Nitrogen fixation in paddy soils

Several important features of the N. fixation in paddy fields which were reported previously were confirmed and some new additional results regarding the evaluation of the N₂ fixation in the rhizosphere were obtained by reinvestigation in the fields. In addition, rice plants were cultivated in the submerged soil in pots and various parts of the soil were analyzed for the N₂-fixing activity as well as several other properties. The results of the pot experiments were found to be fairly similar to those observed in the field investigations, indicating the validity of the submerged soil in a pot as a rather simulated model for the actual paddy field. By using this model system, the following facts were ascertained: (1) Water-percolation had almost no effect on the N₂-fixing activities of both the rhizosphere and the non-rhizosphere soils. (2) Suppressing effect of washing the root of rice plant on the N₂-fixing activity was slight in the seedling stage and marked in the tillering and flowering stages. (3) The N₂-fixing activity of a single rice root varied from tip to base.     

Evaluation of useful plants for the treatment of polluted pond water with low N and P concentrations

Eutrophication of ponds for agricultural use has begun to adversely affect rice production and the residential living environment in Japan. Cultivation of useful terrestrial and aquatic plant species in plant-bed filter ditches enables to treat domestic wastewater in addition to resource recycling and amenity functions. We evaluated the ability of several plant species, Italian ryegrass (Lolium multiflorum Lam.), hanana (Brassica campestris L. var.), African marigold (Tages erecta L.), sorghum (Sorghum vulgare Pers.), kenaf (Hibiscus cannabinus L.), papyrus (Cyperus papyrus L.), and reed (Phragmites communis Trin.), to remove nitrogen and phosphorus from polluted pond water whose N and P concentrations were much lower than those in domestic wastewater. Artificial pond water containing 2.5 mg L^-1 of N and 0.5 mg L^-1 of P was supplied to ditches at a loading rate of 1.1 g m^-2 d^-1 for N and 0.21 g m^-2 d^-1 for P. Italian ryegrass, papyrus, or kenaf in ditches removed N and P more effectively than other plants. The average removal rate of Italian ryegrass in ditches was 0.62 g m^-2 d^-1 for N and 0.10 g m^-2 d^-1 for P, that of papyrus 0.81 g m^-2 d^-1 for N and 0.15 g m^-2 d^-1 for P, and that of kenaf 0.73 g m^-2 d^-1 for N and 0.11 g m^-2 d^-1 for P. The influence of N and P concentrations on the removal rates of Italian ryegrass, papyrus, and kenaf was studied. Concentrations at a removal rate of zero were 0.2–0.3 mg L^-1 for N and 0.01–0.03 mg L^-l for P. At low concentrations, the plant removal rates increased sharply with the rise in the concentration. When N concentrations exceeded 0.3–0.6 mg L^-1 and P concentrations 0.10–0.45 mg L^-1, the removal rates were high and less affected by the concentration. It was considered that these plant species could be used most efficiently at the concentrations where removal rates are less restricted.     

Characteristics of free sesquioxides and humic acids in soil distributed under Warm-temperate forest climate in Nyu mountains,Fukui Prefecture,Central Japan

The activity and crystallinity ratios of free iron oxides, and the ΔlogK and RF values of humic acids were analyzed in five soil types in the Nyu mountains, Fukui Prefecture, to examine the relation between the zonality of soils and the bioclimatic conditions under the Warm-temperate deciduous broad-leaved forest climate. The characteristics of free iron oxides and humic acids were as follows: The Dark red soil, Kunimidake series was a Dark Red soil under the Cool-temperate deciduous broad-leaved forest climate; the Dry brown forest soil (reddish), Tega series was a Yellow-Brown Forest soil under the Warm-temperate deciduous broad-leaved forest climate; the Dry brown forest soil, Takasu-1 series and the Yellow soil, Yada series were Yellow-Brown Forest soils under the Warm-temperate lucidophyllous forest climate; and the Red soil, Oshibayama series and the lower parts of the Tega series were paleo-red soils. These results indicated that zonal soils under the Warm-temperate deciduous broad-leaved forest climate were Yellow-Brown Forest soils in the Nyu mountains, Fukui Prefecture. The Dark red soil, Kunimidake series corresponded to a Hyperdystri-Rhodic Cambisol of World Reference Base for Soil Resources, WRB (FAO, ISRIC, and ISSS: World Soil Resources Reports 84, 1998). The Dry brown forest soil (reddish), Tega series, the Dry brown forest soil, Takasu-1 series, and the Red soil, Oshibayama series were compared with the Hyperdystri-Chromic Cambisol (WRB). The Yellow soil, Yada series was a Hypereutri-Chromic Cambisol (WRB).     

