The dynamic state of the ionome in roots,nodules, and shoots of soybean under different nitrogen status and at different growth stages

The relative distribution of 22 mineral elements in the roots, nodules and shoots of the soybean (Glycine max L. Merr. cv. Tsurumusume) at R1 (beginning of the flowering stage) and R7 (beginning of the mature stage) was investigated in response to ammonium and manure N treatment. Plants receiving only atmospheric nitrogen served as the negative control. The addition of ammonium sulfate to the soil caused soil acidification, induced Al and Mn toxicities, and significantly reduced the biomass production in roots and nodules. Ca, Mg, Fe, Mn, Cu, and Zn concentrations were significantly higher in shoots, and those of Mo and Co higher in nodules. The addition of manure to the soil significantly enhanced the levels of Sr, Ba, Cr, and Cd in shoots, whereas the concentration of Cs was decreased at R7. Moreover, when the soybean developed from R1 to R7, the levels of essential elements in nodules decreased, whereas those of nonessential elements increased, irrespective of the nitrogen source. Furthermore, the variation in the concentrations of many elements was not consistent for nodules and roots when soybean developed from R1 to R7. The variation of Mn, Zn, B, and Al concentrations was independent of N treatments. However, Ca, Fe, Cu, Mo, and Se levels were affected strongly by N treatments. This study is the first to document the dynamic variation of the soybean ionome in nodules, roots, and shoots from vegetative to reproductive stage of soybean.     

Seasonal and Annual Fluxes of Inorganic Constituents in a Small Catchment of a Japanese Cedar Forest near the Sea of Japan

Fluxes of major ions in rainfall (RF), throughfall plus stemflow (TF + SF), and stream water (SW) were measured for five water years in a small catchment of a Japanese cedar forest near the Sea of Japan. The fluxes of most ions in RF and in TF + SF, including the non-sea-salt constituents, increased from late autumn to midwinter owing to the seasonal westerly wind. The concentrations of most ions in SW showed no obvious seasonal trend during the study period, whereas ${\text{NO}}_3 ^ - $ concentrations were lowest in summer, with a small seasonality. The Ca²⁺ and Mg²⁺ outputs in SW were approximately 3.7 and 1.8 times the TF + SF inputs of these cations, respectively. The large net outputs of base cations in the catchment may indicate a decrease in the soil's acid-neutralizing capacity. Annual dissolved inorganic nitrogen inputs in RF and in TF + SF were 17.7 and 17.9 kg N ha^?1 year^?1, respectively, which exceeded previously published thresholds in Europe and the U.S. (i.e., the values at which these inputs increased ${\text{NO}}_3 ^ - $ levels in SW) and equaled the highest level of nitrogen deposition previously reported in Japan. The ${\text{NO}}_{\text{3}} ^{\text{ - }} $ concentrations in SW were relatively high even in summer. During high-precipitation events, ${\text{NO}}_{\text{3}} ^{\text{ - }} $ concentrations in SW increased with increasing water discharge, and the pH decreased simultaneously during several events. Nitrogen deposition may contribute to the high ${\text{NO}}_{\text{3}} ^{\text{ - }} $ concentrations in SW and the temporary acidification that occurred during the rain events.     

An SNP caused loss of seed shattering during rice domestication

Loss of seed shattering was a key event in the domestication of major cereals. We revealed that the qSH1 gene, a major quantitative trait locus of seed shattering in rice, encodes a BEL1-type homeobox gene and demonstrated that a single-nucleotide polymorphism (SNP) in the 5' regulatory region of the qSH1 gene caused loss of seed shattering owing to the absence of abscission layer formation. Haplotype analysis and association analysis in various rice collections revealed that the SNP was highly associated with shattering among japonica subspecies of rice, implying that it was a target of artificial selection during rice domestication.     

Medium without ammonium accumulation supports the developmental competence of human embryos

L-Glutamine has been shown to play an important role during in vitro culture of mammalian embryos. However, it is easily decomposed into ammonium, which is believed to have deleterious effects on preimplantation embryos. In this study, we assessed prospectively the developmental competence of human embryos cultured in medium containing L-glutamine or a novel stable glutamine derivative and vitamins. The subjects of this study were 41 women who underwent IVF/ET treatment from September to November 2006 and from whom 6 or more oocytes were retrieved. Sibling oocytes were randomly divided into EA/BA (EmbryoAssyst and BlastAssyst containing a novel stable glutamine derivative and vitamins), and BAS groups (BlastAssyst system containing L-glutamine). There was no difference in pronuclear formation rate between EA/BA and BAS (74 vs. 69%). The blastulation rates of embryos based on the number of zygotes cultured in EA/BA on Days 5 (Day 0=insemination, 54%) and 6 (63%) were significantly higher (P<0.05) than those cultured in BAS (Day 5: 33% and Day 6: 45%, respectively). The present data indicate that a medium containing a novel stable glutamine derivative and vitamins supports the developmental competence of human embryos.     

