秸秆施用后土壤溶解性有机质的动态变化

采用室内培养方法研究了水稻秸秆腐解对土壤溶解性有机质（Dissolved Organic Matter,DOM）含量及其化学组成的动态影响。结果表明,秸秆腐解的前7 d显著增加了土壤溶解性有机碳（DOC）含量,7 d后则无明显影响;同时,秸秆腐解增加了土壤中溶解性糖（DS）、溶解性酚酸（DP）以及芳香族化合物含量。随着腐解时间的延长,溶解性糖在DOC中所占比例下降,而芳香族化合物逐渐上升,表明秸秆腐解不同阶段DOM的化学组成发生了变化。溶解性总氮（TDN）的变化表明,秸秆腐解增加土壤氮素的固定。     

不同菌株发酵枸杞汁中生物活性物质与香气组成物质含量变化

为研究枸杞汁经过不同菌株发酵后品质与挥发性成分的变化,采用酵素食品中分离的4株菌分别发酵枸杞汁,比较不同发酵枸杞汁的黄酮、蛋白质、总酚和挥发性成分等产品特性。结果表明:各菌种发酵液中黄酮含量均有显著增加;蛋白质和总酚含量差异显著,罗伊氏乳杆菌(Lactobacillus reuteri)发酵液蛋白质含量最高,为(599.50±1.53)μg·mL^-1,巴达维亚芽孢杆菌(Bacillus bataviensis)发酵液含量最低,为(168.11±1.00)μg·mL^-1;总酚含量最高的是巴达维亚芽孢杆菌(Bacillus bataviensis)发酵液,为鼠李糖乳杆菌(Lactobacillus rhamnosus)、地衣芽孢杆菌(Bacillus licheniformis)、罗伊氏乳杆菌(Lactobacillus reuteri)发酵液总酚含量的1.10～3.01倍。各菌种发酵液共检测到挥发性成分52个,其中共有成分24个,但含量在各菌种发酵液中存在显著差异,酸类物质对发酵后的枸杞汁风味影响较大。综合各个指标,4种菌株中的Bacillus...     

Effects of Nutrient and NaCl Salinity on Growth,Yield, Quality and Composition of Pepper Grown in Soilless Closed System

The effects of nutrient or sodium chloride (NaCl) salinity on pepper grown in closed soilless culture systems were studied. A control (2 dS m^?1) and two saline nutrient solutions (4 dS m^?1) differing in the salt sources (fertilizers or NaCl) were studied. Shoot biomass production as well as total and marketable yield were more affected by NaCl than nutrient salinity. Fruit dry matter and total soluble solids increased in both salinity treatments compared to the control. Total phenol content rose slightly (10%) with NaCl salinity, while the concentration of carotenoids was enhanced by 40% with NaCl compared to the control and nutrient salinity. The results showed that the response of pepper to salinity is both osmotic and ion specific, but a more negative effect was recorded under NaCl stress. Moreover, the highest content of antioxidant compounds in NaCl treated fruits may indicate that NaCl caused more stressful conditions than nutrient salinity.     

Biotest— and chemistry-based hazard assessment of soils,sediments and solid wastes

