Response of determinate- and semi-determinate-types of common bean to elevated CO2 concentration in the atmosphere

The growth of determinate-type and semi-determinate -type plants of common beam (Phaseolus vulgaris L.) was studied at elevated (700 μL L^-1) and ambient (350 μL L^p-1) CO, concentrations in an open-top chamber. Successive changes in dry matter production and in the number of stems and branches were investigated. To evaluate the sink-source balance at different CO₂ concentrations, ¹³CO₂ was introduced to the leaves during the pod filling stage and the ¹³C distribution profile was analyzed. In the elevated CO₂ treatment, no significant differences in dry matter production were observed for the determinate -type plants, unlike in the semi-determinate-type ones, where the volume was 1.3 times bigger than those in the ambient CO₂ treatment. This enhanced growth in the semi-determinatetype plants mainly involved the branches. Starch accumulation in leaves at elevated CO₂ concentratton was up to 200 and 300 mg glucose g DML^-1 for determinate- and semi-determinate-types, respectively. Though the increased accumulation of starch under elevated CO₂ treatment was more pronounced in the semi-determinate-type plants, it appeared that photosynthesis was not down-regulated. The net assimilation rate of the semi-determinate-type plants in the elevated CO₂ treatment was generally higher than that in the ambient CO₂ treatment. The semi-determinate-type plants could take advantage of the elevated CO₂ treatment for the distribution of photosynthates to branches, while in the determinate-type plants the growth of the branches could not be expanded, and consequently plant growth was not enhanced by elevated CO₂ treatment.     

Arbuscular mycorrhizal fungal communities associated with some pioneer plants in the lahar area of Mt. Pinatubo,Philippines

An extensive area has been buried due to the repeated occurrence of mud flows (lahars) derived from volcanic deposits during the eruption of Mt. Pinatubo in the Philippines. Most of the area was covered with sparse vegetation consisting of only a few gramineous pioneer plants such as Saccharum spontaneum (site SV). However dense vegetation consisting of wild leguminous plants such as Calpogonium mucunoides showed a patch distribution (site DV). In 1999, we investigated the community composition of AMF at these two sites. S. spontaneum at both sites was slightly colonized with AMF while the leguminous plants were highly colonized. Spores of AMF were collected from the rhizosphere of these plants. Eight spore morphotypes were identified; one each for Acaulospora and Entrophospora colombiana, two for Glomus, one for Paraglomus, and three for Scutellospora. Part of the 18S rRNA gene of AMF colonizing the plant roots was amplified with AMF-specific primers, NS31 and AM1, cloned and sequenced. Fifty-three AMF clones were phylogenetically classified into 8 phylotypes as follows: one each for Acaulospora and E. colombiana, five for Glomus, and one for Scutellospora. Both molecular and morphological examinations showed that the diversity of AMF was comparable to that in other temperate ecosystems with abundant vegetation and did not differ significantly between sites SV and DV, regardless of the vegetation cover. Furthermore, S. spontaneum supported diverse AMF species in spite of its scant growth at site SV. E. colombiana was mostly associated with C. mucunoides. Significance of AMF for the primary plant succession in the lahar area was analyzed.     

Exchangeable Cs/K ratio in soil is an index to estimate accumulation of radioactive and stable Cs in rice plant

Pot and field experiments were conducted to clarify the effect of soil exchangeable potassium (K) and cesium-137 (¹³⁷Cs) on ¹³⁷Cs accumulation and to establish soil index in rice (Oryza sativa L.). Four paddy soils in Fukushima Prefecture, Japan, showing different transfer factors for radioactive Cs derived from the accident of Fukushima Daiichi Nuclear Power Station in the field were compared in terms of ¹³⁷Cs accumulation in rice in a pot experiment. ¹³⁷Cs accumulation in shoots and brown rice widely varied among soils with the transfer factor ranging from 0.018 to 0.068 for shoots and 0.004 to 0.065 for brown rice. ¹³⁷Cs concentration in brown rice and shoots tended to decrease with higher levels of soil exchangeable K, and they were more closely related to the exchangeable Cs/K ratio. Similar relationships between the Cs/K ratio and Cs accumulation in plants were obtained for the stable isotope cesium-133 (¹³³Cs). The distributions of ¹³⁷Cs and ¹³³Cs in grains were also similar and variable among soils. The transfer factors obtained in pot experiments mostly agreed with field observations. The results imply that the exchangeable ¹³⁷Cs/K can be a potential soil index to estimate ¹³⁷Cs accumulation in rice.     