Pedogenic characteristics of soils distributed under Warm-temperate forest climate in Nyu mountains,Fukui Prefecture,Central Japan

The bioclimatic conditions, profile morphology and physico-chemical properties of five different soils under the Warm-temperate deciduous broad-leaved forest climate, Warm-temperate lucidophyllous forest climate, and Cool-temperate deciduous broad-leaved forest climate in the northern part of the Nyu mountains in Fukui Pref., Central Japan were examined. The outline of the results is as follows: 1) The Dark red soil, Kunimidake series, derived from pyroxene andesite may have been formed by the hydrothermal action of volcanism. 2) The Dry brown forest soil, Takasu-1 series, showed a brighter colour in the Bw horizon and a sudden decrease in the humus content below the AB horizon, suggesting that this soil was similar to Yellow-Brown Forest soils rather than to Brown Forest soils. 3) The Dry brown forest soil (reddish), Tega series, is likely to be a Yellow-Brown Forest soil derived from the loess which covered the underlying paleo-red soil. 4) The Red soil, Oshibayama series, was a paleo-red soil in which the upper part had been lost by erosion. 5) The Yellow soil, Yada series, on the Takasu coastal terrace was also considered to be a Yellow-Brown Forest soil affected by the seawater components from the neighboring coast. 6) It was suggested that zonal soils formed under the Warm-temperate deciduous broad-leaved forest climate in the northern part of the Nyu mountains, in the northwestern region of Fukui Pref. were Yellow-Brown Forest soils like those under the Warm-temperate lucidophyllous forest climate.     

Comparison of adaptability to flash flood between rice cultivars differing in flash flood tolerance

The mechanism of flash flood tolerance was investigated by using a flash flood-intolerant rice cultivar (Oryza sativa), IR42 and a tolerant one, FR13A. The photosynthetic rate of the rice seedlings from both types of cultivars decreased during submergence, whereas the photosynthetic rate of FR13A remained higher than that of IR42. The decrease in photosynthesis in IR42 was partially due to a higher inhibition of the activities of ribulose-1,5-bisphosphate carboxylase, fructose-1,6-bisphosphatase, and glyceraldehyde-3-phosphate dehydrogenase, than in FR13A. After submergence receded (hereafter referred as “desubmergence”), both types of submerged rice cultivars experienced oxidative damage. However the oxidation of the lipids and proteins in FR13A was maintained at a lower level than that in IR42 after desubmergence. On the other hand, the superoxide dismutase activity in FR13A increased more than that in IR42 after desubmergence. Moreover, the content of total ascorbate (reduced and oxidized ascorbates), a main antioxidant increased in FR13A, while in IR42 the content remained low after desubmergence. It is assumed that the photosynthetic activity during submergence may be related to flash flood tolerance. Moreover, flash flood tolerance requires a rapid stimulation of antioxidant systems after desubmergence.     

Effect of cashew nut shell liquid on metabolic hydrogen flow on bovine rumen fermentation

Effect of cashew nut shell liquid (CNSL), a methane inhibitor, on bovine rumen fermentation was investigated through analysis of the metabolic hydrogen flow estimated from concentrations of short‐chain fatty acids (SCFA) and methane. Three cows were fed a concentrate and hay diet without or with a CNSL‐containing pellet. Two trials were conducted using CNSL pellets blended with only silica (trial 1) or with several other ingredients (trial 2). Methane production was measured in a respiration chamber system, and energy balance and nutrient digestibility were monitored. The estimated flow of metabolic hydrogen demonstrated that a part of metabolic hydrogen was used for hydrogen gas production, and a large amount of it flowed into production of methane and SCFA in both trial 1 and 2, when CNSL was administered to the bovine rumen. The results obtained by regression analyses showed that the effect of CNSL supply on methane reduction was coupled with a significant (P < 0.01) decrease of acetate and a significant (P < 0.01) increase of propionate and hydrogen gas. These findings reveal that CNSL is able to reduce methane and acetate production, and to increase hydrogen gas and propionate production in vivo.     

