Transmission of resistance to common scab from the diploid to the tetraploid level via 4x-2x crosses in potatoes

Summary Diploid potato clones selected for their reaction to common scab and their ability to produce 2n male gametes were used in a series of crosses to a susceptible tetraploid female parent (cv. Shepody). In addition, two tetraploid clones were also selected for their reaction to common scab and crossed with Shepody as a female parent. Results indicated that resistance to common scab can be effectively transmitted from the diploid to the tetraploid level via 4x-2x crosses. Diploid parents producing 2n pollen via either first division or second division restitution can be used to transmit scab resistance. A relatively small proportion of resistant individuals could be recovered from susceptible x susceptible crosses in both 4x-2x and 4x-4x combinations. The data support a previously developed hypothesis that scab resistance is relatively simply inherited.     

The origin of six-rowed ‘wild’ barley from the western Himalaya

Summary Plants were grown from seed of two-rowed wild barley, Hordeum spontaneum, and six-rowed brittlerachised barley. H. agriocrithon, collected in Ladakh, north-western India. Whereas the H. spontaneum remained true to type, segregation for morphological characters was observed in progeny rows grown from heads of H. agriocrithon plants. The H. agriocrithon heads also showed segregation for a biochemical character, the polypeptide pattern of the endosperm storage protein fraction (hordein). The H. agriocrithon seed therefore originated from natural hybridization between cultivated H. vulgare and weedy H. spontaneum. Crosses of H. vulgare and H. spontaneum gave progeny which resembled H. agriocrithon and showed similar hordein polypeptide segregation patterns. The results indicate that six-rowed brittle-rach ised barleys from the Himalayas have a similar origin to forms found in the Middle East, and that H. agriocrithon does not play a direct role in the evolution of barley.     

Mercury species in potable ground water in southern New Jersey

Water samples from 78 private potable wells in southern New Jersey were collected for mercury analysis in 1991–1992. Analyses were performed for the quantification of reactive, volatile and methyl mercury species. Relationships of mercury with other water quality parameters were evaluated also. Total mercury concentrations varied from <1 ng L^?1 to over 36 Μg L^?1. The dominant forms in which mercury occurred in the wells sampled were Hg? and HgCl₂?, although methyl mercury was present in some wells and comprised up to 8% of the total mercury in the ground water samples.     

Fumonisin B-glucose reaction products are less toxic when fed to swine

The effects of fumonisin B-glucose reaction products in swine diets was examined. Pigs were fed diets containing 528 micromol of total fumonisin B/kg (FB), 528 micromol of total FB-glucose adducts/kg (FB-G, 122 micromol of unreacted FB/kg), or 0 micromol of total FB/kg for 15 days to test the efficacy of the FB-G reaction products in detoxifying FB. Weight gain in FB pigs was lower than in FB-G or controls, which was correlated with feed intake reduction in FB pigs. Serum aspartate aminotransferase, gamma-glutamyltransferase, and total bilirubin in FB pigs were higher than in FB-G or control pigs. Serum sphinganine/shingosine ratios in FB pigs were higher than in FB-G or control pigs. Microscopic examination of tissues from FB pigs showed generalized liver necrosis and apoptosis with marked cellular pleomorphism and disorganized hepatic cords. The liver and kidneys in the FB-G group appeared to be normal. Tissues of controls were free of lesions. Results suggest that dietary FB-G products are less toxic to swine and may provide an detoxification approach in instances of widespread FB grain contamination (p < 0.05).     

Human gut microbial degradation of flavonoids: structure-function relationships

The relationship between chemical structure and gut microbial degradation rates of 14 flavonoids, flavone, apigenin, chrysin, naringenin, kaempferol, genistein, daidzein, daidzin, puerarin, 7,4'-dihydroxyflavone, 6,4'-dihydroxyflavone, 5,4'-dihydroxyflavone, 5,3'-dihydroxyflavone, and 4'-hydroxyflavone, was investigated by anaerobically fermenting the flavonoids with human gut microflora (n = 11 subjects). Degradation rates for the 5,7,4'-trihydroxyl flavonoids, apigenin, genistein, naringenin, and kaempferol, were significantly faster than the other structural motifs. Puerarin was resistant to degradation by the gut microflora. Extensive degradation of flavonoids by gut microflora may result in lower overall bioavailability than those flavonoids that are slowly degraded because rapidly degrading flavonoids are less likely to be absorbed intact.     

