Akm Åsman - Academia.edu (original) (raw)

Papers by Akm Åsman

Tsuchi to biseibutsu, 2003

Darrall, N. M.; The effect of air pollutants on physiological processes in plants. Plant Cell Env... more Darrall, N. M.; The effect of air pollutants on physiological processes in plants. Plant Cell Environ. 12: 1-30 (1989).

Journal of Agricultural Meteorology, 2013

A process-based biogeochemistry model, DNDC-Rice, was modified to simulate rice growth and CH 4 e... more A process-based biogeochemistry model, DNDC-Rice, was modified to simulate rice growth and CH 4 emission under elevated atmospheric CO 2 concentration, [CO 2 ]. It simulates the effect of [CO 2 ] on the photosynthetic rate by an empirical parameter (β-factor), which is calibrated based on observed biomass under varied [CO 2 ]. Rice growth is linked to CH 4 emission through rhizodeposition of C and the rice plant's conductance of CH 4 , which depend on the root biomass and tiller density, respectively. DNDC-Rice was tested using five years of rice growth data and four years of CH 4 emission data from a free-air CO 2 enrichment (FACE) experiment in a Japanese rice field, in which [CO 2 ] was controlled at 200 ppm above ambient. In the experiment, FACE increased the average final aboveground biomass by 11％ and seasonal CH 4 emission by 22％. By calibrating the β-factor of photosynthesis calculation, DNDC-Rice successfully predicted the final aboveground biomass across the years and the [CO 2 ] treatments. However, it underestimated the enhancement of CH 4 emission by FACE, to be only 9％ as the average over the four years. We found this discrepancy to be attributed to the modeling of photosynthesis, root growth and exudation, and rice tiller conductance of CH 4 under elevated [CO 2 ]. These results indicate that DNDC-Rice needs to be further refined using detailed data on these plant processes in order to simulate future CH 4 emission under elevated [CO 2 ].

Journal of Agricultural Meteorology, 2011

In 2010, rice growth and yield were compared between farmer's fields under different fertilizatio... more In 2010, rice growth and yield were compared between farmer's fields under different fertilization practices: application of rice straw and bran for 11 years (O-11), the same but for 2 years (O-2), and a combination of synthetic fertilizer and cow manure (F). With the daily maximum air temperature reaching 34.5 on average across the flowering period, the rice plants showed spikelet sterility at 5.5 , 14.5 , and 21.8 in O-11, O-2, and F fields, respectively. The lower spikelet sterility in O-11 could be attributed to the slower decrease in the SPAD value, which was realized by higher soil fertility in O-11. The slower decline in SPAD value in O-11 could also have helped the rice plants to maintain the fraction of imperfectly filled grain which was comparable or smaller (20.4) than that for F (28.9). The poor performance of the plants in O-2 (25.4) was ascribed to the earlier decline in SPAD value and commencement of lodging. Further studies are warranted into the mechanisms of reduced heat-induced yield loss under organic fertilizer management.

Journal of Agricultural Meteorology, 2009

To evaluate the impact of emission changes in East Asia on the surface ozone concentration, we co... more To evaluate the impact of emission changes in East Asia on the surface ozone concentration, we conducted 1-year calculations with emission inventories for 2000 and 2020, using a one-way nested global-regional chemical transport model (CTM), consisting of global and regional CTMs. The global CTM was based on the chemical atmospheric general circulation model for the study of the atmospheric environment and radiative forcing (CHASER) model, while the regional part is based on the Weather Research and Forecasting (WRF)/Chem model. The anthropogenic emissions in East Asia were taken from the Regional Emission inventory in ASia (REAS). Comparison of the modeled surface ozone with ground-based observations at Mt. Tai showed that the model generally reproduced the diurnal variations of ozone in the North China Plain. For the horizontal distribution of surface ozone concentration, comparison between 2000 and 2020 revealed an ozone decrease of 1-3 ppbv in the North China Plain, where the increase of ozone precursors was most remarkable. An increase of 3-10 ppbv was also apparent in the outflow region of the North China Plain, over the Sichuan Province, Korea, and Japan. Comparison of the diurnal variations of surface ozone over the North China Plain in 2000 and in the "policy failed case" for 2020 (2020PFC) showed ozone levels peaking at 10 more in the latter, due to enhanced ozone production during the daytime.

Annals of botany, 2006

Influences of rising global CO(2) concentration and temperature on plant growth and ecosystem fun... more Influences of rising global CO(2) concentration and temperature on plant growth and ecosystem function have become major concerns, but how photosynthesis changes with CO(2) and temperature in the field is poorly understood. Therefore, studies were made of the effect of elevated CO(2) on temperature dependence of photosynthetic rates in rice (Oryza sativa) grown in a paddy field, in relation to seasons in two years. Photosynthetic rates were determined monthly for rice grown under free-air CO(2) enrichment (FACE) compared to the normal atmosphere (570 vs 370 micromol mol(-1)). Temperature dependence of the maximum rate of RuBP (ribulose-1,5-bisphosphate) carboxylation (V(cmax)) and the maximum rate of electron transport (J(max)) were analysed with the Arrhenius equation. The photosynthesis-temperature response was reconstructed to determine the optimal temperature (T(opt)) that maximizes the photosynthetic rate. There was both an increase in the absolute value of the light-saturated ...

