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21.
22.
Chromosomes responsible for sensitivity of embryo to abscisic acid and dormancy in wheat 总被引:4,自引:0,他引:4
The sensitivity of the embryo to abscisic acid (ABA) has been reported toplay an important role in seed dormancy. Using ditelocentric lines of wheatcv. Chinese Spring (CS, nondormant and ABA insensitive), F2 seedsbetween monosomic lines of CS and a wheat line Kitakei-1354 (dormant,ABA sensitive) and deletion lines of CS chromosome 4A, germinability ofseeds and embryo-half seeds incubated in water and ABA were examined. The results indicated that the long arm of chromosome 4A carried majorgene(s) for the embryo sensitivity to ABA and dormancy. Chromosome2D might be also involved in the sensitivity to ABA. 相似文献
23.
Yasushi Narita Kei Satoh Keiichi Hayashi Tamami Iwase Shigeru Tanaka Yukiko Dokiya Morikazu Hosoe Kazuhiko Hayashi 《Water, air, and soil pollution》2001,130(1-4):1649-1654
In recent years, acid rain has been a social problem all over the world. In Japan, it is also a big problem especially in the metropolitan area. Then, we have measured major ions such as H+, Na+, NH4 +, K+, Mg2+, Ca2+, Cl?, NO3 ?, and SO4 2? in precipitation and dry deposition samples which had been collected at 9 sampling sites at Hiyoshi, Mita, Kashiwa, Shiki, Fujisawa, Yokosuka, Mitaka, Hachiouji, and Ashikaga in Tokyo Metropolitan area for 10 years since 1990. The average pH of precipitation in their sites was 4.56 (n=1906). As the results of multiple regression analysis showed that pH of precipitation was determined by 5 ions such as NH4 +, nssCa2+(non sea salt calcium), nssCl?(non sea salt chloride), NO3 ?, nssSO4 2?(non sea salt sulfate) in the most of the sampling sites. Therefore, it is very important to investigate the behavior of these ions to understand the acidification of rain in Tokyo Metropolitan area. In this study, a long term trend of each ion concentration in precipitation and wet deposition was also investigated the base on the data we had observed at 7 sites for 10 years by the statistical method. 相似文献
24.
Katsuyuki Takahashi Motohiro Hirabayashi Kiyoshi Tanabe Yasuyuki Shibata Masataka Nishikawa Kazuhiko Sakamoto 《Water, air, and soil pollution》2007,185(1-4):305-310
We attempted to elucidate seasonal variations in fossil-fuel-derived carbon (FC) and biomass-derived carbon (BC) in urban atmospheric aerosols. We undertook continuous measurements of the composition of fine particle (PM2.1) in central Tokyo, including the 14C/12C ratio. The percent modern carbon (pMC) contained in all samples averaged 43, and the highest was 54 in late December and the lowest was 31 in early August. From the observed carbonaceous component concentrations and the pMC we could calculate the content ratio of FC and BC in PM2.1 and investigate their seasonal variations. Although there was almost no seasonal variation in the ratio of FC, the ratio of BC was observed to rise in early winter. This indicates that FC is influenced by the emission sources without seasonal variations (such as automobiles driven in urban areas). Furthermore, there is significant correlation between BC and organic carbon (OC), and even for urban areas, it is considered that the contribution of biomass carbon to OC in PM2.1 is high. 相似文献
25.
Kazuhiko Hayashi Yasuhito Igarashi Yukitomo Tsutsumi Yukiko Dokiya 《Water, air, and soil pollution》2001,130(1-4):1667-1672
Aerosol and precipitation samples were obtained at the summit of Mt. Fuji, the highest peak (3776m a.s.l.) in Japan, in the summers of 1997, 1998, and 1999. The mountaintop might be affected by valley wind during the afternoon, but is located in the free troposphere during the morning. The temporal variations of chemical species in the aerosol and precipitation samples correspond with meteorological conditions. The SO4 2? in the aerosol and precipitation exhibits high concentration with low temperature air mass, indicating the influence of long range transport from the Asian Continent. The contribution of the free troposphere to the chemical species obtained at the summit is estimated to be at least 30% during the summer season. 相似文献
26.
