Effects of low temperature and shade on relationships between nodulation,vesicular-arbuscular mycorrhizal infection,and shoot growth of soybeans

The effects of low temperature and reduced light on a Glycine-Bradyrhizobium-Glomus spp. symbiosis were examined in pot experiments. Soybean plants, Glycine max L. Merr. cv. Tachiyutaka, were grown with N fertilization or inoculation with Bradyrhizobium japonicum plus P fertilization or inoculation with Glomus mosseae in the glasshouse. After the flowering stage, half the pots with soybean plants were subjected to low temperature (15°C 14h/13°C 10 h) with light reduced by shading. At 0, 7, 16, and 28 days after the application of the treatments, the growth, nodulation, vesicular-arbuscular mycorrhizal (VAM) infection and the N and P contents of the soybean plants were measured. In all symbiont-fertilization combinations, the low-temperature treatment reduced the production of dry matter by the soybeans. Nodulation (weight and number) was slightly reduced by this treatment but the proportion of larger nodules was increased. The root length infected by the VAM fungus was little affected by the low-temperature treatment. Both the nodule weight and the infected root length were linearly related to shoot dry weight regardless of treatment and of the symbiont-fertilization combination used. These results suggest that the growth of the symbionts on the root was in balance with the shoot growth of the host, irrespective of climatic conditions, and imply a considerable degree of host control. P inflows to root systems were greatly affected by low-temperature treatment regardless of the symbiont-fertilization combination. This suggests that a simple comparison of P inflows between mycorrhizal and non-mycorrhizal plants may give misleading information on the effects of low temperature or reduced light conditions on P uptake by mycorrhizal plants.     

Efficient embryogenic callus induction and plant regeneration from embryonic axis explants inQuercus acutissima

Embryogenic callus ofQuercus acutissima was successfully induced from embryogenic cultures, and plants were regenerated from the callus. The development of the techniques involved will allow mass propagation and gene transformation in this species. Embryogenic cultures were formed from embryonic axis explants (i.e., embryos without cotyledons) excised from immature embryos, after culture on Murashige and Skoog (MS) medium containing indolebutyric acid and benzyladenine. Attempts to induce embryogenic cultures from cotyledon explants were unsuccessful. Embryogenic calli were induced at high frequency from embryogenic cultures on MS medium containing 2,4-dichlorophenoxyacetic acid. However, benzyladenine inhibited embryogenic callus formation. Somatic embryo development from embryogenic calli occurred on MS medium in all of the seven cell lines tested. Germination of somatic embryos was induced on half strength MS medium without plant growth regulators. Finally, acclimated plants growing in soil were obtained.     

First capture of post-spawning female of the Japanese eel Anguilla japonica at the southern West Mariana Ridge

Two adult male freshwater eels, Anguilla japonica, were captured in June 2008 in the West Mariana Ridge (13°N, 142°E) in the North Pacific, but collections of females have yet to be reported. In September 2008, we successfully caught two adult female A. japonica, 55.5 and 66.2 cm in total length, in the adjacent but northern area (14°N, 143°E). Six newly hatched eel larvae (pre-leptocephali) were also collected by subsequent plankton sampling conducted near the female catch area. Female adults appeared to be in the post-spawning state, probably a considerable time after spawning, since a small number of remarkably regressed oocytes (50–250 μm in diameter) were observed in the ovaries. Capture of post-spawning female eels and newly hatched larvae near the Suruga Seamount (14°N) together with the previous collection of mature males in the southern area (13°N) corroborates that the area along the West Mariana Ridge is the spawning area of this species, but suggests that the eel spawning may occur over a wider area than previously expected.     

