational forces in a phenomenon known as gravity resistance. However, the gravity resistance phenomenon in plants is poorly understood due to the prevalence of 1 g gravitational force on Earth: not only it is difficult to culture plants at gravity > 1 g(hypergravity) for a long period of time but it is also impossible to create a < 1 genvironment (μg, micro g) on Earth without specialized facilities. Despite these technical challenges, it is important to understand how plants grow in different gravity conditions in order to understand land plant adaptation to the 1 g environment or for outer space exploration. To address this, we have developed a centrifugal device for a prolonged duration of plant culture in hypergravity conditions, and a project to grow plants under the μg environment in the International Space Station is also underway. Our plant material of choice is Physcomitrium (Physcomitrella) patens, one of the pioneer plants on land and a model bryophyte often used in plant biology. In this review, we summarize our latest findings regarding P. patens growth response to hypergravity, with reference to our on-going "Space moss" project. In our ground-based hypergravity experiments, we analyzed the morphological and physiological changes and found unexpected increments of chloroplast size and photosynthesis rate, which might underlie the enhancement of growth and increase in the number of gametophores and rhizoids. We further discussed our approaches at the cellular level and compare the gravity resistance in mosses and that in angiosperms. Finally, we highlight the advantages and perspectives from the space experiments and conclude that research with bryophytes is beneficial to comprehensively and precisely understand gravitational responses in plants.
Клучни зборови: ѕидно сликарство, пигменти, хемиски анализи Апстракт: Во трудот се презентирани р... more Клучни зборови: ѕидно сликарство, пигменти, хемиски анализи Апстракт: Во трудот се презентирани резулатите произлезени од хемиските истражувања на ѕидното сликарство во црквата Св. Никола во Топличкиот манастир, со акцент на анализите насочени кон карактеризација на сликарската палета и применетата сликарска техника. Експерименталните истражувања се засновани на хемиски анализи на голем број примероци земени од различни позиции на живописот во наосот, во припратата и во северниот параклис. Во аналитичкиот дел се презентирани резултатите од извршените анализи за одредување на хемискиот состав на пигментите и врзивниот медиум, со примена на Micro-Raman, FTIR и XRF, како и прикази кои ја одразуваат микро-стратиграфската структура на живописот. Аналитичките сознанија поврзани со сликарската палета и техника придонесоа во потврдувањето на авторството на зографот Јован од Грамоста, укажувајќи дека овој зограф кој се потпишал во припратата, го насликал и наосот со олтарскиот простор, како и северниот параклис. Исто така, аналитичките сознанија помогнаа околу атрибуција на авторството, но и попрецизно одредување на временските рамки во кои настанал првобитниот слој живопис од западниот ѕид на наосот.
The article Why is chlorophyll b only used in light-harvesting systems?, written by Atsushi Kume,... more The article Why is chlorophyll b only used in light-harvesting systems?, written by Atsushi Kume, Tomoko Akitsu, Kenio Nishida Nasahara, was originally published electronically on the publisher's internet portal (currently Springer-Link) on 10 July 2018 without open access.
In 2016, Ecological Research (ER) celebrated its 30th anniversary. ER's goal is to be the leading... more In 2016, Ecological Research (ER) celebrated its 30th anniversary. ER's goal is to be the leading ecological, evolutionary, and biodiversity journal in Asia. This article introduces the development of ER, improvements to its editorial system and their outcomes, and the strategies designed to achieve this goal. ER has already become a leading comprehensive and international publication as shown by statistical evidence and its strong editorial foundation. However, some members of the Ecological Society of Japan (ESJ) retain impressions of an old stereotype about ER. The discrepancy between the current status of the journal and its stereotype may explain why submissions from Japan remain static. A new article category for ER, Biodiversity in Asia, was created to encourage Asian studies. In addition, the Forum category is dedicated to promoting a broad understanding of the ESJ's various activities. To promote open science, the proportion of open access articles in the journal is increasing. The publication of Data papers has been accelerated to improve the public availability of excellent open data sets. ER symposia and seminars provide good opportunities for members to participate. ER financially supports the invitation of scientists internationally to facilitate research exchanges with other countries and consequently promotes the internationalization of the ESJ. The ESJ is open to the world's ecologists, and your participation in developing ER is welcome.