Mozammel M. Hoque Kazuyuki Inubushi Shu Miura Kazuhiko Kobayashi Han-Yong Kim Masumi Okada Shingo Yabashi 《Biology and Fertility of Soils》2001,34(6):453-459
An experiment was conducted in an Andosol paddy field in Shizukuishi (Iwate Prefecture, Japan) to determine the effects of free-air CO2 enrichment (FACE) on biological N2-fixation activity and soil microbial biomass C at three levels of N application. Rice (Oryza sativa L. cv. Akitakomachi) plants were grown under ambient CO2 or FACE (ambient +200 µmol mol-1 CO2) conditions throughout the growing season with each treatment having four replicated plots. Three levels of N fertilizer (high, standard and low; 15, 9 and 4 g N m-2, respectively) were applied to examine the effect of different N availability under both CO2 conditions. Soil samples were collected at four different times from upper and lower soil layers (0-1-cm and 1-10-cm soil depths, respectively) and analysed for biological N2-fixation (BNF) activity and microbial biomass C (MBC) by the acetylene reduction and chloroform fumigation-extraction methods, respectively. The amounts of chlorophyll-type compounds (Chls), an index of algal growth, and soil available C were also determined. Compared to the ambient CO2 treatment, the FACE treatment had significantly higher BNF activity in both the upper and lower soil layers at ripening only in low-N soil and at harvest at all three levels of N fertilization rates. MBC was significantly increased by FACE in both the upper and lower soil layers from the middle to later period of the growing season compared to the ambient CO2 treatment. The FACE treatment increased the Chls in the upper soil layers at ripening only in low-N soil and at harvest at all three levels of N fertilization rates. The amount of soil available C was not significantly different between FACE and ambient CO2 treatments in both the upper and lower soil layers throughout the cropping season. From these results it can be concluded that the FACE treatment had a significantly positive influence on BNF activity, MBC and Chls at different levels of N fertilization rates in paddy field during the cropping season. 相似文献
27.
Heavy doses of N fertilizers are commonly applied to green tea fields in Japan, and cause large amount of nitrate leaching
in ground water and emission of ammonia and nitrous oxide (N2O) to the atmosphere. The Denitrification and Decomposition (DNDC) model was tested against experimental data on N2O emissions from the tea field in Nishio, Aichi, Japan. There were reasonable agreements between the simulated and measured
values of N2O emissions for this site. The model was then applied for estimating the environmental impacts as affected by farm management
practices, climate change, and soil properties. The model results were assessed with respect to major indicators of agro-ecosystems
including crop yield, soil organic carbon sequestration, nitrate leaching loss, and N2O emission. The results indicated that use of compost significantly reduced nitrate leaching and N2O emissions in comparison with N fertilizer. When soil pH and texture shifted to non-acidic and coarser soil, N2O emission increased; and a change in temperature and precipitation affected N2O emission, nitrate leaching, and SOC sequestration. This study thus revealed the biogeochemistry model as a powerful tool
in addressing the complex efficacy of the alternative farm management practices in tea fields across various climate and soil
conditions. 相似文献
28.
Furuike S Hossain MD Maki Y Adachi K Suzuki T Kohori A Itoh H Yoshida M Kinosita K 《Science (New York, N.Y.)》2008,319(5865):955-958
F1-adenosine triphosphatase (ATPase) is an ATP-driven rotary molecular motor in which the central gamma subunit rotates inside a cylinder made of three alpha and three beta subunits alternately arranged. The rotor shaft, an antiparallel alpha-helical coiled coil of the amino and carboxyl termini of the gamma subunit, deeply penetrates the central cavity of the stator cylinder. We truncated the shaft step by step until the remaining rotor head would be outside the cavity and simply sat on the concave entrance of the stator orifice. All truncation mutants rotated in the correct direction, implying torque generation, although the average rotary speeds were low and short mutants exhibited moments of irregular motion. Neither a fixed pivot nor a rigid axle was needed for rotation of F1-ATPase. 相似文献
29.
Scherer SW Cheung J MacDonald JR Osborne LR Nakabayashi K Herbrick JA Carson AR Parker-Katiraee L Skaug J Khaja R Zhang J Hudek AK Li M Haddad M Duggan GE Fernandez BA Kanematsu E Gentles S Christopoulos CC Choufani S Kwasnicka D Zheng XH Lai Z Nusskern D Zhang Q Gu Z Lu F Zeesman S Nowaczyk MJ Teshima I Chitayat D Shuman C Weksberg R Zackai EH Grebe TA Cox SR Kirkpatrick SJ Rahman N Friedman JM Heng HH Pelicci PG Lo-Coco F Belloni E Shaffer LG Pober B Morton CC Gusella JF Bruns GA Korf BR 《Science (New York, N.Y.)》2003,300(5620):767-772
30.
Kazuhiko Terazawa Shigehiro Ishizuka Kenji Yamada 《Soil biology & biochemistry》2007,39(10):2689-2692
We measured methane (CH4) emissions from the stem surfaces of mature Fraxinus mandshurica var. japonica trees in a floodplain forest. Flux measurements were conducted almost monthly from May to October 2005, and positive CH4 fluxes were detected throughout the study period, including the leafless season. The mean CH4 flux was 176 and 97 μg CH4 m−2 h−1 at the lower (15 cm above the ground) and upper (70 cm above the ground) stem positions, respectively. The CH4 concentration was lower in soil gas than in ambient air to a depth of at least 40 cm. One possible source of CH4 emitted from the stems might be the dissolved CH4 in groundwater; maximum concentrations were 10,000 times higher than atmospheric CH4 concentrations. Our results suggest that CH4 transport from the submerged soil layer to the atmosphere may occur through internal air spaces in tree bodies. 相似文献