All issues
Volume 68, Issue 1
Displaying 1-9 of 9 articles from this issue
- |<
- <
- 1
- >
- >|
Full Papers
-
Etsushi KUMAGAI, Custodio P. TACARINDUA, Koki HOMMA, Tatsuhiko SHIRAIW ...2012 Volume 68 Issue 1 Pages 1-13
Published: March 10, 2012
Released on J-STAGE: March 15, 2012
Advance online publication: September 19, 2011JOURNAL FREE ACCESSThe effects of elevated carbon dioxide concentration ([CO2]) and temperature and their interactions on leaf photosynthesis, reproductive processes, seed weight and seed nitrogen concentration ([N]) of soybeans (Glycine max (L.) Merr.) were investigated using temperature gradient chambers. Plants were grown under four regimes comprising two levels of [CO2], ambient (LC) and ambient +200 μmol mol-1 (HC), and two levels of temperature, low (LT) and high (HT, LT +∼3°C). Plant and seed weights were significantly increased by elevated [CO2] in both temperature regimes. Increased seed weight under elevated [CO2] was mainly because of the production of more nodes and seeds per plant. Increased temperature significantly increased the number of seeds per plant but decreased individual seed weight in both [CO2] regimes. Increased temperature therefore had no effect on seed weight. The increased seed number per plant in the HT regimes resulted from increased pod numbers per node. The light-saturated photosynthetic rate increased with increasing [CO2] and temperature, presumably resulting in more seeds per plant. The reduction in individual seed weight with increased temperature was attributed mainly to lower individual seed growth rate and fewer cotyledon cells per seed. The reduction in individual seed weight with increased temperature was less pronounced in the HC regime than in the LC regime, and there was a significant interaction between [CO2] and temperature. However, there was no interaction between [CO2] and temperature for seed weight. Neither individual effects nor interaction of [CO2] and temperature were observed for seed [N]. This study raises the possibility that projected increases in atmospheric [CO2] during the 21st century will increase the yield of soybeans without decreasing seed [N] in regions that have near or below optimum temperatures (near 25°C or above) for soybean yield.View full abstractDownload PDF (723K) -
Hirofumi NAKAMURA, Takeshi TOKIDA, Mayumi YOSHIMOTO, Hidemitsu SAKAI, ...2012 Volume 68 Issue 1 Pages 15-23
Published: March 10, 2012
Released on J-STAGE: March 15, 2012
JOURNAL FREE ACCESSFree-air CO2 enrichment (FACE) provides a unique platform for testing the response of future ecosystems to higher atmospheric CO2 concentration ([CO2]) without disturbing various ecosystemscale interactions. To investigate adaptations to climate change, it is crucial to test the responses of diverse cultivars and management conditions to higher [CO2]. The older rice-FACE facility at Shizukuishi had an effective area of about 80 m2 for [CO2] treatment in each replicate, which was not large enough to test multiple genotypes and management practices. We report the first-year performance of the Tsukuba rice-FACE system installed at Tsukubamirai, Ibaraki, Japan. The new system was designed to have twice the usable area (>160 m2) of the Shizukuishi system without deteriorating the ability to control [CO2]. We adopted a pure-CO2 injection type system to elevate [CO2] in the FACE ring by 200 μmol mol-1 above ambient (control) plots. Overall temporal [CO2] control of the Tsukuba FACE system was slightly better than of the Shizukuishi system; mean [CO2] in the FACE plots was 584 μmol mol-1, nearly equal to the target [CO2] of 586 μmol mol-1. The one-minute mean [CO2] deviated by <±10% and <±20% from the target [CO2] 73.9% and 91.3% of the time, respectively. Spatial distribution