Background and Objectives  The current environmental legislation regulating pollution issues is based on total levels of pollutants. This approach is not taking into account the bioavailability of pollutants (that is especially important for an analysis of soils and sediments as heavy metals and hydrophobic organic toxicants tend to sorb to solid matrix) and effects of toxicants in mixtures. Thus, toxicity-based criteria should be added to the currently existing chemical ones for the meaningful evaluation of the environmental hazard. The aim of the current study was 1) to compare the ecotoxicity and chemistry-based environmental evaluations for 27 solid-phase environmental samples (soils, sediments, solid wastes); 2) to suggest the battery of biotests for the screening of water-extracted toxicity. Methods  14 soils, 9 sediments and 4 oil-shale industry solid waste samples from Estonia and Lithuania were analyzed for the concentration of total PAHs, heavy metals, oil products and water-extracted phenols. The pollution level was evaluated by comparison of measured concentrations with Estonian permitted limit values in residential (PLV_r) and industrial (PLV_i) areas for each key pollutant A battery of 8 aquatic toxicity tests was applied for the analysis of aqueous extracts (L/S=3) of samples: tests with microalgaeSelenastrum capricornutum, macroalgaeNitellopsis obtusa, protozoaTetrahymena thermophila, crustaceansDaphnia magna andThamnocephalus platyurus, rotifersBrachionus calyciflorus and photobacteriaVibrio fiscberi. Particle-bound bioavailable toxicity was evaluated using a kinetic photobacterial assay withVibrio fiscberi (Solid-Phase Flash-Assay). The toxicity data were evaluated by MaxTox index (highest toxic signal of the battery). Results  Chemical evaluation and toxicological evaluation pointed to the same direction in half of the cases (13/27): 5 samples (including 2 presumably clean control soils) proved harmless and 8 hazardous to environment in case of both evaluations. However, there was a disagreement between chemical and toxicological evaluations for the rest of the samples (14/27). In two mismatching cases (soils from the territory of former gasoline stations) the level of oil products exceeded the PLV_r, but no toxicity was detected, most probably due to the low bioavailability of aged pollutants. It must be taken as a warning that a majority of mismatching cases (12/14) of the samples proved to be toxic or even very toxic despite the fact that the measured hazardous key pollutant levels were below the PLVr. Within these 12 samples were 2 soils from municipal dumping sites, 2 soils from the territory of military airport, 6 sediments from Curonian lagoon (Lithuania) and 2 oil-shale industry solid wastes (Estonia). Conclusions  The results of this study show the necessity of biotesting in environmental risk assessment to avoid the falsenegative results that may result in harmful effects for the ecosystems and also to human health. The following, reduced test battery was proposed for the ecotoxicological hazard assessment of water-extractable toxicity of solid-phase samples:Tetrahymena thermophila growth inhibition assay,Daphnia magna mortality assay andSelenastrum capricornutum growth inhibition assay. Also, the Microtox test (Vibrio fiscberi luminescence inhibition assay) could be valuable for screening purposes. For the evaluation of particle-bound, bioavailable toxicity of soil suspensions, Solid-Phase Flash-Assay (test organismVibrio fiscberi) is suggested. Compared to the results obtained with the initial battery of 8 tests, the reduced battery detected the toxicity in 85% of the cases.     

Photodegradation effects on CO2 emissions from litter and SOM and photo-facilitation of microbial decomposition in a California grassland

Decomposition of soil organic matter (SOM) and plant litter has been shown to be affected by high solar radiation; this could partly explain why biogeochemical models underestimate decomposition in arid and semi-arid ecosystems. We set out to test the effect of using traditional PVC chambers for measuring soil gas fluxes versus quartz chambers that allowed passage of light during field measurements in a dry-land field in Davis, CA. Results showed that fluxes from quartz-top chambers were on average 29% higher than from opaque chambers. We also studied the effect of solar light exposure on decomposition of native grass litter and SOM in a field experiment where plots were shaded or left exposed for 157 days during summer; litter did not seem to be affected by exposure to light. However, we concluded that SOM decomposition was affected by light exposure since shaded soil had similar respiration to sunlight-exposed soil indicating that microbial respiration occurred under the shade while photo-degradation likely occurred under the sun. Additionally, ¹⁵N-labeled grass was placed in litter bags in the field with either clear filters to allow light or aluminum covers to block light; 3-month exposure caused a change in lignin degradability as indicated by the change in the Ad/Al ratio. Incubation of that litter showed 9.3% more CO₂ produced from litter in clear and aluminum bags than unexposed litter. This showed that photo-facilitation occurred although to a small degree and was a result of light exposure and/or heat degradation. We attributed the similar respiration from clear- and aluminum-exposed litter to heat degradation of the aluminum-exposed litter. In conclusion, our results show that in hot dry ecosystems conventional PVC chambers underestimate measured CO₂ flux rates; sunlight exposure changes litter chemistry and appears to affect the degradation of soil organic matter, but the magnitude of degradation depends on an interaction of factors such as soil temperature and moisture.     

茶叶添加方式对酿造啤酒理化特性及感官品质的影响

在啤酒酿造工艺的煮沸和主发酵阶段分别添加乌龙茶,探讨茶叶不同添加方式对啤酒理化特性、抗氧化能力、啤酒贮存稳定性以及感官特性的影响.结果显示,与未添加茶叶的啤酒产品(对照组CG)相比,在煮沸阶段(煮沸添加组BG)和主发酵阶段(主发酵添加组MG)分别添加0.3 g/L的茶叶均提高了酵母发酵速率;添加茶叶的两个茶啤酒产品(煮...     

柿果实单宁细胞特征与总酚和缩合单宁含量的关系

In this study,51 accessions of mature persimmon fruits were used as materials to investigate the correlation between characteristics of tannin cells,and total phenolics and condensed tannins contents. ...     

