1-MCP对猕猴桃后熟质地品质的临界浓度研究

为探究1-甲基环丙烯(1-MCP)对猕猴桃后熟质地品质作用效果的差异,寻找适宜的1-MCP临界使用浓度,研究通过应用质地多面分析(TPA)测试法,以"贵长"猕猴桃为试材,比较不同处理果肉质地品质差异和好果率,分析各质地参数之间相关性,并且用主成分分析法进行综合评价。结果表明:0.75μL/L和0.50μL/L 1-MCP处理均能够更好地保持猕猴桃货架期的好果率;果实的咀嚼性、弹性、硬度、回复性和凝聚性相互之间都有较好的相关性,但黏着性与其他指标相关性较差,所以用咀嚼性、弹性、硬度、回复性和凝聚性作为评价猕猴桃果实质购性能的主要参数。与对照比较,6种浓度1-MCP处理中,0.75μL/L 1-MCP的处理对维持猕猴桃后熟质地品质效果最好,其次是0.50μL/L1-MCP处理,两组处理均能够延缓果实硬度并且使果实正常后熟。而高浓度(1.50μL/L和1.25μL/L)的1-MCP对猕猴桃果实后熟质地的保持效果较差,出现"僵尸果"现象。另外综合主成分分析显示,货架末期(9 d)时,不同处理猕猴桃质地品质从高到低的排列顺序为:0.75μL/L0.50μL/L1.00μL/L0.25μL/L1.25μL/L1.50μL/L0μL/L。因此,从经济和后熟质地品质考虑,采后用0.50～0.75μL/L1-MCP来处理猕猴桃对保持果实质地品质的效果最好。     

Zinc biofortification of maize (Zea mays L.): Status and challenges

Zn deficiency is one of the leading health problems in children and women of developing countries. Different interventions could be used to overcome malnutrition, but biofortification is most impactful, convenient, sustainable and acceptable intervention. Maize is one of the major crops grown and consumed in the regions with prevalent Zn malnutrition; therefore, this is suitable target for Zn biofortification. Zn biofortification of maize could be achieved through agronomic and genetic approaches. Discussion of agronomic approaches with genetic approaches is prerequisite because soils in developing countries are deficit of Zn and availability of Zn in soils is mandatory for estimating the genetic responses of maize genotypes through genetic approaches. Seed priming, foliar and soil applications are agronomic tools for biofortification, but solo and combined applications of these treatments have different effects on Zn enrichment. Genetic approaches include the increase of Zn bioavailability or increase of kernel Zn concentration. Zn bioavailability could be increased by reducing the anti‐nutritional factors or by increasing the bioavailability enhancers. Kernel Zn concentration could be improved through hybridization and selections, whereas genetically engineered attempts for improving Zn uptake from soil, loading in xylem, remobilization in grains and sequestration in endosperm can further improve the kernel Zn concentration. Key challenges associated with dissemination of Zn biofortified maize are also under discussion in this draft. Current review emphasized all of above‐mentioned contents to provide roadmap for the development of Zn biofortified maize genotypes to curb the global Zn malnutrition.     

Influence of soil phosphorus status,texture, pH and metal content on the efficacy of amendments to pig slurry in reducing phosphorus losses

Cost‐effective strategies for using chemically amended organic fertilizers need to be developed to minimize nutrient losses in surface and groundwater. Coupling specific soil physical and chemical characteristics with amendment type could increase their effectiveness. This study investigated how water‐extractable phosphorus (P) was affected by chemical amendments added to pig slurry and how this effect varied with soil properties. A 3‐month incubation study was conducted on 18 different mineral soils, stored at 10 °C and 75% humidity and treated with unamended and amended slurry which was incorporated at a rate equivalent to 19 kg total P (TP )/ha. The amendments examined were commercial‐grade liquid alum, applied at a rate of 0.88:1 [Al:TP ], and commercial‐grade liquid poly‐aluminium chloride (PAC ), applied at a rate of 0.72:1 [Al:TP ]. These amendments were previously identified by the authors as being effective in reducing incidental losses of P. The efficacy of the amendments varied with the soil test P, the degree of P saturation (DPS ) and the Mehlich aluminium, iron and calcium, but not soil texture. Chemical amendments were most effective in soils with DPS over approximately 20%. Due to their high cost, the incorporation of amendments into existing management practices can only be justified as part of a holistic management plan where soils have high DPS .     