of [CO2] inside the ring strongly depended on wind direction and speed. Relatively uniform [CO2] was achieved near the ring center and in the northwestern direction, yielding an aerial fraction of 66% that experienced a season-mean [CO2] within ±20% of the target. These aspects of spatio-temporal performance are comparable to those of other FACE facilities, indicating that the Tsukuba system can serve as a useful and reliable platform on which to test various rice genotypes that may be beneficial under projected high [CO2] conditions in the future.View full abstractDownload PDF (603K) -
Mai KAMAKURA, Yoshiko KOSUGI, Ryoji NAKAGAWA, Masayuki ITOH2012 Volume 68 Issue 1 Pages 25-33
Published: March 10, 2012
Released on J-STAGE: March 15, 2012
JOURNAL FREE ACCESSWe measured methane (CH4) fluxes of leaves growing in a tropical rainforest and a temperate conifer forest using the closed static chamber method. Leaf samples were chosen from the canopy and forest floor of a tropical rainforest at Pasoh Forest Reserve, Peninsular Malaysia and a temperate forest at Kiryu Experimental Watershed (KEW), central Japan. At Pasoh, we sampled four species from the canopy (Xanthophyllum stipitatum, Dipterocarpus sublamellatus, Ptychopyxis caput-medusae, Neobalanocarpus heimii) and four species from the forest floor (Alphonsea maingayi, Rinorea anguifera, Macaranga lowii, Neobalanocarpus heimii). The leaves of Elaeis guineensis were also sampled at an oil palm plantation near the forest reserve area. At KEW, we sampled the leaves of Chamaecyparis obtusa, from both the top (18 m) and middle (16 m) of the canopy as well as leaves of Eurya japonica at the forest floor. Incubation experiments revealed that CH4 was emitted from leaves of the tested species sampled at two sites, although CH4 fluxes showed variations on a daily basis. These results suggest that tree leaves both at Pasoh and KEW might function as a small CH4 source, but their contribution to the CH4 exchange of the total forest ecosystem is very small compared to the soil CH4 flux.View full abstractDownload PDF (729K) -
Tomohito SANO, Takashi HIRANO, Tomomi TAKEDA, Yasumi FUJINUMA2012 Volume 68 Issue 1 Pages 35-43
Published: March 10, 2012
Released on J-STAGE: March 15, 2012
JOURNAL FREE ACCESSLeaf area index (LAI) is an important parameter used to characterize the canopy structure of forest ecosystems. Disturbances such as thinning change the canopy structure and influence various ecosystem functions. A larch plantation in Hokkaido, Japan was thinned during the winter of 2003-2004, decreasing its basal area density by 23% from 29.7 to 22.8 m2 ha-1. To evaluate the LAI change caused by the thinning, we measured LAI in 2003 and 2004 using a direct method with litter collection (LC) and two indirect methods using a plant canopy analyzer (PCA) and a ground-based laser scanner (LS), although a September 2004 typhoon disaster halted LC measurements. In 2003, the annual maximum LAI measured via the LC (LAILC) was 5.6 m2 m-2, of which the LAILC of broadleaf trees accounted for about half. Using rings 1-5 of five sky sectors, the annual maximum LAI indicated by the PCA (LAIPCA) was 3.4 m2 m-2, demonstrating that the PCA underestimated LAI. However, using rings 1-4 and 1-3, LAIPCA increased to 4.4 and 4.8 m2 m-2, respectively. This result shows that eliminating the outer rings of the PCA improves LAI underestimation because some scattering light reflected by leaves engenders underestimation of LAIPCA when the zenith angle is large. The maximum LAI by the LS (LAILS) was equal to LAILC. However, the LS greatly overestimated LAI in the leaf-fall and leafless seasons. The laser beam is thought to have increased in diameter with distance and consequently underestimated the gap fraction.