Precision Lattice-Parameter Determination of (Mg,Fe)SiO3 Tetragonal Garnets

The tetragonal garnet (Mg,Fe)SiO(3) is a high-pressure phase of pyroxene that is thought to be a major constituent of the earth's upper mantle. Its crystal structure is similar to that of cubic garnet, but it is slightly distorted to tetragonal symmetry so that its x-ray powder diffraction pattern shows a very small line splitting. A suite of tetragonal garnets with different compositions in the MgSiO(3)-rich portion of the MgSiO(3)-FeSiO(3) system was synthesized at about 20 gigapascals and 2000 degrees C. The lattice parameters a and c of quenched samples were determined by whole-powder-pattern decomposition analysis of Fe Kalpha x-ray powder diffraction data, which has the capacity to resolve to a high degree heavily overlapping reflections. It was found that the lattice parameters can be obtained from the following equations; a (in angstroms) = 11.516 + 0.088x and c (in angstroms) = 11.428 + 0.157x, where x, teh mole fraction of FeSiO(3), is 0.0 相似文献   

Lime-nitrogen application affects nitrification, denitrification, and N2O emission in an acidic tea soil

Lime-N (calcium cyanamide, CaCN₂) acts as both fertilizer and pesticide. Lime-N may reduce nitrous oxide (N₂O) emission from soil, although its effectiveness and the relative mechanisms are not well understood. The aim of the study was to quantify the effect of lime-N on N₂O emission from the acidic soil of tea fields. The study design consisted of two treatments: conventional fertilizer (CF) (application of conventional organo-chemical fertilizer) and lime-N (LN) (application of approximately 53 % of the applied N as lime-N and the remaining as conventional organo-chemical fertilizer). Both treatments had the same amount of N, P₂O₅, and K₂O applied to soil between plant canopies; fertilizer was incorporated into soil. We measured N₂O emissions and environmental and microbial parameters of soil between plant canopies and under the canopy of tea plants, including the concentrations of dicyandiamide and cyanamide derived from lime-N. Nitrous oxide emission from soil between plant canopies was lower in the LN treatment than in the CF treatment, and soil ammonium oxidation activity and soil denitrification rate decreased after lime-N application. We applied the acetylene inhibition technique and analyzed isotopomer ratios of N₂O; the results of both techniques suggested that denitrification was the major process of N₂O production in the soil between plant canopies, despite relatively low water-filled pore space. Cumulative N₂O emission over the 366 days of the experiment was 36.0 % lower in the LN treatment than in the CF treatment (P?<?0.05). Our results suggest that lime-N application decreases N₂O emission by inhibiting both nitrification and denitrification processes in the acidic soil.     

Lime-nitrogen application reduces N2O emission from a vegetable field with imperfectly-drained sandy clay-loam soil

Abstract

We studied the effect of lime-nitrogen (calcium cyanamide, CaCN₂) application on the emission of nitrous oxide (N₂O) from a vegetable field with imperfectly-drained sandy clay-loam soil. Lime-nitrogen acts as both a pesticide and a fertilizer. During the decomposition of lime-nitrogen in the soil, dicyandiamide (DCD), a nitrification inhibitor, is formed, and as a result lime-nitrogen application may mitigate N₂O emission from the soil. The study design consisted of three different nitrogen-application treatments in field plots with a randomized block design. The nitrogen application treatments were: CF (chemical fertilizer), LN (all nitrogen fertilizer applied as lime-nitrogen), and CFD (chemical fertilizer containing DCD). Soil nitrification activity was lower in the LN and CFD plots than in the CF plots, and nitrification was inhibited for a longer period in the LN plots than in the CFD plots. In the LN plots, N₂O emission was lower than those of other treatments from 20 to 40 days after fertilization, a period when large peaks of N₂O emission were observed after rainfall in the CF and CFD plots. Cumulative N₂O emission over 63 days in the CF plots (mean ± standard deviation: 30.2 ± 14.4 mg N₂O m^?2) and CFD plots (24.3 ± 10.8 mg N₂O m^?2) was significantly higher than that in the LN plots (10.7 ± 1.2 mg N₂O m^?2; P < 0.05). Our results suggested that lime-nitrogen application decreased N₂O emission by inhibiting both nitrification and denitrification.     

Habitat utilization,feeding, and growth of wild spotted halibut <Emphasis Type="Italic">Verasper variegatus</Emphasis> in a shallow brackish lagoon: Matsukawa-ura,northeastern Japan

Habitat utilization, feeding, and growth of a rare pleuronectid flatfish, spotted halibut Verasper variegatus, were examined in a brackish lagoon in northeastern Japan: Matsukawa-ura. The distribution and date–length data of spotted halibut collected mainly from beam-trawl samplings during 1983–2008 indicated that age-0 juveniles [n = 25, 6.0–18.0 cm total length (TL)] and older spotted halibut (n = 71, 13.8–43.0 cm TL) inhabited almost the entire northern part of Matsukawa-ura. Comparative distribution surveys of spotted halibut, stone flounder, and marbled flounder during 1985–1989 revealed similar distribution patterns of these flatfishes; the highest densities were found around the central part of Matsukawa-ura, although significantly lower abundance was detected for spotted halibut. Linear growth equations of age-0 juveniles demonstrated that spotted halibut were able to achieve high growth after June, probably because abundant prey (e.g., mysids and gammarids) and suitable physical conditions (warmer water temperature and lower salinity) were present. The main prey items shifted from various crustaceans including mysids, caridean shrimps, and anomurans to brachyura Hemigrapsus spp. (≥20 cm TL). Our study shows that spotted halibut use the shallow brackish lagoon as an important nursery for juveniles, and also as a feeding ground for young and adults.