PloS one, 2015

Agriculture is one of the most vulnerable sectors to climate change. Farmers have been exposed to... more Agriculture is one of the most vulnerable sectors to climate change. Farmers have been exposed to multiple stressors including climate change, and they have managed to adapt to those risks. The adaptation actions undertaken by farmers and their decision making are, however, only poorly understood. By studying adaptation practices undertaken by apple farmers in three regions: Nagano and Kazuno in Japan and Elgin in South Africa, we categorize the adaptation actions into two types: farmer initiated bottom-up adaptation and institution led top-down adaptation. We found that the driver which differentiates the type of adaptation likely adopted was strongly related to the farmers' characteristics, particularly their dependence on the institutions, e.g. the farmers' cooperative, in selling their products. The farmers who rely on the farmers' cooperative for their sales are likely to adopt the institution-led adaptation, whereas the farmers who have established their own sales ...

Journal of Agricultural Meteorology, 2008

The chronic effects of ambient levels of O3 on photosynthetic components and radical scavenging s... more The chronic effects of ambient levels of O3 on photosynthetic components and radical scavenging system of leaves at different positions on the main stem of Japanese rice (Oryza sativa L.) were investigated. Two cultivars of Japanese rice (Koshihikari and Kinuhikari) were planted in plastic boxes filled with flooded Andisol in 9 chambers on 15 May, and exposed daily to charcoal-filtered air or O3 at 60 or 100 nl l-1 (ppb)

Free-air CO 2 enrichment, heading and flowering stage of rice, panicle temperature, panicle trans... more Free-air CO 2 enrichment, heading and flowering stage of rice, panicle temperature, panicle transpiration conductance, heat balance on a panicle. Summary OUE H., YOSHIMOTO M. & KOBAYASHI K. 2005. Effects of free-air CO 2 enrichment on leaf and panicle temperatures of rice at heading and flowering stage.-Phyton (Horn, Austria) 45

To evaluate the impact of emission change in East Asia on the surface ozone concentration and cro... more To evaluate the impact of emission change in East Asia on the surface ozone concentration and crop yield loss especially for wheat and rice, we developed a one-way nested global-regional chemical transport model, and conducted 1-year calculations with emission inventories for 2000 and 2020. The model consisted of global and regional CTMs. The global CTM was based on the chemical atmospheric general circulation model for study of atmospheric environment and radiative forcing (CHASER) model, while the regional part is based on the Weather Research and Forecasting (WRF) /Chem model. We have been also implemented a model which estimates stomatal ozone flux into agricultural crops following to EMEP (European Monitoring and Evaluation Programme) Unified Model, to evaluate exceedance of flux-based critical levels for ozone. The anthropogenic emissions in East Asia were taken from the Regional Emission inventory in ASia (REAS). Phenological data for spring wheat, single rice, and double rice in China, Korea, and Japan are taken from statistical data for each country. Comparison of the modeled surface ozone with ground-based observations in China in 2007 and 2008 showed that the model generally reproduced the seasonal and diurnal variations of ozone at the canopy height. For the horizontal distribution of surface ozone concentration, comparison between 2000 and 2020 revealed an ozone increase of 5-20 ppbv in the North China Plain, where the increase of ozone precursors was most remarkable. Remarkable increase of accumulated ozone flux into wheat during its growing season can be seen in the southern part of China. The maximum increase of AFst6 (accumulated stomatal flux of ozone above threshold of 6 nmol m −2 PLA s −1) was 2.4 mmol/m 2 in Kanton Province. Crop yield loss caused by high ozone concentration was also estimated by using AFst6 and AOT40 (accumulated ozone concentration over threshold of 40 ppbv). Both estimates showed that crop yield loss might increase from 7% to 15% in East Asia.

Paddy surface and subsurface soil samples were collected from former Rice-FACE (free-air CO 2 enr... more Paddy surface and subsurface soil samples were collected from former Rice-FACE (free-air CO 2 enrichment) sites with elevated soil/water temperature treatment in successive rice crop season to investigate effect of CO 2 and temperature on microbial biomass, enzyme activities, and methanogenic and methanotrophic activities in a paddy soil. The FACE experiment was conducted in the field, with two CO 2 levels, ambient and ambient + 200 µL/L (FACE), located in Shizukuishi, Iwate, Japan until 2004. A warming treatment of soil/water temperature of 2 degree from transplanting until harvest (May-September 2006) was set up with waterproof heater in flooded water in the field. Soil microbial biomass C were significantly larger in surface layer than those in subsurface soil, but effect of previous CO 2 treatment and warming treatment on microbial biomass were both not significant. Dehydrogenase activity and dissolved organic carbon (DOC) had no significant difference between elevated and ambient temperature, though significantly higher in surface soil than sub-surface soil. Methane (CH 4) production (methanogenic) activity was increased by elevated temperature, but no effect on CH 4 oxidation (methanotrophic) activity. These results indicated that elevated temperature may affect soil microbial processes in different ways.