Feeding dihydroquercetin to broiler chickens

1. A total of 80 male Ross 308 broilers were used in a study to investigate the effect of dietary dihydroquercetin (DHQ) on growth performance variables, gastrointestinal tract (GIT) and immune organ development, glutathione peroxidase (GPx) and haemoglobin in blood, hepatic vitamin E content, dietary N-corrected metabolisable energy (AMEn) and nutrient retention coefficients when fed to broiler chickens from 7 to 35 d of age.

2. Two treatments were used in this study: control (C) and C + 0.5 g/kg extract of Siberian Larch (Larix sibirica) per kg feed, containing 85% DHQ. The diets were fed over 2 feeding phases, a grower phase from 7 to 28 d of age and a finisher phase from 28 to 35 d of age. The birds were reared under the breeder’s recommended conditions.

3. In general, there were no effects of DHQ on growth performance of broiler chickens. However, the results of this experiment showed that there can be changes in the redness colour of the breast meat when DQH is fed. No negative effects of feeding DHQ at 0.5 g/kg diet were observed in this study.

4. Supplementation of poultry diets with DHQ under standard industry-rearing conditions did not improve the performance or any of the studied variables, except an increase of redness index of the breast fillets. Feeding DHQ at different doses and/or under more challenging conditions, e.g. heat stress, may, however, bring positive responses.     

Qualitative profile of degummed guar (Cyamopsis tetragonoloba L.) seeds grown in a Mediterranean area for use as animal feed

Guar (Cyamopsis tetragonoloba L.) is an interesting summer legume multipurpose crop used for the extraction of seed gum, due to its galactomannan content, and the high‐protein by‐product, (germ and hull) used for animal feed. The aim of this study was to assess qualitative traits of degummed seeds, named guar meal, of six guar varieties from India, South Africa and USA, grown in a Mediterranean environment (Sicily, Southern Italy), in order to explore their suitability for livestock, and comparing them with the marketed Indian products of guar meals, Churi and Korma. After harvest, seeds were manually degummed and proximate composition was analysed using the official method of analyses, total phenols and tannins by UV spectrophotometry and fatty acids by GC‐FID. Qualitative profile of degummed guar seeds (DGS) was significantly (p < .05) influenced by the genotype. Among DGS, Matador showed a high (p < .05) content of protein (518 g/kg), lipids (59.4 g/kg) and the lowest (p < .05) NDF level (181 g/kg) compared to the other varieties. Total phenol content of DGS showed similar values among varieties (2.57 mg gallic acid/g, on average) and with those of guar meal Korma 50%–53% (2.89 mg gallic acid/g) and Korma 56%–58% (2.94 mg gallic acid/g). Tannins were below the instrumental limit of quantification (1.5 mg/g of catechin equivalents) in DGS, as well as in the marketed products. Fatty acid composition was significantly influenced (p < .05) by the genotype. Matador showed the significant highest content of polyunsaturated fatty acids (PUFA) of the n6 series (45.2 g/100 g), whereas India showed the significant (p < .05) highest content of PUFA of the n3 series (3.55 g/100 g), and the significant (p < .05) highest level of n3/n6 PUFA ratio (0.08), and the best (p < .05) Atherogenic Index (0.19) and Thrombogenic Index (0.46). This study shows the interesting nutritional characteristics of degummed guar seeds, underlining that, if the future of the guar gum industries depends largely on the utilization of guar seed meal, this product can be considered a valuable feed resource and a way to increase the income of guar production.     

蝴蝶兰组培褐变与酚酸类物质及相关酶活性的关系

 【目的】寻找与蝴蝶兰褐变相关的主要酚酸,并了解与总酚含量及相关酶活性之间的关系。【方法】以3个褐变程度不同的蝴蝶兰品种P.‘China Best Girl’（A1）、P. amabilis BL.‘Jude Butterfly’（B3）和Dtps. King Shiang’s Rose×Jetgreen Firbird (R4)为材料,利用高效液相色谱对其进行了9种酚酸的定性定量分析,并在以叶片为外植体的初代培养过程中,研究了总酚含量、苯丙氨酸解氨酶（PAL）、多酚氧化酶（PPO）和过氧化物酶（POD）的动态变化。【结果】初步证明绿原酸、邻苯二酚、儿茶酚、咖啡酸及没食子酸、对羟基苯甲酸、香豆酸可能与蝴蝶兰褐变相关,苯甲酸对蝴蝶兰褐变影响很小;在褐变过程中,褐变程度高的品种,总酚含量也高;PAL和PPO活性与褐变程度呈正相关,POD与褐变有很大关系;总酚含量与PAL活性呈正相关,与PPO和POD活性呈负相关。【结论】初步阐明了与蝴蝶兰褐变相关的酚酸种类,以及褐变程度与总酚含量及相关酶活性的关系。