Relationship Between Fertility at Foal Heat and Blood Biochemistry Parameters Monitored During the Peripartum Period in Thoroughbred Mares

This study aimed to examine fertility at foal heat and its relevance to body condition score (BCS) and blood nutritional metabolites in Thoroughbred mares. Thoroughbred mares foaled from 2006 to 2009 were included and classified into two groups: group C (conception; n = 34), which included mares that conceived during foal heat (within 3 weeks after foaling), and group NC (nonconception; n = 39), which included mares that did not conceive despite mating during their foal heat. BCS and blood samples were obtained 1 month before the expected foaling date and 1, 2, 3, and 4 weeks after foaling. Total protein (TP), albumin (Alb), blood urea nitrogen (BUN), aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), total cholesterol (T-Cho), triglyceride (TG), nonesterified fatty acid (NEFA), calcium (Ca), inorganic phosphate (iP), and magnesium (Mg) levels were measured using an automatic clinical chemistry analyzer. Repeated measures analysis of variance (ANOVA) and Student t-test were used to examine the differences between the two groups. No significant differences were observed between the two groups in any of the above-mentioned parameters at 1 month before the expected foaling date (Student t-test). Furthermore, no significant differences were observed between the two groups in serum levels of TP, Alb, AST, GGT, T-Cho, NEFA, Ca, and Mg and BCS at postpartum periods (repeated measures ANOVA). Serum TG, BUN, and iP levels remained lower in group NC than in group C after foaling (P < .05, repeated measures ANOVA). Although the mechanism by which these nutritional factors affect a decline in reproductive performance remains unclear, our results suggest that blood biochemical tests can detect potential imbalances in nutrition and metabolism, even if there is no difference in BCS.     

Analysis of deflection and dynamic plant characteristics of Cyperus malaccensis Lam

ABSTRACT

In this study, flexural rigidity, natural frequency, and damping coefficient of Cyperus malaccensis Lam. with long stems were measured for application for fluid–structure interaction simulation in a field. Numerical solutions of deflection and natural frequency were calculated by ANSYS with finite element method (FEM). The triangular cross-section shape of C. malaccensis stem has a big neighbourhood of the root and the cross-section has taper structure to become small towards tip direction. Two numerical simulation models for FEM have Model A with a triangular prism shape and Model B with a truncated trigonal pyramidal shape to evaluate the effects of stem tapering. Because of large C. malaccensis stem deflection, an equation for nonlinear deflection was introduced to solve a problem regarding flexural rigidity. Natural frequencies of the stem were estimated using amplitude ratio during stem swinging by forced vibration, captured using a high-speed camera. The Model B corresponded with the measurement, and the results suggested that the stem characteristics were affected by cross-section shape. Damping coefficient was calculated using free vibration response, which was consistent with the analytical solution and numerical data calculated using measured characteristics.     

Thermoplastic flow behavior of steamed wood flour under heat and compression

In this study the thermoplastic flow behavior of steamed wood flour was investigated. First it was demonstrated that steamed Japanese beech flour flowed out of the nozzle under compression at high temperature in a thermal flow test with a capillary rheometer. The effects of the steaming temperature, steaming time, compressive pressure, and moisture content of wood flour on the thermal flow temperature were examined. It was shown that the higher the steaming temperature and compressive pressure, the lower the thermal flow temperature. Also, the thermal flow temperature of the sample steamed at 200°C for 20 min became lowest and increasingly higher over time. Furthermore, the thermal flow temperature became linearly low with increasing moisture content of the sample under 15%, whereas it became essentially constant over 15%. It is clarified that compressive pressure and moisture content as well as the steaming conditions profoundly affect the thermoplastic flow behavior of steamed wood flour.     

Molecular and biological characterization of vascular endothelial growth factor of parapoxviruses isolated from wild Japanese serows (Capricornis crispus)

Contagious dermatitis in domestic and wild ruminants caused by parapoxvirus (PPV) occurs worldwide. Although PPV infections appear in cattle, sheep and goats, the papular, nodular, pustular and ulcerated skin lesions of wild Japanese serows (Capricornis crispus) are significantly more severe than those of other animals. To determine the factors involved in the severity of these skin lesions, we compared the molecular characteristics of 4 PPV isolates from Japanese serows and 2 isolates from sheep in Japan, and also investigated the biological properties of primary endothelial cells from different host species. All of the 6 Japanese isolates harbored a vascular endothelial growth factor (VEGF) gene, which is known as one of the virulence factors of PPVs. Three different amino acid sequences of viral VEGF were identified and the sequence was identical among the 4 isolates from the Japanese serows. The temporal expression pattern of viral VEGF mRNA was almost the same among 3 isolates encoding the 3 different VEGFs in infected cells from different host species. Recombinant forms of the 3 different VEGFs showed the ability to induce vascular permeability and endothelial cell proliferation. Primary endothelial cells from Japanese serows were most responsive to recombinant viral VEGF compared to cells from cattle, sheep, and goats. These results suggest that not only the biological activity of viral VEGF but also the high responsiveness to viral VEGF of endothelial cells might be involved in the severe proliferative skin lesions induced by PPV infection in Japanese serows.