Journal of Agricultural Meteorology, 1993

Three cucumber cultivars (cv. Suyo, Shimoshirazu jibaikyuuri and Tsukemidori) were grown for 3 we... more Three cucumber cultivars (cv. Suyo, Shimoshirazu jibaikyuuri and Tsukemidori) were grown for 3 weeks in sunlit environmental glass chambers under UV-B (290-320nm) irradiation

Journal of Agricultural Meteorology, 2011

Journal of Agricultural Meteorology, 2008

The stomatal conductance (gs) of rice leaves in vertical canopy layers was measured in both the a... more The stomatal conductance (gs) of rice leaves in vertical canopy layers was measured in both the ambient and FACE fields, where the concentration of ozone ([O3]) was elevated artificially, during the heading and flowering stages, 2007. The gs sub-model of rice was developed by a multiplicative approach with modifications of PAR, VPD, AOT40 and [O3], while the multi-layer model of the O3 uptake process in the rice canopy was developed by incorporating the gs sub-model. By the proposed model, vertical profiles of O3 fluxes on a single leaf (FO3) and in each canopy layer were calculated in the conditions 46.0, 40.2 and 43.6 ppb of [O3] at z 280 cm at 1030, 1200 and 1530 h on August 30. O3 uptake by a single leaf (-FO3) in the upper canopy layer peaked at 1530 h and was smallest at 1200 h. The smallest-FO3 at 1200 h was caused not only by the lowest [O3] but also smaller gs, while the smaller gs at 1200 h was caused by smaller PAR on the flag leaf, even under the largest global solar radiation (SR) condition, because the leaf stands erect. The estimated O3 uptakes in the paddy field were 14.9, 13.7 and 12.1 (nmol m-2 s-1) at 1030, 1200 and 1530 h, respectively. The predicted FO3 under different [O3] conditions by the model revealed that FO3 would exceed the threshold of-6 nmol m-2 s-1 in more than 60 ppb [O3] at 1030 and 1200 h and in more than 50 ppb at 1530 h. The predicted FO3 under different SR conditions with fixed [O3] of 80 ppb revealed that FO3 would reach the threshold in more than 400 W m-2 of SR at 1030 and 1200 h and more than 200 W m-2 at 1530 h under this relatively high [O3] condition.

Soil Science and Plant Nutrition, 2006

An anaerobic incubation experiment was conducted to investigate methane (CH 4) production potenti... more An anaerobic incubation experiment was conducted to investigate methane (CH 4) production potential in soil samples collected from a paddy field after exposure to free-air CO 2 enrichment (FACE). The FACE experiment with two CO 2 levels, ambient and ambient + 200 p.p.m.v CO 2 during the rice growing season, was conducted at Shizukuishi, Iwate Prefecture, Japan. The soil was a wet Andosol. Soil samples were taken from the surface (0-1 cm) and the sub-surface (1-10 cm) soil layers 2 months after rice harvest. Subsamples of the fresh soils were put into glass bottles and submerged under N 2 gas headspace during the incubation. The results showed that, prior to incubation, the contents of total C and dissolved organic C (DOC) were significantly greater in FACE soil than ambient soil. During the incubation, CH 4 production potential was approximately 2-4-fold higher in FACE soil than ambient soil and approximately 500-1,000-fold greater in surface soil than sub-surface soil. In general, the FACE soil contained more DOC than ambient soil, particularly in the surface soil layer. These findings suggest that FACE treatment exerted longterm positive effects on CH 4 production and increased organic C content in this paddy soil, particularly in the surface soil layer.

Plant Production Science, 2005

Rice plants (Oryza sativa L.) were grown under normal (350 µL L-1 CO 2) and CO 2-enriched (660 µ ... more Rice plants (Oryza sativa L.) were grown under normal (350 µL L-1 CO 2) and CO 2-enriched (660 µ L L-1 CO 2) conditions, and 13 CO 2 was supplied to the rice plants after heading to examine the translocation and partitioning of photosynthate at the early grain-fi lling stage. At 2 days after supplying 13 CO 2 , no difference in the 13 C content of the whole plant was observed between the plants grown under normal and CO 2-enriched conditions, but translocation of 13 C from the leaf blade to other plant organs seemed to be accelerated by CO 2 enrichment. Up to 9 days after supplying, 13 CO 2 fi xed into sucrose was mainly used to synthesize starch in the stem rather than translocated to the ear in plants grown under normal conditions. In contrast, the supplied 13 C was rapidly translocated to the ear, and 13 C stored as starch in the stem was also translocated to the ear in plants grown under CO 2-enriched conditions. Therefore, we concluded that CO 2 enrichment accelerated the translocation of carbohydrates to the ear.

