Efficient haploid and doubled haploid production from unfertilized ovule culture of gentians (Gentiana spp.)

Factors affecting reliable plant regeneration from unfertilized ovule culture of gentians (Gentiana spp.) were examined. Cold pretreatment (4°C) of flower buds enhanced or maintained production of embryo-like structure (ELS). When 43 genotypes were surveyed in two different labs, 40 of them produced ELSs ranging from 0.01 to 26.5 ELSs per flower bud. No ELSs could be obtained in three genotypes. A significant correlation (r = 0.64) was observed between the number of ELS per flower and the frequency of responding flower buds. Eight genotypes of G. triflora, which were used as common materials in two different labs, produced ELSs in both labs. The ploidy levels of a total of 1,515 regenerated plantlets were determined, revealing that the majority of these plants consisted of haploids (57.9%) and diploids (34.3%). However, the frequency of haploids and diploids was different between G. triflora and G. scabra, and G. triflora showed higher frequencies of haploids than G. scabra. When haploids were treated with oryzalin for chromosome doubling, diploids and tetraploids were obtained. These results demonstrate that the unfertilized ovule culture technique of gentians is a powerful tool for obtaining haploids and DHs because of its reproducible and reliable nature and application to a wide range of genotypes.     

Effects of salt and low light intensity during the vegetative stage on susceptibility of rice to male sterility induced by chilling stress during the reproductive stage

We tested whether exposing rice plants to abiotic stress (salt or shade) during vegetative growth affects the chilling tolerance of reproductive organs, which is one of the most important traits for rice growing in a cool climate; we used two rice cultivars with different tolerance in two growing seasons. We divided the vegetative growth into three phases to clarify the most sensitive period: 7–22 days after transplanting (DAT), 23–38 DAT and 39–54 DAT. Chilling tolerance of the pre-stressed plants was based on the male sterility induced by low temperatures. Shade and salt stress during all three vegetative growth phases significantly reduced stomatal conductance. Shade decreased the specific leaf weight and the leaf sugar and starch contents, but salt had no significant effect, despite causing leaf damage. Low temperatures during the reproductive stage induced spikelet sterility in all plants, but the magnitude was greater in the salt- and shade-stressed plants of both cultivars, especially those stressed late during vegetative growth. The increased spikelet sterility caused by chilling was closely related to the reduction of the total spikelet number per panicle. This is the first study to show that salt and low light stress during vegetative growth increased the susceptibility of rice plants to chilling damage during panicle development.     

Seasonal Deposition Fluxes of Polycyclic Aromatic Hydrocarbons (PAHs) in Lake Biwa,Japan

Water, Air, & Soil Pollution - The concentrations of Cd, Cu, Fe, Ni, Pb and Zn in the different parts of six bivalves species were determined. From the study conducted, it was found that the...     

Genome‐wide association studies reveal additional related loci for fatty acid composition in a Duroc pig multigenerational population

The aim of the present study was to detect quantitative trait loci affecting fatty acid composition in back fat and intramuscular fat in a Duroc pig population comprising seventh‐generation pedigrees using genome‐wide association studies (GWAS). In total, 305 animals were genotyped using single nucleotide polymorphisms (SNPs) array and five selected SNPs from regions containing known candidate genes related to fatty acid synthesis or metabolism. In total, 24 genome‐wide significant SNP regions were detected in 12 traits, and 76 genome‐wide suggestive SNP regions were detected in 33 traits. The Sus scrofa chromosome (SSC) 7 at 10.3 Mb was significantly associated with C17:0 in intramuscular fat, while the SSC9 at 13.6 Mb was significantly associated with C14:0 in intramuscular fat. The SSC12 at 1.0 Mb was significantly associated with C14:0 in back fat and the SSC14 at 121.0 Mb was significantly associated with C18:0 in intramuscular fat. These regions not only replicated previously reported loci containing some candidate genes involved in fatty acid composition (fatty acid synthase and stearoyl‐CoA desaturase) but also included several additional related loci.     

Determination of adulteration in apple juice by HPLC with novel optical rotation detector

A simple HPLC method for the determination of adulteration in apple juice was developed. The method is based on the detection of D-malate, derived from racemic malic acid, which is added as an acidulant. A variable-wavelength optical rotation detector was used to determine the enantiomeric excess (ee). Using anion-exchange chromatography with a phosphate buffer eluent and UV (210 nm) detection, the limit of detection for L-malate was 2 microg. With an injection of 13.4 microg of malate, the standard deviation of the ee calibration curve was 2.5%. Several apple juice samples were analyzed according to the proposed procedure, and the results agreed with those obtained using enzymatic kits for food analysis.     

试论我国西北干旱区近四十年的区域环境变化问题

我国西北干旱区近四十年来,绿洲环境有所改善,而绿洲外的广大地区环境在恶化。本文论述了造成环境变化的原因及其后果,并提出了保护和改善环境的对策。     

Protective effect of a lignan-containing flaxseed extract against CCl(4)-induced hepatic injury

Carbon tetrachloride (CCl(4)) -induced hepatotoxicity is a commonly used model for investigating lipid peroxidation-related tissue injury. In the present study, the effect of flaxseed extract was observed on histological sections, glutathione-content and DNA strand breaks. Lignan-containing flaxseed extract (1.6 g/kg body weight/day) was daily administered with intragastric injection to rats for three days, on the fourth day, CCl(4) (2 g/kg) was intraperitoneally injected. Liver tissue was sampled at 24 hr after administering CCl(4). Liver-necrosis was observed in CCl(4)-injected rats without pretreatment of flaxseed extract. Pretreatment of flaxseed extract reduced extent of the necrosis found 24 hr after the intraperitoneal administration of CCl(4). Pretreatment of flaxseed extract protect against CCl(4)-induced decrease of reduced glutathione-content measured from reactions with 5,5'-dithiobis-(2-nitrobenzoic acid) and also protect against the elevation of DNA strand breaks in the liver cells measured by comet assay. Flaxseed-extract appears to protect liver cells against CCl(4)-induced necrosis.     

Ozonation of a lignin-carbohydrate complex model compound of the benzyl ether type

Evidence for the presence of lignin-carbohydrate bonds of the benzylic ether type in wood and pulps may be obtained by use of ozonation treatment to selectively degrade the lignin. It was found that the benzyl ether bond in 3-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxy-phenoxy)-3-(methyl--d-glucopyranosid-6-O-yl)-1-propanol was rather stable during ozonation in acetic acid-water-methanol 1631 at 0°C. The corresponding acid, 3,4-dihydroxy-2-(methyl--d-glucopyranosid-6-O-yl)-butanoic acid, was found to be the major reaction product. The use of ozonation followed by acid hydrolysis in connection with studies of lignincarbohydrate linkages is briefly discussed.Part of this paper was presented at the 10th ISWPC, Yokohama, 1999