We measured and compared the d 13 C values and nitrogen concentrations within the photosynthetic ... more We measured and compared the d 13 C values and nitrogen concentrations within the photosynthetic parts (Np) of phototrophs growing in different successional stages and different soil conditions at Ny-A ˚lesund, Svalbard, Norway. At all study sites, the Np value of vascular plants ranged from 1.0 to 2.2%. The Np value for most moss species was less than 1.0%; values for lichens were about 0.5%. No significant correlation was detected between Np and d 13 C; however, different plant species occupied distinct fields on a d 13 CeNp plot, with minimal overlap between species. The Np value of Saxifraga oppositifolia, which grew at all of the study sites, ranged from 1.1 to 1.5%. Differences in growth form had no effect on Np. The Np and d 13 C values obtained for S. oppositifolia were confined to within a narrow range regardless of site conditions.
Respiration of the belowground parts of vascular plants: its contribution to total soil respirati... more Respiration of the belowground parts of vascular plants: its contribution to total soil respiration on a successional glacier foreland in Ny-Alesund, Svalbard.
The Arctic terrestrial ecosystem is thought to be extremely susceptible to climate change. Howeve... more The Arctic terrestrial ecosystem is thought to be extremely susceptible to climate change. However, because of the diverse responses of ecosystem components to change, an overall response of the ecosystem carbon cycle to climate change is still hard to predict. In this review, we focus on several recent studies conducted to clarify the pattern of the carbon cycle on the deglaciated area of Ny-Alesund, Svalbard in the high Arctic. Vegetation cover and soil carbon pools tended to increase with the progress of succession. However, even in the latter stages of succession, the size of the soil carbon pool was much smaller than those reported for the low Arctic tundra. Cryptogams contributed the major proportion of phytomass in the later stages. However, because of water limitation, their net primary production was smaller than that of the vascular plants. The compartment model that incorporated major carbon pools and flows suggested that the ecosystem of the later stages is likely to be a net sink of carbon at least for the summer season. Based on the eco-physiological characteristics of the major ecosystem components, we suggest several possible scenarios of future changes in the ecosystem carbon cycle.
BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.
Gráfico 3 -Número de alunos que assinalam corretamente em simultâneo através de cruz e por palavr... more Gráfico 3 -Número de alunos que assinalam corretamente em simultâneo através de cruz e por palavra/conjunto de palavras para designar o mesmo em Outro Qual? As palavras escolhidas para designarem o tipo de texto aparecem descritas no gráfico .
We examined soil microbial activities, i.e., biomass, respiration rate, and temperature dependenc... more We examined soil microbial activities, i.e., biomass, respiration rate, and temperature dependence of the respiration on a glacier foreland in Ny-Å lesund, Svalbard, Norway. We collected soil samples from 4 study sites that were set up along a primary succession (Site 1, the youngest, to Site 4, the oldest). Microbial biomass measured with the SIR method increased with successional age (55 to 724lg C biomass g À1 soil d.w. from Site 1 to Site 4). The microbial respiration rate of the soil was measured in a laboratory with an open-flow infrared gas-analyzer system, changing the temperature from 28 to 208C at 3-48 intervals. The microbial respiration rate increased exponentially with the temperature at all sites. The temperature dependence (Q 10) of the microbial respiration rate ranged from 2.2 to 4.1. The microbial respiration rates at a given temperature increased with succession as a step change (0.48, 0.43, 1.26, and 1.29lg C g À1 soil h À1 at 88C from Site 1 to Site 4, respectively). However, the substrate-specific respiration rate (respiration rate per gram soil carbon) decreased with successional age (0.034 to 0.006lg C mg À1 C soil h À1 from Site 1 to Site 4). A comparison of these respiratory properties with other ecosystems suggested that soil microorganisms in arctic soils have a high potential for decomposition when compared to those of other temperate ecosystems.