Plant and Cell Physiology, 2012

Physiological and biochemical studies on the leaf apoplast have been facilitated by the use of th... more Physiological and biochemical studies on the leaf apoplast have been facilitated by the use of the infiltration-centrifugation technique to collect intercellular washing fluid (IWF). However, this technique has been difficult to implement in rice (Oryza sativa L.) for various reasons. We compared the collection efficiency of leaf IWF between two types of rice varieties (Indica and Japonica), as well as between rice and other species (spinach, snap bean and wheat). Although the extraction of IWF in most species took only 2-3 min, it took up to 35 min in rice. The difficulty in infiltration with rice was ascribed to the small stomatal aperture and hydrophobicity of the leaves. In this study, we have established an improved method for collecting IWF and determining the apoplastic air and water volumes in rice leaves. We have shortened the infiltration time to 8 min via the following improvements: (i) infiltration under outdoor shade in the daytime to prevent stomatal closure and a rise in temperature of the infiltration medium; (ii) soaking of leaves in a surfactant solution to decrease the leaf hydrophobicity; and (iii) continuous pressurization using a sealant injector to facilitate the infiltration. The rapid collection of IWF achieved using this technique will facilitate study of the leaf apoplast in rice.

Plant and Cell Physiology, 2005

An increase in atmospheric CO 2 concentration ([CO 2 ]) is generally expected to enhance photosyn... more An increase in atmospheric CO 2 concentration ([CO 2 ]) is generally expected to enhance photosynthesis and biomass. Rice plants (Oryza sativa L.) were grown in ambient CO 2 (AMB) or free-air CO 2-enrichment (FACE), in which the target [CO 2 ] was 200 µmol mol-1 above AMB. 13 CO 2 was fed to the plants at different stages so we could examine the partitioning of photosynthates. Furthermore, canopy photosynthesis and respiration were measured at those stages. The ratio of 13 C content in the whole plant to the amount of fixed 13 C under FACE was similar to that under AMB at the vegetative stage. However, the ratio under FACE was greater than the ratio under AMB at the grainfilling stage. At the vegetative stage, plants grown under FACE had a larger biomass than those grown under AMB owing to enhancement of canopy photosynthesis by the increased [CO 2 ]. On the other hand, at the grain-filling stage, CO 2 enrichment promoted the partitioning of photosynthate to ears, and plants grown under FACE had a greater weight of ears. However, enhancement of ear weight by CO 2 enrichment was not as great as that of biomass at the vegetative stage. Plants grown under FACE did not necessarily show higher canopy photosynthetic rates at the grain-filling stage. Therefore, we concluded that the ear weight did not increase as much as biomass at the vegetative stage owing to a loss of the advantage in CO 2 gain during the grain-filling period.

New Phytologist, 2001

Rising CO 2-future ecosystems 'Every beginning biology student knows that photosynthesis will inc... more Rising CO 2-future ecosystems 'Every beginning biology student knows that photosynthesis will increase if you give a plant a 'squirt' of CO 2-given enough light, nutrients, and water, and a suitable temperature. Logic tells us that if this is so, then more CO 2 in the atmosphere should mean more photosynthesis. This, in turn, should mean more yield or accumulated carbon in plants. This logic is fine for beginning biology; unfortunately, nature is not that simple' (Lemon, 1983). This Special Issue of New Phytologist focuses on the responses of ecosystems to increased CO 2 concentration. The responses of plants are central to this focus, but the questions being asked have changed, and nature's complexities become paramount. Our concern is the human effect on the composition of the atmosphere and how it could have profound effects on our economic and social systems, options for energy production and use, and our capacity to grow food and fiber for an expanding population. The primary interaction between plants and atmospheric CO 2 is just the starting point for our analysis.

Journal of Experimental Botany, 2013

Rising atmospheric CO 2 concentrations will probably increase rice (Oryza sativa L.) yield but de... more Rising atmospheric CO 2 concentrations will probably increase rice (Oryza sativa L.) yield but decrease grain nitrogen (GN) concentration. Grains attached to different positions in the panicles differ greatly in weight and quality, but their responses to elevated CO 2 (e[CO 2 ]) are poorly understood, which limits our understanding of the mechanisms of yield enhancement and quality degradation. Thus a free-air CO 2 enrichment experiment was conducted to examine the effects of e[CO 2 ] on grain mass (GM), grain carbon (GC), and GN accumulation in the spikelets attached to the upper primary rachis branch (superior spikelets; SS) and those attached to the lower secondary rachis (inferior spikelets; IS). e[CO 2 ] stimulated the rice yield by 13% but decreased the N concentration in the panicle by 7% when averaged over two levels of N fertilizations (P < 0.01). The responses of SS and IS to e[CO 2 ] were different particularly under higher N supply. For SS, e[CO 2 ] decreased GN by 24% (P < 0.01) but did not affect GM. For IS, e[CO 2 ] increased GM by 13% (P < 0.05) but GN was not affected. The reduction of GN due to e[CO 2 ] started to appear at the beginning of grain filling. These results suggest that future [CO 2 ] levels probably stimulate the grain growth of IS, most of which are not marketable due to limited size, at the expense of GN reduction in SS. Translocation of N from SS to IS may be a possible mechanism for reduction in GN of SS. This may degrade the grain quality of marketable rice under e[CO 2 ].

