中国笋用竹的栽培优选种

在中国534个竹子种类中，遴选了153种笋用竹。其中刚竹属、箭竹属、牡竹属、寒竹属、香竹属和绿竹属占据笋用竹种类的78％。在笋用竹中，56种具有商业价值，其中的16种具有世界市场。通过对所有笋用竹的商业价值、形态特征、生态特征和种植特点的种植潜力指数评价，将笋用竹分为5个类别：第一类（9种）具有很高的商业价值，大面积种植前景，第二类（33种）可以区域性种植。     

Chemical composition and in vitro ruminal digestibility of Ludwigia grandiflora

Ludwigia grandiflora is an amphibious plant that has been designated as a specific alien plant in Japan. Due to the risk of regeneration on land, plants are burned after eradication. Since L. grandiflora is fertile and rich in biomass, this study investigated the use of L. grandiflora as a feed for ruminants. We measured general components, detergent fiber components, and in vitro dry matter digestibility (IVDMD) using rumen microbes for three forms (terrestrial form, emergent form, and floating-leaved form) of L. grandiflora. In addition, concentrations of hazardous metallic elements were also measured from the viewpoint of feed safety. Crude protein, neutral detergent fiber, acid detergent fiber, and acid detergent lignin were contained 10.31–14.62, 27.83–42.28, 20.54–36.05, and 6.94–18.90 (%DM), respectively. IVDMD was 50.75%–68.24%. Toxic elements such as Pb, Cd, and Hg were not detected in all forms. These results suggest that L. grandiflora could be partially used as alternative roughage for ruminants.     

Metabolism of diethofencarb (isopropyl 3,4-diethoxyphenylcarbamate) in rats: identification of metabolites in urine

Rats were orally given a diethofencarb (isopropyl 3,4-diethoxyphenylcarbamate) labeled with (14)C, at 300 mg/kg/day, for 4 consecutive days, and 11 metabolites in urine were purified by a combination of several chromatographic techniques. The chemical structures of all isolated metabolites were identified by spectroanalyses (NMR and MS). Ten of them were newly identified forms. Five of them were S-conjugates: three mercapturic acid conjugates, one S-methyl conjugate, and one SO-methyl conjugate. The others were two phenoxyacetic acids, hydroxyacetanilide, hydroxyisopropyl carbamate, and oxazolinone derivatives. From the results, the existence of the following reactions in rats can be concluded: (1) deethylation of the 4-ethoxy group; (2) conjugation of phenols with glutathione, gamma-glutamyltranspeptidation and depeptidation of the glutathione to form cysteine conjugates, and N-acetylation of the cysteine; (3) cleavage of the C-S linkage of cysteine conjugates followed by methylation; (4) oxidation of the S-methyl group; (5) cleavage of the carbamate linkage; (6) acetylation of the resultant amino group; (7) oxidation of the acetyl group; (8) oxidation of the isopropyl group; (9) cyclization of the oxidized isopropyl carbamate group; and (10) oxidation of the 4-ethoxy group.     

Polymorphism of insulin‐like growth factor 1 gene is associated with breast muscle yields in chickens

Insulin‐like growth factor‐1 (IGF1) plays an important role in muscle development in chickens. In this study, an F2 chicken population of 362 individuals, obtained from an intercross between high breast muscle yield line males and low breast muscle yield (LB) line females, was constructed for investigating the associations between IGF1 gene and breast muscle yields. The IGF1 sequence was investigated in the grandparents. There were no differences in the exon sequences. However, sequence analysis of the IGF1 promoter revealed a known single nucleotide polymorphism (g.570C > A) in LB line grandparents. PCR – restriction fragment length polymorphism was used for screening the F2 population, which was evaluated for body weight (BW), carcass weight (CW), breast muscle weight (BMW), and breast fillet weight (BFW). Significant associations with the polymorphism were detected for BMW, BFW, BMW% and BFW%, although there were no associations between the polymorphism and BW or CW. The allelic effect on BMW, BFW, BMW% and BFW% acted in additive and dominance modes. We confirmed that the g.570C > A polymorphism is significantly associated with breast muscle yields in the F2 population. Therefore, this polymorphism in the IGF1 gene may help improve breast muscle yields by marker‐assisted selection.     