Microbial biomass in arctic soil was examined in relation to a primary succession on arctic degla... more Microbial biomass in arctic soil was examined in relation to a primary succession on arctic deglaciated moraines in ~~-~lesund, Svalbard (79¡N 2'E). Soil samples at four study sites representing different successional stages were collected at every 1 cm depth from the soil surface to 3 cm depth in early August 1995. Microbial biomass was measured with a substrate-induced respira- tion procedure. The microbial biomass was highest at the soil surface (0-1 cm depth) in all successional stages, and decreased to a negligible amount at 3 cm depth. Mean microbial biomass in 0-2 cm layer increased from 0.06 mgC glsoil d.w. in the youngest site to 1.03 mgC g4soil d.w. in the oldest site, which is comparable to ecosystems in warmer regions. Throughout all successional stages, there was positive high correlation between soil carbon or nitrogen content and microbial biomass.
The color of photosynthetic apparatus can be used for inferring the process of evolutionary selec... more The color of photosynthetic apparatus can be used for inferring the process of evolutionary selection of photosynthetic pigments and as possible signs of life on distant habitable exoplanets. The absorption spectra of photosynthetic apparatus have close relationships with the spectra and intensity of incident radiation. Most terrestrial plants use specific light-harvesting chlorophylls and carotenoids for photosynthesis and have pale green chloroplasts. However in aquatic ecosystems, there are phototrophs with various colors having different photosynthetic pigments. Oxygenic photosynthesis uses visible light, and far-red photons are not used for this process. While some phototrophic bacteria are able to use far-red photons for their life, they do not generate O2.
ABSTRACT Estimation of the current successional status of long-lived coniferous forests is diffic... more ABSTRACT Estimation of the current successional status of long-lived coniferous forests is difficult especially after several hundred years of human disturbance. However, in Cryptomeria japonica forest on Yakushima Island, the stumps generated by logging activities from the seventeenth to nineteenth centuries remain almost intact without intense rotting. From an inventory of these stumps and long-term monitoring of current stands for more than 25 years, we estimated the forest condition before logging and evaluated the current status of secondary succession. The size structure of Cr. japonica stumps suggested the stumps were composed of two different generations: the stumps of trees present before initiation of logging; and those of trees that regenerated after initiation of logging. In the current forest, the stem number of canopy species is decreasing and that of understory broad-leaved species is increasing. Regenerating Cr. japonica individuals are rare. Before the logging, the forest contained a larger number of larger Cr. japonica trees than the current forest. The results of monitoring the current forest suggested that all coniferous species, including Cr. japonica, were still undergoing self-thinning. The current Cr. japonica forest is in an intermediate stage of secondary succession, but the processes of succession are markedly different between the study plots, depending on their location or previous logging intensity.
Rice (Oryza sativa L.) quality and yield are degraded by high temperature, especially at the ripe... more Rice (Oryza sativa L.) quality and yield are degraded by high temperature, especially at the ripening stage after the heading of panicles. The effect is lethal when the panicle temperature (T p ) is excessively high; therefore, maintaining a low T p is important to avoid deleterious impacts on the grains. Microclimatic factors and plant physiological elements determine the T p . One determining factor is the color (or reflectance) of spikelets that constitute the panicle because it determines the absorption of shortwave radiation energy. An additional factor is the panicle position because it influences heat exchange by the wind and input energy from downward shortwave radiation. In this study, inter-strain differences in spikelet color and panicle height at heading were assessed. The T p of strains differing in panicle color and panicle height were measured with thermocouples. In addition, to estimate the effect of each trait, we adopted a micrometeorological model. Panicle color was quantified using a hyperspectral sensor. Combining the spectral reflectance and spectral radiation, we assessed the effect of panicle color on T p . The differences in panicle color and panicle position significantly affected T p . The strain with a dark panicle had a maximum measured T p about 1.8 °C higher than that of the strain with a light-colored panicle. The T p of a strain with panicles at higher positions was up to 2.0 °C higher than that of a strain with panicles at lower positions. These relationships were consistent with the model estimates. When shortwave radiation was strong, the difference in T p between strains showed a positive correlation, suggesting that the temperature difference was associated with shortwave radiation. Therefore, we concluded that rice strains with a brighter panicle color and low panicle position are less prone to deleterious impacts of high temperature because net radiation is reduced.