Tsuchi to biseibutsu, 2003

Darrall, N. M.; The effect of air pollutants on physiological processes in plants. Plant Cell Env... more Darrall, N. M.; The effect of air pollutants on physiological processes in plants. Plant Cell Environ. 12: 1-30 (1989).

Journal of Agricultural Meteorology, 2013

A process-based biogeochemistry model, DNDC-Rice, was modified to simulate rice growth and CH 4 e... more A process-based biogeochemistry model, DNDC-Rice, was modified to simulate rice growth and CH 4 emission under elevated atmospheric CO 2 concentration, [CO 2 ]. It simulates the effect of [CO 2 ] on the photosynthetic rate by an empirical parameter (β-factor), which is calibrated based on observed biomass under varied [CO 2 ]. Rice growth is linked to CH 4 emission through rhizodeposition of C and the rice plant's conductance of CH 4 , which depend on the root biomass and tiller density, respectively. DNDC-Rice was tested using five years of rice growth data and four years of CH 4 emission data from a free-air CO 2 enrichment (FACE) experiment in a Japanese rice field, in which [CO 2 ] was controlled at 200 ppm above ambient. In the experiment, FACE increased the average final aboveground biomass by 11％ and seasonal CH 4 emission by 22％. By calibrating the β-factor of photosynthesis calculation, DNDC-Rice successfully predicted the final aboveground biomass across the years and the [CO 2 ] treatments. However, it underestimated the enhancement of CH 4 emission by FACE, to be only 9％ as the average over the four years. We found this discrepancy to be attributed to the modeling of photosynthesis, root growth and exudation, and rice tiller conductance of CH 4 under elevated [CO 2 ]. These results indicate that DNDC-Rice needs to be further refined using detailed data on these plant processes in order to simulate future CH 4 emission under elevated [CO 2 ].

Journal of Agricultural Meteorology, 2011

In 2010, rice growth and yield were compared between farmer's fields under different fertilizatio... more In 2010, rice growth and yield were compared between farmer's fields under different fertilization practices: application of rice straw and bran for 11 years (O-11), the same but for 2 years (O-2), and a combination of synthetic fertilizer and cow manure (F). With the daily maximum air temperature reaching 34.5 on average across the flowering period, the rice plants showed spikelet sterility at 5.5 , 14.5 , and 21.8 in O-11, O-2, and F fields, respectively. The lower spikelet sterility in O-11 could be attributed to the slower decrease in the SPAD value, which was realized by higher soil fertility in O-11. The slower decline in SPAD value in O-11 could also have helped the rice plants to maintain the fraction of imperfectly filled grain which was comparable or smaller (20.4) than that for F (28.9). The poor performance of the plants in O-2 (25.4) was ascribed to the earlier decline in SPAD value and commencement of lodging. Further studies are warranted into the mechanisms of reduced heat-induced yield loss under organic fertilizer management.

Journal of Agricultural Meteorology, 2009

To evaluate the impact of emission changes in East Asia on the surface ozone concentration, we co... more To evaluate the impact of emission changes in East Asia on the surface ozone concentration, we conducted 1-year calculations with emission inventories for 2000 and 2020, using a one-way nested global-regional chemical transport model (CTM), consisting of global and regional CTMs. The global CTM was based on the chemical atmospheric general circulation model for the study of the atmospheric environment and radiative forcing (CHASER) model, while the regional part is based on the Weather Research and Forecasting (WRF)/Chem model. The anthropogenic emissions in East Asia were taken from the Regional Emission inventory in ASia (REAS). Comparison of the modeled surface ozone with ground-based observations at Mt. Tai showed that the model generally reproduced the diurnal variations of ozone in the North China Plain. For the horizontal distribution of surface ozone concentration, comparison between 2000 and 2020 revealed an ozone decrease of 1-3 ppbv in the North China Plain, where the increase of ozone precursors was most remarkable. An increase of 3-10 ppbv was also apparent in the outflow region of the North China Plain, over the Sichuan Province, Korea, and Japan. Comparison of the diurnal variations of surface ozone over the North China Plain in 2000 and in the "policy failed case" for 2020 (2020PFC) showed ozone levels peaking at 10 more in the latter, due to enhanced ozone production during the daytime.

Annals of botany, 2006

Influences of rising global CO(2) concentration and temperature on plant growth and ecosystem fun... more Influences of rising global CO(2) concentration and temperature on plant growth and ecosystem function have become major concerns, but how photosynthesis changes with CO(2) and temperature in the field is poorly understood. Therefore, studies were made of the effect of elevated CO(2) on temperature dependence of photosynthetic rates in rice (Oryza sativa) grown in a paddy field, in relation to seasons in two years. Photosynthetic rates were determined monthly for rice grown under free-air CO(2) enrichment (FACE) compared to the normal atmosphere (570 vs 370 micromol mol(-1)). Temperature dependence of the maximum rate of RuBP (ribulose-1,5-bisphosphate) carboxylation (V(cmax)) and the maximum rate of electron transport (J(max)) were analysed with the Arrhenius equation. The photosynthesis-temperature response was reconstructed to determine the optimal temperature (T(opt)) that maximizes the photosynthetic rate. There was both an increase in the absolute value of the light-saturated ...