Maximum LAIPCA and LAILS after thinning were each half of that before thinning. The rates of decrease were greater than the basal area density, which is linearly related with LAI, because canopy inhomogeneity is expected to cause LAI underestimation after thinning. LAI probably decreased to about 4.6 m2 m-2, assuming that the ratio of LAI to basal area remained constant despite thinning.View full abstractDownload PDF (738K) -
Cattleya CHUTTEANG, Prathomrak NA-NGERN, Ryota MARUSHIMA, Masatoshi AO ...2012 Volume 68 Issue 1 Pages 45-53
Published: March 10, 2012
Released on J-STAGE: March 15, 2012
JOURNAL FREE ACCESSGas-phase hydrogen peroxide (H2O2) is very harmful to plants when combined with ozone (O3). Information on ambient H2O2 concentrations, especially for long durations, is limited not only in Thailand and South East Asia but also in Japan. The objective of the present research was to accumulate data of H2O2 concentrations over long durations in Tokyo and Thailand. Hydrogen peroxide concentrations were monitored at Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan (lat. 35.7°N long. 139.5°E), Kasetsart University, Kamphaeng Saen, Nakhon Pathom (lat. 14.0°N long. 100.0°E) and Mae-On, Chiang Mai (lat. 18.8°N long. 99.2°E), Thailand in 2009, 2010 and 2011. During the measurement period, the monthly average H2O2 concentration in Tokyo ranged from 0.0 to 2.2 ppbv, and showed lower values in May, June and November 2010 and became zero in January, February and April 2011. In Chiang Mai, the monthly average H2O2 concentration was a little higher than that of Tokyo, ranging from 1.2 to 3.1 ppbv. The monthly average H2O2 concentrations in Nakhon Pathom were three to four times higher than those of Tokyo and Chiang Mai in the same period except March and April 2011. The diurnal characteristics of H2O2 concentrations from October to December 2009 in Tokyo and Chiang Mai were similar and high around noon and low in the morning and late afternoon. Nevertheless, the pattern of diurnal characteristics in 2010 at Chiang Mai was high in the morning and gradually decreased in the afternoon and it was different from Tokyo. In the case of Nakhon Pathom, the variation was high each time. Thus, the diurnal characteristics varied from place to place and year to year. A positive correlation between atmospheric H2O2 and O3 and air temperature in Tokyo was found in the present observation.View full abstractDownload PDF (880K) -
Kentaro HAYASHI, Keisuke ONO, Takeshi TOKIDA, Takahiro TAKIMOTO, Masay ...2012 Volume 68 Issue 1 Pages 55-68
Published: March 10, 2012
Released on J-STAGE: March 15, 2012
JOURNAL FREE ACCESSThe aim of the present study was to investigate the air concentrations (mass concentration) and exchange fluxes of inorganic particles, i.e., water-soluble inorganic components in fine and coarse particles, and relevant gases at a paddy field for the single cropping of rice in central Japan. The target chemical species were ammonium (pNH4), nitrate (pNO3), nitrite (pNO2), sulfate (pSO4), and chloride (pCl) for inorganic particles separated into coarse and PM2.5 fractions and ammonia (NH3), nitric acid (HNO3), nitrous acid (HNO2), sulfur dioxide (SO2), and hydrochloric gas (HCl) for the relevant gases. Intensive observations were conducted for approximately one week in the winter of 2009 as a fallow season (winter 2009) and in the summer of 2010 at the heading stage of paddy rice (summer 2010). The filter-pack and gradient methods were used to determine the air concentrations and the exchange fluxes, respectively. The air concentrations of the coarse particles were lower than those of the PM2.5 except pCl and pNO3 in the summer of 2010. The ion balance of PM2.5 implied an acidic condition in the daytime in summer 2010 but neutral conditions at other times. Ammonia showed the highest air concentrations and the largest exchange fluxes in most cases among all target species. The paddy field was usually a sink for the inorganic particles and relevant gases; however, NH3 emission in the summer of 2010, perhaps from the paddy rice, occasionally occurred when the air concentrations of NH3 became very low.View full abstractDownload PDF (902K) -
Fumichika UNO, Toshichika IIZUMI, Motoki NISHIMORI, Yousay HAYASHI2012 Volume 68 Issue 1 Pages 69-76
Published: March 10, 2012
Released on J-STAGE: March 15, 2012