地下水埋深对春玉米田土壤水分及产量的影响

通过6种地下水位控制处理和对照春玉米试验,探讨了地下水埋深对春玉米农田土壤水分、产量以及水分利用效率的影响。结果表明,地下水埋深对春玉米0～100cm层次土壤水分的影响较大。地下水位越浅这种影响显得越明显;无论地下水埋深深浅,田间累计地下水补给量变化规律可分为4个阶段,即稳定增长期、缓慢增长期、快速增长期和趋于稳定期。地下水位越高,累计地下水补给量越大,土壤排水量越大。较大降雨后土壤开始排水日期随着地下水埋深加深而滞后;地下水埋深1.0m时春玉米产量和水分利用率最高。地下水位在1.0m以下时,水分利用效率随地下水位加深而减少。     

重齿小蠹聚集信息素诱捕器的应用技术研究

重齿小蠹对人工合成聚集信息素的昼夜反应节律发生在白天7：00～21：00,反应高峰在14：00-19：00,反应模式为＂单峰式—白天型＂;利用人工合成的聚集信息素对重齿小蠹成虫发生期监测表明,成虫扬飞的开始时间为5月20日左右,扬飞高峰期为6月下旬和7月上旬,扬飞末期为8月26日,成虫扬飞的持续期为98 d。2007-2009年大量诱杀防治的试验前、后重齿小蠹致死木平均分别为3.39株/hm2和0.76株/hm2,致死木减少了77.58%,而对照区试验前、后致死木平均分别为15.89株/hm2和18.11株/hm2,致死木增加了13.97%,3 a大量诱杀试验的防治效果显著。     

Human fecal metabolism of soyasaponin I

The metabolism of soyasaponin I (3-O-[alpha-L-rhamnopyranosyl-beta-D-galactopyranosyl-beta-D-glucuronopyranosyl]olean-12-ene-3beta,22beta,24-triol) by human fecal microorganisms was investigated. Fresh feces were collected from 15 healthy women and incubated anaerobically with 10 mmol soyasaponin I/g feces at 37 degrees C for 48 h. The disappearance of soyasaponin I in this in vitro fermentation system displayed apparent first-order rate loss kinetics. Two distinct soyasaponin I degradation phenotypes were observed among the subjects: rapid soyasaponin degraders with a rate constant k = 0.24 +/- 0.04 h(-)(1) and slow degraders with a k = 0.07 +/- 0.02 h(-)(1). There were no significant differences in the body mass index, fecal moisture, gut transit time, and soy consumption frequency between the two soyasaponin degradation phenotypes. Two primary gut microbial metabolites of soyasaponin I were identified as soyasaponin III (3-O-[beta-D-galactopyranosyl-beta-D-glucuronopyranosyl]olean-12-ene-3beta,22beta,24-triol) and soyasapogenol B (olean-12-ene-3beta,22beta,24-triol) by NMR and electrospray ionized mass spectroscopy. Soyasaponin III appeared within the first 24 h and disappeared by 48 h. Soyasapogenol B seemed to be the final metabolic product during the 48 h anaerobic incubation. These results indicate that dietary soyasaponins can be metabolized by human gut microorganisms. The sugar moieties of soyasaponins seem to be hydrolyzed sequentially to yield smaller and more hydrophobic metabolites.     

电控发动机尾气检测与故障诊断的研究

为寻求根据汽车尾气参数来诊断汽车故障的方法，利用径向基函数（RBF）神经网络，对丰田雷克萨斯（LEXUS）400电控发动机进行故障诊断研究。研究结果表明，径向基函数神经网络对发动机故障的诊断是迅速、准确的。