PloS one, 2015

Agriculture is one of the most vulnerable sectors to climate change. Farmers have been exposed to... more Agriculture is one of the most vulnerable sectors to climate change. Farmers have been exposed to multiple stressors including climate change, and they have managed to adapt to those risks. The adaptation actions undertaken by farmers and their decision making are, however, only poorly understood. By studying adaptation practices undertaken by apple farmers in three regions: Nagano and Kazuno in Japan and Elgin in South Africa, we categorize the adaptation actions into two types: farmer initiated bottom-up adaptation and institution led top-down adaptation. We found that the driver which differentiates the type of adaptation likely adopted was strongly related to the farmers' characteristics, particularly their dependence on the institutions, e.g. the farmers' cooperative, in selling their products. The farmers who rely on the farmers' cooperative for their sales are likely to adopt the institution-led adaptation, whereas the farmers who have established their own sales ...

Journal of Agricultural Meteorology, 2008

The chronic effects of ambient levels of O3 on photosynthetic components and radical scavenging s... more The chronic effects of ambient levels of O3 on photosynthetic components and radical scavenging system of leaves at different positions on the main stem of Japanese rice (Oryza sativa L.) were investigated. Two cultivars of Japanese rice (Koshihikari and Kinuhikari) were planted in plastic boxes filled with flooded Andisol in 9 chambers on 15 May, and exposed daily to charcoal-filtered air or O3 at 60 or 100 nl l-1 (ppb)

Free-air CO 2 enrichment, heading and flowering stage of rice, panicle temperature, panicle trans... more Free-air CO 2 enrichment, heading and flowering stage of rice, panicle temperature, panicle transpiration conductance, heat balance on a panicle. Summary OUE H., YOSHIMOTO M. & KOBAYASHI K. 2005. Effects of free-air CO 2 enrichment on leaf and panicle temperatures of rice at heading and flowering stage.-Phyton (Horn, Austria) 45

To evaluate the impact of emission change in East Asia on the surface ozone concentration and cro... more To evaluate the impact of emission change in East Asia on the surface ozone concentration and crop yield loss especially for wheat and rice, we developed a one-way nested global-regional chemical transport model, and conducted 1-year calculations with emission inventories for 2000 and 2020. The model consisted of global and regional CTMs. The global CTM was based on the chemical atmospheric general circulation model for study of atmospheric environment and radiative forcing (CHASER) model, while the regional part is based on the Weather Research and Forecasting (WRF) /Chem model. We have been also implemented a model which estimates stomatal ozone flux into agricultural crops following to EMEP (European Monitoring and Evaluation Programme) Unified Model, to evaluate exceedance of flux-based critical levels for ozone. The anthropogenic emissions in East Asia were taken from the Regional Emission inventory in ASia (REAS). Phenological data for spring wheat, single rice, and double rice in China, Korea, and Japan are taken from statistical data for each country. Comparison of the modeled surface ozone with ground-based observations in China in 2007 and 2008 showed that the model generally reproduced the seasonal and diurnal variations of ozone at the canopy height. For the horizontal distribution of surface ozone concentration, comparison between 2000 and 2020 revealed an ozone increase of 5-20 ppbv in the North China Plain, where the increase of ozone precursors was most remarkable. Remarkable increase of accumulated ozone flux into wheat during its growing season can be seen in the southern part of China. The maximum increase of AFst6 (accumulated stomatal flux of ozone above threshold of 6 nmol m −2 PLA s −1) was 2.4 mmol/m 2 in Kanton Province. Crop yield loss caused by high ozone concentration was also estimated by using AFst6 and AOT40 (accumulated ozone concentration over threshold of 40 ppbv). Both estimates showed that crop yield loss might increase from 7% to 15% in East Asia.

Paddy surface and subsurface soil samples were collected from former Rice-FACE (free-air CO 2 enr... more Paddy surface and subsurface soil samples were collected from former Rice-FACE (free-air CO 2 enrichment) sites with elevated soil/water temperature treatment in successive rice crop season to investigate effect of CO 2 and temperature on microbial biomass, enzyme activities, and methanogenic and methanotrophic activities in a paddy soil. The FACE experiment was conducted in the field, with two CO 2 levels, ambient and ambient + 200 µL/L (FACE), located in Shizukuishi, Iwate, Japan until 2004. A warming treatment of soil/water temperature of 2 degree from transplanting until harvest (May-September 2006) was set up with waterproof heater in flooded water in the field. Soil microbial biomass C were significantly larger in surface layer than those in subsurface soil, but effect of previous CO 2 treatment and warming treatment on microbial biomass were both not significant. Dehydrogenase activity and dissolved organic carbon (DOC) had no significant difference between elevated and ambient temperature, though significantly higher in surface soil than sub-surface soil. Methane (CH 4) production (methanogenic) activity was increased by elevated temperature, but no effect on CH 4 oxidation (methanotrophic) activity. These results indicated that elevated temperature may affect soil microbial processes in different ways.