JOURNAL FREE ACCESSA notable declining trend in the eating quality of rice panicles has been observed in Kyushu, Western Japan, since the 1990's. As solar radiation is one of the factors determining eating quality, this study investigated the recent time trends and variations in the mean and accumulated radiation for the ripening period of paddy rice in Kyushu during the period 1979-2007. The 3-year running mean radiation data, which are dynamically downscaled reanalysis data using the non-hydrostatic regional climate model (NHRCM) with a grid interval of 20 km, were used for analysis after the validation. From a meta-analysis of governmental crop statistics, it was found that the ripening period (i.e., the period between heading and harvesting) in Kyushu was shortened by 10 days in a 29-year period and generally occurred between the end of August and early October in the 2000's but between early September and the end of October in the 1980's. The change in the length and timing of the ripening period resulted in decreased accumulated radiation for the period, although the mean radiation during the period increased as a result of the earlier timing of the ripening period. The empirical orthogonal function (EOF) analysis results showed that the earlier timing and shorter ripening period are the most dominant factors explaining the radiation change during the ripening period in Kyushu in the past three decades. In addition, a more westward extension in Pacific anticyclones and an associated change in the locations of precipitation that decreased the mean and accumulated radiation for the ripening period in the area were frequently observed in the 2000's. These results indicate a more adverse radiation condition for paddy rice production in the 2000's compared to the 1980's and 1990's.View full abstractDownload PDF (937K)
Short Papers
-
Koji TAMAI2012 Volume 68 Issue 1 Pages 77-85
Published: March 10, 2012
Released on J-STAGE: March 15, 2012
JOURNAL FREE ACCESSWe examined the spatial variation in soil respiration and the number of required sampling points within 1 m2 plots. Twenty-four collars with 0.0065 m2 surface areas were placed in each plot at two Japanese forest sites: four plots at the Yamashiro forest, a deciduous forest on immature soil and four plots at the Kahoku forest, an evergreen forest on common forest soil. Almost all intra-plot coefficients of variation were 23-32%, with a maximum value of 43%. We concluded that the Yamashiro and Kahoku forest sites would require 40 and 30 sampling collars with 0.0065 m2 surface area when the acceptable error rate was 10%, and 10 and 7 sampling collars when the acceptable error rate was 20%, respectively. These values are similar to those reported by previous studies that focused on larger spatial scales.View full abstractDownload PDF (1166K) -
Satoshi SAKATA, Tatsumi TOMOSHO, Motomu UCHIMURA2012 Volume 68 Issue 1 Pages 87-92
Published: March 10, 2012
Released on J-STAGE: March 15, 2012
JOURNAL FREE ACCESSIn 2010, the highest average temperatures on record were recorded throughout Japan. Consequently, rice suffered extensive high-temperature damage. Determining the relationship between the temperature of irrigation water under such weather conditions and the growth of rice in paddy fields is important for investigating measures to respond to global warming, which is expected to progress in the future. In this study, water temperatures were measured at the intake location of irrigation water from a river, in the agricultural water canals, and in rice paddies; furthermore, a questionnaire survey on the occurrence of high-temperature damage to rice was carried out, after the harvest, among rice farmers in southeastern Miyagi Prefecture. From the water temperature measurements, the water temperature in the surveyed area strongly depended on the water temperature at the intake source, that is, the river water temperature. From the questionnaire results, it was found that as the daily average water temperature rose under conditions of similar air temperatures in the area, the number of occurrences of high-temperature damage in the surrounding area tended to increase. Therefore, to avoid hightemperature damage to rice grain ripening, it is important to obtain water with a low temperature from rivers or reservoirs.View full abstractDownload PDF (810K)
- |<
- <
- 1
- >
- >|