Nitrogen is often limiting nutrient for plant growth and is mainly supplied from atmosphere. Fore... more Nitrogen is often limiting nutrient for plant growth and is mainly supplied from atmosphere. Forests can act as a filter for atmospherically deposited nitrogen and maintain background concentration levels of nitrogen in streams. However, recent increases in atmospheric nitrogen deposition have resulted in a shift from net-nitrogen retention to high levels of net-nitrogen loss from forested, resulting in high nitrogen concentration stream water. In the Tatara River Basin, Fukuoka City, nitrogen retention capacity of upland forests has decreased and nitrate concentrations in downstream water have been increasing (Chiwa et al., 2012). This study analyzed NO 3-δN, NO3-δ18O in addition to NO3 concentrations in stream water in the Tatara River Basin to assess the impact of nitrogen saturation forest on downstream water quality. In northern part of the basin, NO 3 concentrations of upstream were lower than downstream. In contrast, in southern part of the basin, NO3 concentrations in upstre...
Plants have evolved and grown under the selection pressure of gravitational force at 1 g on Earth... more Plants have evolved and grown under the selection pressure of gravitational force at 1 g on Earth. In response to this selection pressure, plants have acquired gravitropism to sense gravity and change their growth direction. In addition, plants also adjust their morphogenesis in response to different gravitational forces in a phenomenon known as gravity resistance. However, the gravity resistance phenomenon in plants is poorly understood due to the prevalence of 1 g gravitational force on Earth: not only it is difficult to culture plants at gravity > 1 g(hypergravity) for a long period of time but it is also impossible to create a < 1 genvironment (μg, micro g) on Earth without specialized facilities. Despite these technical challenges, it is important to understand how plants grow in different gravity conditions in order to understand land plant adaptation to the 1 g environment or for outer space exploration. To address this, we have developed a centrifugal device for a prolonged duration of plant culture in hypergravity conditions, and a project to grow plants under the μg environment in the International Space Station is also underway. Our plant material of choice is Physcomitrium (Physcomitrella) patens, one of the pioneer plants on land and a model bryophyte often used in plant biology. In this review, we summarize our latest findings regarding P. patens growth response to hypergravity, with reference to our on-going "Space moss" project. In our ground-based hypergravity experiments, we analyzed the morphological and physiological changes and found unexpected increments of chloroplast size and photosynthesis rate, which might underlie the enhancement of growth and increase in the number of gametophores and rhizoids. We further discussed our approaches at the cellular level and compare the gravity resistance in mosses and that in angiosperms. Finally, we highlight the advantages and perspectives from the space experiments and conclude that research with bryophytes is beneficial to comprehensively and precisely understand gravitational responses in plants.
Клучни зборови: ѕидно сликарство, пигменти, хемиски анализи Апстракт: Во трудот се презентирани р... more Клучни зборови: ѕидно сликарство, пигменти, хемиски анализи Апстракт: Во трудот се презентирани резулатите произлезени од хемиските истражувања на ѕидното сликарство во црквата Св. Никола во Топличкиот манастир, со акцент на анализите насочени кон карактеризација на сликарската палета и применетата сликарска техника. Експерименталните истражувања се засновани на хемиски анализи на голем број примероци земени од различни позиции на живописот во наосот, во припратата и во северниот параклис. Во аналитичкиот дел се презентирани резултатите од извршените анализи за одредување на хемискиот состав на пигментите и врзивниот медиум, со примена на Micro-Raman, FTIR и XRF, како и прикази кои ја одразуваат микро-стратиграфската структура на живописот. Аналитичките сознанија поврзани со сликарската палета и техника придонесоа во потврдувањето на авторството на зографот Јован од Грамоста, укажувајќи дека овој зограф кој се потпишал во припратата, го насликал и наосот со олтарскиот простор, како и северниот параклис. Исто така, аналитичките сознанија помогнаа околу атрибуција на авторството, но и попрецизно одредување на временските рамки во кои настанал првобитниот слој живопис од западниот ѕид на наосот.