羊支原体性肺炎两标准株对抗菌药物敏感性的研究

本实验测定了环丙沙星、氧氟沙星、单诺沙星、红霉素、罗红霉素、泰勒菌素、泰妙菌素、四环素等8种药物对羊肺炎支原体两个标准株Y98和Y-goat的体外抑菌浓度以及红霉素与氧氟沙星、泰勒菌素对Y-goat和四环素与氧氟沙星、泰勒菌素对Y98的联合药敏作用。对羊肺炎支原体两个标准株对抗菌药物的敏感性进行了分析。     

Ionic Ratios and Crop Performance: II. Effects of Interactions amongst Vanadium, Phosphorus, Magnesium and Calcium on Soybean Yield

Because vanadium (V) is easily reduced to a cationic form within plant cells, data from resin-extraction of soil were analysed for evidence of interactions between V and the resin-extractable concentrations of magnesium (Mg) and calcium (Ca) on soybean seed yield. Three varieties, 9091, 9061 and 704, were grown over a 3-year period in a corn–soybean–wheat rotation. Surface soil samples (0–15 cm) were extracted with ion-exchange resins, extracts were analysed by inductively coupled plasma methods (ICP), and the results were regressed against seed yield using SAS PROC STEPWISE analysis using forward selection, backward elimination and maximum R² routines. The seed yield of each variety showed a correlation with a unique set of resin-extractable concentrations of V, phosphorus (P), Mg and Ca, and the V:(V + P), Mg:(Mg + Ca), Mg:(Mg + 1000 V) and Ca:(Ca + 1000 V) ratios. Variety 9091 was most sensitive to the Mg:(Mg + Ca) ratio. Variety 9061 was most sensitive to extractable V and to the V:(V + P) ratio. Variety 704 was sensitive to extractable P, V and Ca and the Mg:(Mg + 1000 V) ratio. For variety 9091, Mg fertilization (not currently practised) may be an economical practice, whereas P fertilization of 704 may not be economical. Each regression technique varied slightly in identification of important factors in seed yield. Concentrations and ratios of resin-extractable elements in soil provide insights into optimal genotype selection and possible management alternatives for a given soil.     

八种中草药体外抑制大肠杆菌的效果观察

选取马尾松、田基黄、艾草、雷公根、芭蕉芯、浮萍、野菊花、番石榴叶8种中草药，采用常规中草药药敏试验打孔法和试管法对猪大肠杆菌（K88）、大肠杆菌（0157）进行体外抑菌试验。结果显示，艾草、野菊花、番石榴叶对大肠杆菌呈高度敏感，其中艾草对大肠杆菌抑菌力最强；马尾松挥发油对大肠杆菌呈中度敏感；田基黄、雷公根、芭蕉芯、浮萍对大肠杆菌无抑菌作用。     

