排序方式： 共有57条查询结果，搜索用时 15 毫秒
51.
We propose herein a mathematical model, for calculating the oxygen diffusion coefficient (D) and K m value of a cell (M) based on oxygen concentration-respiration rate curve obtained under the condition that oxygen was supplied by lateral diffusion in roots. The model was deductively developed on the assumption that the roots were uniform and cylindrical and that the oxygen concentration and respiration rate were interdependent. We estimated D and M from the oxygen concentration-respiration curves of rice (cv. Fujisaka 5) and wheat (cv. Chinese Spring) using this model. These values showed a certain range as follows. In rice, 0.003 cm2 h-1 ≤ D < 0.037 cm2 h-1, and 0.55 μmol mL-1 ≤ M < 0.75 μmol mL-1, in wheat, 0.016 cm2 h-1 ≤ D < 0.093 cm2 h-1, and 2.1 μmol mL-1 ≤ M < 2.2 μmol mL-1. By comparing the values, rice appeared to be more adapted to hypoxia than wheat, because rice had lower D and M values implying the existence of a safeguard mechanism and high affinity to oxygen. Higher oxygen uptake rate under hypoxia in rice was derived from the lower M value, which exceeded the low D. 相似文献
52.
Takashi Endo Masayuki Yamaguchi Ryota Kaji Koji Nakagomi Tomomori Kataoka Narifumi Yokogami Toshiki Nakamura Goro Ishikawa Jun-ichi Yonemaru Takeshi Nishio 《Breeding Science》2012,62(4):334-339
It has long been known that a bacterial leaf blight-resistant line in rice obtained from a crossing using ‘Asominori’ as a resistant parent also has resistance to blast, but a blast resistance gene in ‘Asominori’ has not been investigated in detail. In the present study, a blast resistance gene in ‘Asominori’, tentatively named Pias(t), was revealed to be located within 162-kb region between DNA markers YX4-3 and NX4-1 on chromosome 4 and to be linked with an ‘Asominori’ allele of the bacterial leaf blight resistance gene Xa1, tentatively named Xa1-as(t). An ‘Asominori’ allele of Pias(t) was found to be dominant and difference of disease severity between lines having the ‘Asominori’ allele of Pias(t) and those without it was 1.2 in disease index from 0 to 10. Pias(t) was also closely linked with the Ph gene controlling phenol reaction, suggesting the possibility of successful selection of blast resistance using the phenol reaction. Since blast-resistant commercial cultivars have been developed using ‘Asominori’ as a parent, Pias(t) is considered to be a useful gene in rice breeding for blast resistance. 相似文献
53.
54.
Hara Y Yamawaki H Shimada M Okada K Tanai T Ichikawa D Miyake K Kizaki K 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(7):697-702
Concern has been growing about the cardiac toxicity of antimalarial drugs. Artemisinin, a unique type of antimalarial drug originating from a Chinese medicinal plant, has minimal adverse effects, but it has been reported to inhibit delayed rectifier potassium current, a voltage-gated potassium current. However, no studies have been published concerning the effect of artemisinin on ligand-gated potassium currents. Therefore, in the present study, we examined the influence of artemisinin on the acetylcholine receptor-operated potassium current (IK.ACh), a ligand-gated potassium current, in guinea pig atrial myocytes using a patch clamp technique. Artemisinin (1 to 300 microM) inhibited I(K.ACh) induced by extracellular application of both carbachol (1 microM) and adenosine (10 microM) and that induced by intracellular loading of GTPgammaS (100 microM) in a concentration-dependent manner. Artemisinin inhibited carbachol-induced, adenosine-induced, and GTPgammaS-activated IK.ACh within almost the same concentration range. In left atria, artemisinin (1 to 100 microM) partially reversed the shortening of action potential duration induced by carbachol in a concentration-dependent manner. Carbachol-induced negative inotropic action in left atria was also inhibited by artemisinin (10 to 300 microM). In conclusion, we suggest that the anticholinergic action of artemisinin is mediated through inhibition of IK.ACh via inhibition of the muscarinic potassium channel and/or associated GTP-binding proteins. 相似文献
55.
56.
Ippei Iiyama Toshiki Fujimoto Osamu Nagata Shuichi Hasegawa 《Soil Science and Plant Nutrition》2005,51(3):313-322
To evaluate the coexistence of agricultural managements and wetland ecosystem conservation, the Bibai mire, an ombrotrophic mire in Hokkaido, Japan, was selected as an experimental site that had been affected by neighboring agricultural managements. Since the lowering of the level of the groundwater table in the peripheral area of the mire had threatened indigenous vegetations, keeping the groundwater table shallow by trench irrigation seemed to be an effective measure to recover the original vegetation. The objective of the present study was to quantify the amount of water and the effective area of trench irrigation required in a bamboo-invading area in a pristine mire. We constructed a trench 28 m long and irrigated at the rate of 2.22 m3 d−1 in a bamboo-invading area in the mire. And to analyze the hydro-meteorological conditions under the trench irrigation, we measured the saturated hydraulic conductivity of the peat layer (3.8 × 10−3 cm s−1 ), the evapotranspiration rate (2.80 mm d−1 ), the depth of the non-irrigated groundwater table (0.15 m) and the surface gradient (0.00493). In addition, using the mass conservation equation and Darcy's law, we derived a steady state model of the level of the groundwater table formed by trench irrigation, which required the five parameters mentioned above. The irrigated water spread over a distance of only about 15 m to both sides of the trench. The model also estimated that the distance for the irrigated area was 14.6 m and we concluded that the irrigated area was limited within a distance of 20 m distances to both sides of the trench and that the irrigation rate per unit trench length did not exceed 0.12 m2 d−1 for realistic values of the evapotranspiration rate and the saturated hydraulic conductivity in peatland. 相似文献
57.
This note examines the feasibility of an improved slotted bolted connection for timber moment frames. In the improved connection,
steel tubes are inserted into drill holes in glulam and fixed to the glulam with resin injection. Aluminum splice plates with
curved slots, or curved elongated holes, are fastened mechanically by using high-strength bolts that go through the steel
tubes. Since the compression due to bolt tension is fully supported by the steel tubes, the reduction of bolt tension due
to shrinkage of the glulam can be avoided. The use of slotted aluminum splice plates allows stable energy dissipation due
to smooth sliding between the aluminum splice plates and the end surfaces of the steel tubes within the specified range of
rotation angle. Through quasistatic cyclic loading tests of two connection specimens, it was demonstrated that stable and
nearly rigid-plastic hysteresis loops were obtained whose equivalent viscous damping ratio was more than 30% in the range
of rotation angle close to or greater than 1/50 radian. Although further improvement is necessary, the experimental results
demonstrate the feasibility and potential of the present connection. 相似文献