The article Why is chlorophyll b only used in light-harvesting systems?, written by Atsushi Kume,... more The article Why is chlorophyll b only used in light-harvesting systems?, written by Atsushi Kume, Tomoko Akitsu, Kenio Nishida Nasahara, was originally published electronically on the publisher's internet portal (currently Springer-Link) on 10 July 2018 without open access.
In 2016, Ecological Research (ER) celebrated its 30th anniversary. ER's goal is to be the leading... more In 2016, Ecological Research (ER) celebrated its 30th anniversary. ER's goal is to be the leading ecological, evolutionary, and biodiversity journal in Asia. This article introduces the development of ER, improvements to its editorial system and their outcomes, and the strategies designed to achieve this goal. ER has already become a leading comprehensive and international publication as shown by statistical evidence and its strong editorial foundation. However, some members of the Ecological Society of Japan (ESJ) retain impressions of an old stereotype about ER. The discrepancy between the current status of the journal and its stereotype may explain why submissions from Japan remain static. A new article category for ER, Biodiversity in Asia, was created to encourage Asian studies. In addition, the Forum category is dedicated to promoting a broad understanding of the ESJ's various activities. To promote open science, the proportion of open access articles in the journal is increasing. The publication of Data papers has been accelerated to improve the public availability of excellent open data sets. ER symposia and seminars provide good opportunities for members to participate. ER financially supports the invitation of scientists internationally to facilitate research exchanges with other countries and consequently promotes the internationalization of the ESJ. The ESJ is open to the world's ecologists, and your participation in developing ER is welcome.
We measured and compared the d 13 C values and nitrogen concentrations within the photosynthetic ... more We measured and compared the d 13 C values and nitrogen concentrations within the photosynthetic parts (Np) of phototrophs growing in different successional stages and different soil conditions at Ny-A ˚lesund, Svalbard, Norway. At all study sites, the Np value of vascular plants ranged from 1.0 to 2.2%. The Np value for most moss species was less than 1.0%; values for lichens were about 0.5%. No significant correlation was detected between Np and d 13 C; however, different plant species occupied distinct fields on a d 13 CeNp plot, with minimal overlap between species. The Np value of Saxifraga oppositifolia, which grew at all of the study sites, ranged from 1.1 to 1.5%. Differences in growth form had no effect on Np. The Np and d 13 C values obtained for S. oppositifolia were confined to within a narrow range regardless of site conditions.
Respiration of the belowground parts of vascular plants: its contribution to total soil respirati... more Respiration of the belowground parts of vascular plants: its contribution to total soil respiration on a successional glacier foreland in Ny-Alesund, Svalbard.
The Arctic terrestrial ecosystem is thought to be extremely susceptible to climate change. Howeve... more The Arctic terrestrial ecosystem is thought to be extremely susceptible to climate change. However, because of the diverse responses of ecosystem components to change, an overall response of the ecosystem carbon cycle to climate change is still hard to predict. In this review, we focus on several recent studies conducted to clarify the pattern of the carbon cycle on the deglaciated area of Ny-Alesund, Svalbard in the high Arctic. Vegetation cover and soil carbon pools tended to increase with the progress of succession. However, even in the latter stages of succession, the size of the soil carbon pool was much smaller than those reported for the low Arctic tundra. Cryptogams contributed the major proportion of phytomass in the later stages. However, because of water limitation, their net primary production was smaller than that of the vascular plants. The compartment model that incorporated major carbon pools and flows suggested that the ecosystem of the later stages is likely to be a net sink of carbon at least for the summer season. Based on the eco-physiological characteristics of the major ecosystem components, we suggest several possible scenarios of future changes in the ecosystem carbon cycle.
BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.
Gráfico 3 -Número de alunos que assinalam corretamente em simultâneo através de cruz e por palavr... more Gráfico 3 -Número de alunos que assinalam corretamente em simultâneo através de cruz e por palavra/conjunto de palavras para designar o mesmo em Outro Qual? As palavras escolhidas para designarem o tipo de texto aparecem descritas no gráfico .