磷对奶牛红细胞膜脂质的影响

对１５例临床上有明显低磷血症的奶牛血清磷、红细胞膜脂质成分进行了测定。结果表明，低磷血症奶牛血清磷、红细胞膜磷脂明显降低；红细胞膜胆固醇及膜胆固醇／磷脂摩尔比值（ｎｃｈ／ｎｐｌ）明显升高，与健康对照组牛相比差异极显著（Ｐ＜０．０１）；直线相关分析表明，血清磷与红细胞膜磷脂之间呈极显著正相关（ｒ＝０．９１７，ｙ＝１０．８５２ｘ＋３．１９６，Ｐ＜０．０１）；与红细胞膜胆固醇以及ｎｃｈ／ｎｐｌ之间分别呈显著负相关（ｒ＝－０．９４０，ｙ＝２．８５０ｘ－１．０７２，Ｐ＜０．０１；ｒ＝－０．９２０，ｙ＝１．９６８ｘ－１．４０１，Ｐ＜０．０１）。此外，红细胞膜微粘度与膜磷脂之间呈显著负相关（ｒ＝－０．９５４，ｙ＝１９．１２２ｘ－４．３８４，Ｐ＜０．０１），而与膜胆固醇以及ｎｃｈ／ｎｐｌ之间呈显著正相关（ｒ＝０．９８８，ｙ＝０．９２７ｘ＋０．９６４，Ｐ＜０．０１；ｒ＝０．９７８，ｙ＝－０．２９３ｘ＋１．１１３，Ｐ＜０．０１）。结果表明，磷是红细胞膜脂质成分改变的先决因素，而后者又是红细胞膜流动性及膜结构、功能发生变化并导致膜损伤的一个重要因素。     

蒸发浓缩－CODcr法测定地面水中低浓度COD

对水样蒸发浓缩法用于地面水中低浓度ＣＯＤ的测定进行探讨的实验结果表明，地面水中低浓度ＣＯＤ物质可以在碱性条件下，通过蒸发浓缩处理后，采用重铬酸钾法进行测定，所得结果的精密度和准确度良好．若选择水样浓缩系数为５，则可将重铬酸钾法的最低检测限浓度降低到１０ｍｇ·Ｌ－１，从而使该方法能够适用于地面水水质标准中各类水质ＣＯＤ的监测要求．     

Nutrient digestibility of angling baits for carp, Cyprinus carpio, with implications for groundbait formulation and eutrophication control

Abstract  To evaluate the suitability of angling groundbaits as a fish feed and the potential for nutrient loss, the macronutrient digestibility of four groundbaits was investigated in carp, Cyprinus carpio L., using a sieving method of faeces collection and chromic oxide. Apparent digestibility coefficients (ADCs) of protein and lipids were >80% for all angling baits. ADCs of nitrogen-free extracts and phosphorus (P) differed significantly between the test diets, probably because of divergent feed compositions and ingredient treatments. The generally high digestibility estimates indicated that fish feeding on angling groundbait will benefit from this food source. The differences in nutrient digestibility suggested that type of groundbait and ingredient used will have a major effect on potential eutrophication and fish production caused by groundbaiting. The principle of groundbaits to protect the environment should be to minimise the P-content of the groundaits and maximising P-digestibility and P-retention efficiency.     

Stoffbildung, CO2-Gaswechsel, Kohlenhydrat- und Stickstoffgehalt von Winterweizen bei erhöhter CO2-Konzentration und Trocken-streß

Dry Matter Production, CO₂ Exchange, Carbohydrate and Nitrogen Content of Winter Wheat at Elevated CO₂ Concentration and Drought Stress
Methods of mathematical modelling and simulation are being used to an increasing degree in estimating the effects of rising atmospheric CO₂ concentration and changing climatic conditions on agricultural ecosystems. In this context, detailed knowledge is required about the possible effects on crop growth and physiological processes. To this aim, the influence of an elevated CO₂ concentration and of drought stress on dry matter production, CO₂ exchange, and on carbohydrate and nitrogen content was studied in two winter wheat varieties from shooting to milk ripeness. Elevated CO₂ concentration leads to a compensation of drought stress and at optimal water supply to an increase of vegetative dry matter and of yield to the fourfold value. This effects were caused by enhanced growth of secondary tillers which were reduced in plants cultivated at atmospheric CO₂ concentration. Analogous effects in the development of ear organs were influenced additionally by competitive interactions between the developing organs. The content and the mass of ethanol soluble carbohydrates in leaves and stems were increased after the CO₂ treatment and exhausted more completely during the grain filling period after drought stress. Plants cultivated from shooting to milk ripeness at elevated CO₂ concentration showed a reduced response of net photosynthesis rate to increasing CO₂ concentration by comparison with untreated plants. The rate of dark respiration was increased in this plants.