Journal of Agricultural Meteorology, 1993

Three cucumber cultivars (cv. Suyo, Shimoshirazu jibaikyuuri and Tsukemidori) were grown for 3 we... more Three cucumber cultivars (cv. Suyo, Shimoshirazu jibaikyuuri and Tsukemidori) were grown for 3 weeks in sunlit environmental glass chambers under UV-B (290-320nm) irradiation

Journal of Agricultural Meteorology, 2011

Journal of Agricultural Meteorology, 2008

The stomatal conductance (gs) of rice leaves in vertical canopy layers was measured in both the a... more The stomatal conductance (gs) of rice leaves in vertical canopy layers was measured in both the ambient and FACE fields, where the concentration of ozone ([O3]) was elevated artificially, during the heading and flowering stages, 2007. The gs sub-model of rice was developed by a multiplicative approach with modifications of PAR, VPD, AOT40 and [O3], while the multi-layer model of the O3 uptake process in the rice canopy was developed by incorporating the gs sub-model. By the proposed model, vertical profiles of O3 fluxes on a single leaf (FO3) and in each canopy layer were calculated in the conditions 46.0, 40.2 and 43.6 ppb of [O3] at z 280 cm at 1030, 1200 and 1530 h on August 30. O3 uptake by a single leaf (-FO3) in the upper canopy layer peaked at 1530 h and was smallest at 1200 h. The smallest-FO3 at 1200 h was caused not only by the lowest [O3] but also smaller gs, while the smaller gs at 1200 h was caused by smaller PAR on the flag leaf, even under the largest global solar radiation (SR) condition, because the leaf stands erect. The estimated O3 uptakes in the paddy field were 14.9, 13.7 and 12.1 (nmol m-2 s-1) at 1030, 1200 and 1530 h, respectively. The predicted FO3 under different [O3] conditions by the model revealed that FO3 would exceed the threshold of-6 nmol m-2 s-1 in more than 60 ppb [O3] at 1030 and 1200 h and in more than 50 ppb at 1530 h. The predicted FO3 under different SR conditions with fixed [O3] of 80 ppb revealed that FO3 would reach the threshold in more than 400 W m-2 of SR at 1030 and 1200 h and more than 200 W m-2 at 1530 h under this relatively high [O3] condition.

Soil Science and Plant Nutrition, 2006

An anaerobic incubation experiment was conducted to investigate methane (CH 4) production potenti... more An anaerobic incubation experiment was conducted to investigate methane (CH 4) production potential in soil samples collected from a paddy field after exposure to free-air CO 2 enrichment (FACE). The FACE experiment with two CO 2 levels, ambient and ambient + 200 p.p.m.v CO 2 during the rice growing season, was conducted at Shizukuishi, Iwate Prefecture, Japan. The soil was a wet Andosol. Soil samples were taken from the surface (0-1 cm) and the sub-surface (1-10 cm) soil layers 2 months after rice harvest. Subsamples of the fresh soils were put into glass bottles and submerged under N 2 gas headspace during the incubation. The results showed that, prior to incubation, the contents of total C and dissolved organic C (DOC) were significantly greater in FACE soil than ambient soil. During the incubation, CH 4 production potential was approximately 2-4-fold higher in FACE soil than ambient soil and approximately 500-1,000-fold greater in surface soil than sub-surface soil. In general, the FACE soil contained more DOC than ambient soil, particularly in the surface soil layer. These findings suggest that FACE treatment exerted longterm positive effects on CH 4 production and increased organic C content in this paddy soil, particularly in the surface soil layer.

Plant Production Science, 2005

Rice plants (Oryza sativa L.) were grown under normal (350 µL L-1 CO 2) and CO 2-enriched (660 µ ... more Rice plants (Oryza sativa L.) were grown under normal (350 µL L-1 CO 2) and CO 2-enriched (660 µ L L-1 CO 2) conditions, and 13 CO 2 was supplied to the rice plants after heading to examine the translocation and partitioning of photosynthate at the early grain-fi lling stage. At 2 days after supplying 13 CO 2 , no difference in the 13 C content of the whole plant was observed between the plants grown under normal and CO 2-enriched conditions, but translocation of 13 C from the leaf blade to other plant organs seemed to be accelerated by CO 2 enrichment. Up to 9 days after supplying, 13 CO 2 fi xed into sucrose was mainly used to synthesize starch in the stem rather than translocated to the ear in plants grown under normal conditions. In contrast, the supplied 13 C was rapidly translocated to the ear, and 13 C stored as starch in the stem was also translocated to the ear in plants grown under CO 2-enriched conditions. Therefore, we concluded that CO 2 enrichment accelerated the translocation of carbohydrates to the ear.