Effects of deep percolation on dissolved inorganic nitrogen exports from forested headwater catchments

We examined the effects of deep percolation on dissolved inorganic nitrogen (DIN) exports from two adjacent weathered granite headwater catchments with different deep percolations of water in the Kiryu Experimental Watershed (KEW), Japan. The DIN output in streamflow was estimated from a regression equation between stream discharge and the DIN load, determined from both monthly sampling data and event-based sampling data. The range of deep percolation of DIN was estimated by multiplying observed DIN concentrations in bedrock groundwater by the deep percolation of water estimated from an annual water budget analysis. We found that the deep percolation of DIN corresponded to 34–76 % and ?18 to 8 % of the total DIN output in catchments where the deep percolation of water was 37–45 % and ?6 to 3 % of annual precipitation, respectively. This means that the deep percolation of DIN is not negligible when estimating the total output of DIN in the former catchment. Moreover, the fact that deep percolating water from upper catchments discharged into a lower catchment in KEW suggests that deep percolation of DIN affects downstream N budgets. Therefore, it is important to account for the deep percolation of DIN when evaluating N budgets in forested headwater catchments as well as downstream catchments.     

Developmental ability of somatic cell nuclear transferred embryos aggregated at the 8-cell stage or 16- to 32-cell stage in cattle

Aggregation of somatic cell nuclear transfer (SCNT) embryos in mice is reported to improve full-term development. In the present study, we attempted to improve the development of SCNT embryos by aggregation in cattle. In Experiment 1, to examine the effect of the timing of aggregation on in vitro development of cumulus-cell NT embryos, we aggregated two or three SCNT embryos (2X or 3X embryos) at the 1-cell, 8-cell and 16- to 32-cell stages. Irrespective of the timing of aggregation, 3X embryos developed to the blastocyst stage at a high rate. However, aggregation did not improve the total blastocyst formation rate of the embryos used. The cell numbers of 3X embryos aggregated at the 1-cell stage and 2X embryos tended to be higher than that of single NT embryos (1X embryos). Furthermore, a significant increase in cell number was observed in 3X embryos aggregated at the 8-cell stage and 16- to 32-cell stage. In Experiment 2, we used fibroblast cells as nuclear donors and examined in vitro development of 3X embryos aggregated at the 8-cell stage and 16- to 32-cell stage. As a result, 3X embryos had high blastocyst formation rates and higher cell numbers than 1X embryos, which was consistent with the results of Experiment 1. In Experiment 3, we examined the full-term developmental ability of 3X embryos aggregated at the 8-cell stage and 16- to 32-cell stage. After transfer of fibroblast-derived NT embryos into recipient animals, a significantly higher pregnancy rate was obtained on Day 60 in 3X embryos than in 1X embryos. Two embryos aggregated at 8-cell stage and one embryo aggregated at the 16- to 32-cell stage developed to term, while no pregnancies derived from 1X embryos that lasted to Day 60. However, two of the cloned calves were stillborn. These results suggest that aggregation of the 8-cell stage or 16- to 32-cell stage SCNT embryos may improve the pregnancy rate, but that it cannot reduce the high incidence of fetal loss and stillbirth, which is often observed in bovine SCNT.     

Molecular cloning, tissue expression, and subcellular localization of porcine peptidoglycan recognition proteins 3 and 4

Peptidoglycan recognition proteins (PGRPs) are innate immune molecules that are present in most invertebrates and vertebrates. Mammals have four PGRPs, PGLYRP1-4. In the present study, we cloned the cDNAs encoding porcine PGLYRP3 and 4 from the esophagus of adult swine. The length of the complete open reading frames of porcine PGLYRP3 and 4 are identical and contain 1125bp encoding 374 amino acid residues. The amino acid sequences of these two proteins were more similar to their human orthologs (78.9% [PGLYRP3] and 73.9% [PGLYRP4]) than to their mouse orthologs (71.3% [PGLYRP3] and 67.9% [PGLYRP4]). Expression analysis revealed that both PGLYRP3 and 4 were more strongly expressed in digestive tract, especially the esophagus, than in immune organs such as spleen or mesenteric lymph nodes in both newborn and adult swine. To analyze the subcellular distribution of porcine PGLYRP1-4, we constructed transfectant cell lines. Western blot and flow cytometric analyses revealed that porcine PGLYRP3 and 4 are not only secreted, but also expressed on the cell surface, unlike PGLYRP1 and 2. These results should help contribute to the understanding of PGLYRP3- and 4-mediated immune responses via their recognition of intestinal microorganisms in newborn and adult swine.     