Evaluation of water resources by snow storage using water balance and tank model method in the Tedori River basin of Japan

We evaluate water resources as the difference between the observed and virtual discharges, defined as discharge without snow storage during the snowfall and snowmelt season, in the Tedori River basin of Ishikawa Prefecture, Japan. The virtual discharge was estimated using the Tank model, in which parameters of calculated discharge were determined when the predictions were consistent with the observed discharges except for those during snowfall and snowmelt periods. Precipitation increase factors, i.e., the ratio of precipitation in the basin to that of a Kanazawa site, ranged from 1.46 to 2.00 with an average of 1.68. Water resources by snow storage (WRSS) during 31 years from July 1976 to June 2006 were estimated to be 400–1,500 mm in depth, which could be considered a significant amount. WRSS gradually decreased over time from 1976 to 2006. We propose the water balance method to estimate WRSS and water resources by snowmelt (WRSM), which easily estimates these parameters without the need for any detailed analysis of hydrograph as that of the Tank model. If snowfall decreases due to global warming, we suggest this area would suffer an irrigation water shortage under the water right, especially in the early spring.     

Effect of imidacloprid and fipronil pesticide application on Sympetrum infuscatum (Libellulidae: Odonata) larvae and adults

The effect of imidacloprid and fipronil on Sympetrum infuscatum larvae and adults during the rice cultivation period was monitored using an experimental micro-paddy lysimeter (MPL) system. Twenty-two hatched larvae were laid on the soil surface of each MPL. MPLs were treated with imidacloprid, fipronil, and the control MPL was left untreated. The pesticide concentration, S. infuscatum larval and adult populations, and larval emergence time were monitored in each MPL. The maximum imidacloprid and fipronil concentration in paddy water was 52.8 μg/l at 1 day, and 1.3 μg/l at 6 h, respectively, after the pesticide application. Both pesticides dissipated quickly in paddy water, with half-lives of 8.8 and 5.4 days for imidacloprid and fipronil, respectively. The absence of S. infuscatum larvae and exuviae in the fipronil-treated MPL was remarkable. The larval survival decreased to 63.6 ± 18.2, 15.2 ± 2.6, and 0% in the control, imidacloprid-treated, and fipronil-treated MPLs, respectively, by 9 days after pesticide application. Emergence in the imidacloprid-treated MPL was also significantly lower than that in the control MPL. The observed decrease in the abundances of S. infuscatum larvae and adults in MPLs seems to be both directly and indirectly associated with nursery-box application of fipronil and imidacloprid.     

Effect of synchronization of donor cells in early G1‐phase using shake‐off method on developmental potential of somatic cell nuclear transfer embryos in cattle

In this study, we compared the developmental ability of somatic cell nuclear transfer (SCNT) embryos reconstructed with three bovine somatic cells that had been synchronized in G0‐phase (G0‐SCNT group) or early G1‐phase (eG1‐SCNT group). Furthermore, we investigated the production efficiency of cloned offspring for NT embryos derived from these donor cells. The G0‐phase and eG1‐phase cells were synchronized, respectively, using serum starvation and antimitotic reagent treatment combined with shaking of the plate containing the cells (shake‐off method). The fusion rate in the G0‐SCNT groups (64.2 ± 1.8%) was significantly higher than that of eG1‐SCNT groups (39.2 ± 1.9%) (P < 0.05), but the developmental rates to the blastocyst stage of SCNT embryos per fused oocytes were similar for all groups. The overall production efficiency of the clone offspring in eG1‐SCNT groups (12.7%) per recipient cow was higher than that in G0‐SCNT groups (3%) (P < 0.05). The mean birth weight of cloned calves and the average calving score in the G0‐SCNT groups (48.1 ± 3.4 kg and 3.3 ± 0.3, respectively) was significantly higher (P < 0.05) than those of eG1‐SCNT groups (37.2 ± 2.1 kg and 2.3 ± 0.2, respectively). Results of this study indicate that synchronization of donor cells in eG1‐phase using the shake‐off method improved the overall production efficiency of the clone offspring per transferred embryo.     