Plant and Cell Physiology, 2012

Physiological and biochemical studies on the leaf apoplast have been facilitated by the use of th... more Physiological and biochemical studies on the leaf apoplast have been facilitated by the use of the infiltration-centrifugation technique to collect intercellular washing fluid (IWF). However, this technique has been difficult to implement in rice (Oryza sativa L.) for various reasons. We compared the collection efficiency of leaf IWF between two types of rice varieties (Indica and Japonica), as well as between rice and other species (spinach, snap bean and wheat). Although the extraction of IWF in most species took only 2-3 min, it took up to 35 min in rice. The difficulty in infiltration with rice was ascribed to the small stomatal aperture and hydrophobicity of the leaves. In this study, we have established an improved method for collecting IWF and determining the apoplastic air and water volumes in rice leaves. We have shortened the infiltration time to 8 min via the following improvements: (i) infiltration under outdoor shade in the daytime to prevent stomatal closure and a rise in temperature of the infiltration medium; (ii) soaking of leaves in a surfactant solution to decrease the leaf hydrophobicity; and (iii) continuous pressurization using a sealant injector to facilitate the infiltration. The rapid collection of IWF achieved using this technique will facilitate study of the leaf apoplast in rice.

Plant and Cell Physiology, 2005

An increase in atmospheric CO 2 concentration ([CO 2 ]) is generally expected to enhance photosyn... more An increase in atmospheric CO 2 concentration ([CO 2 ]) is generally expected to enhance photosynthesis and biomass. Rice plants (Oryza sativa L.) were grown in ambient CO 2 (AMB) or free-air CO 2-enrichment (FACE), in which the target [CO 2 ] was 200 µmol mol-1 above AMB. 13 CO 2 was fed to the plants at different stages so we could examine the partitioning of photosynthates. Furthermore, canopy photosynthesis and respiration were measured at those stages. The ratio of 13 C content in the whole plant to the amount of fixed 13 C under FACE was similar to that under AMB at the vegetative stage. However, the ratio under FACE was greater than the ratio under AMB at the grainfilling stage. At the vegetative stage, plants grown under FACE had a larger biomass than those grown under AMB owing to enhancement of canopy photosynthesis by the increased [CO 2 ]. On the other hand, at the grain-filling stage, CO 2 enrichment promoted the partitioning of photosynthate to ears, and plants grown under FACE had a greater weight of ears. However, enhancement of ear weight by CO 2 enrichment was not as great as that of biomass at the vegetative stage. Plants grown under FACE did not necessarily show higher canopy photosynthetic rates at the grain-filling stage. Therefore, we concluded that the ear weight did not increase as much as biomass at the vegetative stage owing to a loss of the advantage in CO 2 gain during the grain-filling period.

New Phytologist, 2001

Rising CO 2-future ecosystems 'Every beginning biology student knows that photosynthesis will inc... more Rising CO 2-future ecosystems 'Every beginning biology student knows that photosynthesis will increase if you give a plant a 'squirt' of CO 2-given enough light, nutrients, and water, and a suitable temperature. Logic tells us that if this is so, then more CO 2 in the atmosphere should mean more photosynthesis. This, in turn, should mean more yield or accumulated carbon in plants. This logic is fine for beginning biology; unfortunately, nature is not that simple' (Lemon, 1983). This Special Issue of New Phytologist focuses on the responses of ecosystems to increased CO 2 concentration. The responses of plants are central to this focus, but the questions being asked have changed, and nature's complexities become paramount. Our concern is the human effect on the composition of the atmosphere and how it could have profound effects on our economic and social systems, options for energy production and use, and our capacity to grow food and fiber for an expanding population. The primary interaction between plants and atmospheric CO 2 is just the starting point for our analysis.

Journal of Experimental Botany, 2013

Rising atmospheric CO 2 concentrations will probably increase rice (Oryza sativa L.) yield but de... more Rising atmospheric CO 2 concentrations will probably increase rice (Oryza sativa L.) yield but decrease grain nitrogen (GN) concentration. Grains attached to different positions in the panicles differ greatly in weight and quality, but their responses to elevated CO 2 (e[CO 2 ]) are poorly understood, which limits our understanding of the mechanisms of yield enhancement and quality degradation. Thus a free-air CO 2 enrichment experiment was conducted to examine the effects of e[CO 2 ] on grain mass (GM), grain carbon (GC), and GN accumulation in the spikelets attached to the upper primary rachis branch (superior spikelets; SS) and those attached to the lower secondary rachis (inferior spikelets; IS). e[CO 2 ] stimulated the rice yield by 13% but decreased the N concentration in the panicle by 7% when averaged over two levels of N fertilizations (P < 0.01). The responses of SS and IS to e[CO 2 ] were different particularly under higher N supply. For SS, e[CO 2 ] decreased GN by 24% (P < 0.01) but did not affect GM. For IS, e[CO 2 ] increased GM by 13% (P < 0.05) but GN was not affected. The reduction of GN due to e[CO 2 ] started to appear at the beginning of grain filling. These results suggest that future [CO 2 ] levels probably stimulate the grain growth of IS, most of which are not marketable due to limited size, at the expense of GN reduction in SS. Translocation of N from SS to IS may be a possible mechanism for reduction in GN of SS. This may degrade the grain quality of marketable rice under e[CO 2 ].