Chloritization in lowland paddy soils

This paper is concerned with the alteration of clay minerals which takes place when well-aerated lowland soils (Brown lowland soils) are cultivated for growing rice. For this purpose the clay mineral compositions of paddy soils were compared with those of adjacent arable soils at four locations.

In the case of arable soils a larger part of the 14Å spacings collapsed to 10Å on treatment with NH₄NO₃ solution, or on drying at about 100°C, whereas in paddy soils the spacings were more stable to thelie treatments. Cation exchange capacities of clays were always smaller In paddy soils than in arable soils. Alternate treatments of reduction and oxidation somewhat increased the stability of the 14Å spacings to heat treatment.

These results indicate that chloritization is a very common process occurring in lowland paddy sons. Chloritization In paddy soils appears to be closely associated with the seasonal cycle of reduction and oxidation.     

Proton consumption with phosphate adsorption on amorphous fe(iii) hydroxide

Proton consumption with phosphate adsorption on amorphous Fe (III) hydroxide (am-Fe(OH)₃) was compared between two different pH-controlled conditions in a 0.1 mol dm^-3 NaClO₄ solution at initial pH values of 5.50 and 4.50, at 298±0.005 K.

The number of protons caused by phosphate dissociation was subtracted from the total number of protons consumed, then the amount of surface OH groups released by the ligand exchange reaction were determined. When a sequential acid titration by a pH-stat maintained pH values of the systems at initial pH values, the percentage of OH groups released during the ligand exchange reaction was almost constant, 29–37%. When the pH values of the systems increased with phosphate adsorption, the percentage of OH groups released by the ligand exchange reaction varied from -4.3 to 33%. The difference in the proton migration between the two pH-controlled conditions not only depended on the phosphate dissociation, but on the difference in the adsorption mechanism, i.e. the ratio of ligand exchange with OH groups to total phosphate adsorption.     

Tin concentrations in river / bay sediments of Tokyo in 1984 and 2000

Abstract

To analyze in greater detail the fate and behavior of toxic organotin compounds in the environment, total tin (Sn) concentrations were determined for sediments of the Arakawa River, the Sumida River, and Tokyo Bay by using a graphite furnace atomic absorption spectrophotometer (GFAAS). Sn concentrations in 2000 were compared with those of 1984 (8 years before the regulation on tributyltin-based antifouling paint) as well as with other heavy metals (Cu, Ni, Pb, and Zn). The Sn concentrations ranged from 1.04 to 4.43 mg kg^?1 for sediments sampled in 2000. Although the average concentration of Sn in the sediments was low compared with that of 1984, the concentration tended to increase at several sites in 2000. Moreover, the Sn concentration showed significant correlations with the Cu, Ni, Pb, and Zn concentrations. These results suggest that a significant proportion of the overall Sn content in these sediments was probably introduced from the sources other than antifouling paint. The metals extracted from air-dried sediments with 0.1 m HCl showed that the mobility and bioavailability of Sn was low compared with those of other heavy metals.     

Effect of volcanic fumes from Mt. Oyama,Miyakejima Island,on atmospheric deposition,soil solution,and soil properties in Kumagaya,central Japan

Abstract

The chemical nature of Mn in the leaves of Acanthopanax seiadophylloides, Ilex crenata var. paludosa and Kalopanax pictus was investigated.

Successive extraction of freeze-dried and fresh leaf sam pies with various solvents showed that the major portion of Mn (>90%) was extractable with water and 0.2 M HCl.

Electron probe X-ray microanalysis was performed with the fresh leaf tissues of Mn hyper accumulator A. seiadophylloides, before and after shaking with distilled water, 80% methanol and 1 M HCl. Water removed large parts of Mn in the tissue as a whole except in the region of the epidermis. A negligible amount of Mn was removed by 80% methanol; on the other hand, 1 M HCl removed almost all of the Mn in the tissues.

Paper electrophoretic experiments conducted with water and 0.2 M HCl extracts using pyridine-acetic acid buffer (pH 6.5) indicated that Mn in the extracts behaved similarly to Mn²⁺, presumably due to the labile nature of Mn components in the tissues.