We examined soil microbial activities, i.e., biomass, respiration rate, and temperature dependenc... more We examined soil microbial activities, i.e., biomass, respiration rate, and temperature dependence of the respiration on a glacier foreland in Ny-Å lesund, Svalbard, Norway. We collected soil samples from 4 study sites that were set up along a primary succession (Site 1, the youngest, to Site 4, the oldest). Microbial biomass measured with the SIR method increased with successional age (55 to 724lg C biomass g À1 soil d.w. from Site 1 to Site 4). The microbial respiration rate of the soil was measured in a laboratory with an open-flow infrared gas-analyzer system, changing the temperature from 28 to 208C at 3-48 intervals. The microbial respiration rate increased exponentially with the temperature at all sites. The temperature dependence (Q 10) of the microbial respiration rate ranged from 2.2 to 4.1. The microbial respiration rates at a given temperature increased with succession as a step change (0.48, 0.43, 1.26, and 1.29lg C g À1 soil h À1 at 88C from Site 1 to Site 4, respectively). However, the substrate-specific respiration rate (respiration rate per gram soil carbon) decreased with successional age (0.034 to 0.006lg C mg À1 C soil h À1 from Site 1 to Site 4). A comparison of these respiratory properties with other ecosystems suggested that soil microorganisms in arctic soils have a high potential for decomposition when compared to those of other temperate ecosystems.
Microbial biomass in arctic soil was examined in relation to a primary succession on arctic degla... more Microbial biomass in arctic soil was examined in relation to a primary succession on arctic deglaciated moraines in ~~-~lesund, Svalbard (79¡N 2'E). Soil samples at four study sites representing different successional stages were collected at every 1 cm depth from the soil surface to 3 cm depth in early August 1995. Microbial biomass was measured with a substrate-induced respira- tion procedure. The microbial biomass was highest at the soil surface (0-1 cm depth) in all successional stages, and decreased to a negligible amount at 3 cm depth. Mean microbial biomass in 0-2 cm layer increased from 0.06 mgC glsoil d.w. in the youngest site to 1.03 mgC g4soil d.w. in the oldest site, which is comparable to ecosystems in warmer regions. Throughout all successional stages, there was positive high correlation between soil carbon or nitrogen content and microbial biomass.
The color of photosynthetic apparatus can be used for inferring the process of evolutionary selec... more The color of photosynthetic apparatus can be used for inferring the process of evolutionary selection of photosynthetic pigments and as possible signs of life on distant habitable exoplanets. The absorption spectra of photosynthetic apparatus have close relationships with the spectra and intensity of incident radiation. Most terrestrial plants use specific light-harvesting chlorophylls and carotenoids for photosynthesis and have pale green chloroplasts. However in aquatic ecosystems, there are phototrophs with various colors having different photosynthetic pigments. Oxygenic photosynthesis uses visible light, and far-red photons are not used for this process. While some phototrophic bacteria are able to use far-red photons for their life, they do not generate O2.
ABSTRACT Estimation of the current successional status of long-lived coniferous forests is diffic... more ABSTRACT Estimation of the current successional status of long-lived coniferous forests is difficult especially after several hundred years of human disturbance. However, in Cryptomeria japonica forest on Yakushima Island, the stumps generated by logging activities from the seventeenth to nineteenth centuries remain almost intact without intense rotting. From an inventory of these stumps and long-term monitoring of current stands for more than 25 years, we estimated the forest condition before logging and evaluated the current status of secondary succession. The size structure of Cr. japonica stumps suggested the stumps were composed of two different generations: the stumps of trees present before initiation of logging; and those of trees that regenerated after initiation of logging. In the current forest, the stem number of canopy species is decreasing and that of understory broad-leaved species is increasing. Regenerating Cr. japonica individuals are rare. Before the logging, the forest contained a larger number of larger Cr. japonica trees than the current forest. The results of monitoring the current forest suggested that all coniferous species, including Cr. japonica, were still undergoing self-thinning. The current Cr. japonica forest is in an intermediate stage of secondary succession, but the processes of succession are markedly different between the study plots, depending on their location or previous logging intensity.
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