Comparison of the effects explained by variations in the bovine PLAG1 and NCAPG genes on daily body weight gain,linear skeletal measurements and carcass traits in Japanese Black steers from a progeny testing program

The c.1326T>G single nucleotide polymorphism (SNP) in the NCAPG gene, which leads to an amino acid change of Ile442 to Met442, was previously identified as a candidate causative variation for a bovine carcass weight quantitative trait loci (QTL) on chromosome 6, which was associated with linear skeletal measurement gains and daily body weight gain at puberty. Recently, we identified the stature quantitative trait nucleotides (QTNs) in the PLAG1‐CHCHD7 intergenic region as the causative variations for another carcass weight QTL on chromosome 14. This study aimed to compare the effects of the two QTL on growth and carcass traits using 768 Japanese Black steers from a progeny testing program and to determine whether a genetic interaction was present between them. The FJX_250879 SNP representing the stature QTL was associated with linear skeletal measurements and average daily body weight gain at early and late periods during adolescence. A genetic interaction between FJX_250879 and NCAPG c.1326T>G was detected only for body and rump lengths. Both were associated with increased carcass weight and Longissimus muscle area, and NCAPG c.1326T>G was also associated with reduced subcutaneous fat thickness and increased carcass yield estimate. These results will provide useful information to improve carcass weight in Japanese Black cattle.     

Blowout conditions and properties of isocyanate resin bonded particleboard manufactured from high-moisture particles using an air-injection press

Blowouts of particleboards were artificially induced by increasing the vapor pressure inside the boards. Isocyanate resin bonded boards were manufactured from high-moisture particles, and the blowouts and board properties were analyzed. Boards with a high resin content of 5 % showed high bonding strength and did not blow out when pressed at 190 °C, but blew out at a raised temperature of 210 °C to increase vapor pressure inside the boards, thereby showing that blowout occurred when vapor pressure inside the boards exceeded the bonding strength of isocyanate resin. Boards with a low resin content of 2.5 % had low bonding strength and blew out when manufactured without air injection, but were successfully manufactured with air injection that prevents blowouts. However, the injection of high-pressure air reduced the strength properties of the board and increased the coefficient of variation, likely due to the discharge of isocyanate resin from the boards. Therefore, very small local blowouts occurred inside the boards, which lowered the strength properties of some specimens and led to a large coefficient of variation. When the pressure of injected air was lowered, the strength properties increased and the coefficient of variation decreased. This was possibly because the low-pressure air allowed isocyanate resin to remain in the boards, resulting in virtually no parts showing very low-strength properties.     

Relationships between sap flow,hydraulic conductivity,and the anatomical characteristics of stems and roots in apple rootstocks of different vigour

Summary

To find a useful parameter that could be related to the degree of rootstock vigour, for rootstock breeding programmes, sap flow, hydraulic conductivity, and the anatomical characteristics of stems and roots were measured in 1-year-old trees of apple rootstocks of different vigour. Sap flow was less active in dwarfing rootstocks than in invigorating rootstocks, when taking leaf area into account, under a controlled temperature of 20ºC with the root zone at 15ºC. The hydraulic conductivities of stems and roots were not consistent with the degree of dwarfing.The hydraulic conductivity of the stem appeared to be related to the diameter and density of the large vessels in the xylem. On the other hand, the phloem-to-xylem ratio in roots with diameters of 1.5 – 2.0 mm, was closely-related to sap flow and the degree of dwarfing. The phloem-to-xylem ratio decreased as the degree of vigour increased. Moreover, the phloem-to-xylem ratio was considered to be related to the ability of roots to absorb and transport water, which was expressed as the root-specific sap flow. Therefore, the phloem-to-xylem ratio could be a useful index for evaluating the potential of apple trees as dwarfing rootstocks.     

Relationships between antithrombogenicity and surface free energy of regenerated silk fibroin films

Silk fibroin (SF) was dissolved in calcium chloride/ethanol/water mixture (1/2/8 in mole ratio) at 70°C for 4 h. The dissolved silk fibroin was regenerated by casting the dialyzed solution into the films. The films were treated with 50% aqueous solution of methanol for different times, and their antithrombogenicity was evaluated byin vitro andin vivo tests.In vivo blood tests were made by a method of peripheral vein indwelling suture. It was found that the silk fibroin had a good anti-thrombogenicity and an absorbability even though the polymer showed foreign body reaction. Finally, the blood compatibilty of silk fibroin films which were subjected to structural change by the methanol treatment, was examined in connection with their interfacial surface energy, and a correlation between these properties was found to be present.