Effects of porcine leptin receptor gene polymorphisms on backfat thickness,fat area ratios by image analysis,and serum leptin concentrations in a Duroc purebred population

The leptin receptor (LEPR) gene is considered a candidate gene for fatness traits. It is located on SSC 6 in a region in which quantitative trait loci (QTLs) for backfat thickness (BF), fat area ratios, and serum leptin concentration (LEPC) have previously been detected in a Duroc purebred population. The objectives of the present study were to identify porcine LEPR polymorphisms and examine the effects of LEPR polymorphisms on fatness traits in this same population. The Duroc pigs (226 to 953 pigs) were evaluated for BF, fat area ratios using image analysis, and LEPC. A total of seven single nucleotide polymorphisms (SNPs) in the full‐length LEPR coding region were identified in pigs from the base population. Four non‐synonymous SNPs of the LEPR gene and 15 microsatellite markers on SSC 6 were then genotyped in all pigs. During candidate gene analysis, we detected significant effects of the non‐synonymous SNP c.2002C>T in exon 14 on all traits. In fine mapping analysis, significant QTLs for BF, fat area ratios, and LEPC were detected near the LEPR gene in the same region. These results indicated that the c.2002C>T SNP of LEPR has a strong effect on BF, fat area ratios and LEPC.     

Digitaria ciliaris seed banks in untilled and tilled soybean fields

We gained an understanding of the vertical distribution and seasonal dynamics of Digitaria ciliaris (Retz.) Koeler seed banks in untilled and tilled soybean fields using studies on naturally established seed banks and on seeds stored in the field. In untilled fields, D. ciliaris seeds were highly concentrated on or near the soil surface from late autumn to spring, whereas only a few seeds were found on the soil surface in the following summer. One year after tillage, there was a high concentration of the seeds on the soil surface. In the tilled fields, seeds were distributed uniformly throughout the soil profile and were present all year long, with only a few seeds found in the following summer. A study of seeds that were artificially buried or stored on the soil surface verified that D. ciliaris seeds were extremely short-lived in the field and could not form a large, persistent seed bank, even when the seeds were buried by tillage. Tillage contributes to suppression of D. ciliaris seedling emergence by reducing the number of seeds that are on or near the soil surface. Furthermore, D. ciliaris seeds showed a greater need for light in order to germinate throughout the year, even when they were stored on the soil surface. Particularly, light was critical for germination during summer. The light requirement for germination should be one reason why viable D. ciliaris seeds on the soil surface are carried over into the next season in untilled fields.     

Residual thenylchlor concentration in soil water and its phytotoxic activity in soil

The phytotoxic activity of soil-applied thenylchlor (2-chloro- N -[3-methoxy-2-thenyl]-2',6'-dimethylacetanilide) on the growth of rice seedlings and its behavior in two different types of soil, Ryugasaki soil and Tsukuba soil, after application was investigated with emphasis on the concentration in the soil water. The greatest inhibition of thenylchlor on the growth of rice seedlings was found immediately after application to both the Ryugasaki and Tsukuba soils. The phytotoxic activity decreased with time in both soils. However, the rate of decrease in phytotoxic activity was slower in the Ryugasaki soil than in the Tsukuba soil. The concentration of thenylchlor in soil water, the amount adsorbed on the soil solid, and the amount in the total soil reduced with time after application to both soils. The amount of thenylchlor adsorbed on the soil solid phase was more persistent than that in the soil water in both soils and the concentration in the soil water was higher in the Ryugasaki soil than in the Tsukuba soil at any given time. The residual phytotoxic activity of thenylchlor on the growth of the rice seedlings in the soil was highly correlated with its concentration in the soil water but not with the amount in the total soil. These results suggested that the residual phytotoxic activity of thenylchlor in the soil is determined by its concentration in the soil water after application.     

Residual phytotoxic activity of pethoxamid in soil and its concentration in soil water under different soil moisture conditions

The relationship between the residual phytotoxic activity of pethoxamid (2-chloro- N -[2-ethoxyethyl]- N- [2-methyl-1-phenyl-1-propenyl] acetamide) on rice ( Oryza sativa cv. Kiyohatamochi) seedlings and its behavior in soil was investigated under different moisture conditions. The phytotoxic activity of pethoxamid on the shoot growth of rice seedlings in soil was higher in 80% soil moisture content than in 70% and 60% soil moisture contents. The phytotoxic activity in soil in 70% and 80% soil moisture conditions decreased with the increasing time after application, but the phytotoxic activity was slight in 50% soil moisture conditions at any given time after application. The residues of pethoxamid in soil water, the amount adsorbed on soil solid, and the amount in total soil was reduced with the time after application in a similar manner among these soil moisture conditions. The residual phytotoxic activity of pethoxamid on the shoot growth of rice seedlings in soil was more highly correlated with the concentration in soil water than with the amounts adsorbed on soil solid and in total soil. The partition coefficients between the amounts of pethoxamid adsorbed on soil solid and its concentration in soil water were similar among the soils with different moisture conditions at each day, and the partition coefficient increased with the time after application. These results suggested that the residual phytotoxic activity of pethoxamid in soil depends on the decreasing concentration of pethoxamid in soil water with time, except in low soil-moisture conditions, which were insufficient for seedling growth.