Effect of supplementation with grain, hay or straw on the performance of weaner Merino sheep grazing old man (Atriplex nummularia) or river (Atriplex amnicola) saltbush

Old man saltbush ( Atriplex nummularia ) and river saltbush ( A. amnicola ) are widely used in commercial grazing systems on saline land in south-western Australia. Three hypotheses were tested during a 3-year study aimed at understanding the performance of weaner Merino sheep grazing saltbush-based pastures. The first hypothesis, that young Merino sheep grazing river saltbush would be better able to maintain live weight, body condition and would grow more wool than sheep grazing old man saltbush, was not supported by the data. Across the 3 years of the study, sheep grazing old man saltbush lost significantly less live weight and grew more wool (proportionately 0·06) than sheep grazing river saltbush. Differences in animal performance were considered to be associated with differences between the plant species in in vitro digestibility, concentrations of fibre, sulphur and crude protein in the herbage and the architecture of the Atriplex plants. The second and third hypotheses concerned supplementation strategies for sheep grazing saltbush. Three supplements were offered, namely barley grain, cereal straw or cereal hay, at a rate that approximated to one-third of the daily metabolizable energy requirements for maintenance of live weight. The performance of the sheep was higher when the grain supplement was offered but there was no effect of feeding roughage supplements compared to no supplementation. The findings suggested that the practice of feeding saltbush with adjacent crop stubbles is unlikely to be beneficial once any fallen grain has been consumed.     

糖皮质激素抗炎替代品药理作用的研究

用实验药理学方法,对糖皮质激素醋酸泼尼松与糖皮质激素抗炎替代品(以下简称抗炎替代品)的药理作用和对巨噬细胞功能的影响,在同等试验条件下进行了比较研究。结果表明:两者对二甲苯所致家兔耳廓炎症的抑制率抗炎替代品低剂量组为25%,高剂量组为70 8%(P<0 01),醋酸泼尼松组为16 7%;对家兔蛋清性足跖的平均肿胀率,抗炎替代品低剂量组为(5 74±4 3)%,高剂量组为(3 46±3 4)%,醋酸泼尼松组为(10 14±4 5)%;对家兔棉球肉芽组织增生的抑制率抗炎替代品低剂量组为2 8%,高剂量组为10 4%(P<0 05),醋酸泼尼松组为8 3%;对家兔腹腔巨噬细胞吞噬鸡红血球的平均吞噬率抗炎替代品低剂量组为(83 7±4 3)%,高剂量组为(74 5±1 0)%,醋酸泼尼松组为(54 8±4 8)%.试验数据表明:两者均有抗炎作用,其中抗炎替代品作用较强,且对家兔腹腔巨噬细胞吞噬功能没有明显的影响。     

Limiting factors for reforestation of mine spoils from Galicia (Spain)

Mined areas are a continuing source of heavy metals and acidity that move off site in response to erosion. Revegetation of the mine tailings could limit the spread of these heavy metals and acidity. This study was conducted to evaluate, at four tailings on opencast mines of Galicia (Touro: copper mine; and Meirama: lignite mine, NW Spain), the chemical and physical soil quality indicators and limiting edaphic factors concerning forest production. Selected zones were: (1) The tailings formed by the waste materials from the depleted Touro mine; (2) the decantation site of deposited sludge coming from the copper extraction in the flotation stage; (3) and (4) tailings of 3 and 10 years old of the Meirama lignite mine. The main physical limitations of the mine soils are the low effective depth (<50 cm), high stoniness (>30 per cent) and high porosity (>60 per cent); which make them vulnerable to soil erosion and seriously interferes with the forest production. Soils coming from the decantation site of copper mine do not have physical limitations. The main chemical limitations of mine soils are their acidity (pH from 3·62 to 5·71), and aluminium saturation (>60 per cent in copper mine soils, and >20 per cent in lignite mine soils), low CECe (from 5·34 to 9·47 cmol₍₊₎ kg⁻¹), organic carbon (from 0·47 to 7·52 mg kg⁻¹) and Ca²⁺ and Mg²⁺ contents, and imbalance between exchange bases. Mine soils coming from the decantation site of copper mine soils are strongly limited by the high Cu content (1218 mg kg⁻¹). Lime and organic amendments are the most important factors in providing a suitable medium for plant growth. Copyright © 2004 John Wiley & Sons, Ltd.     

高胚胎再生能力大豆品种的筛选和培养方法改进

应用离体培养的方法,从本地10个,巴西5个和美国2个合计17个大豆品种中筛选出廉江、浙春、Perry、BRS0r7和Chief等5个体细胞胚胎再生能力强的品种,并在此基础上对这5个品种的培养基生长素浓度进行优化,对于廉江、浙春、Perry和BRS,最合适的2,4-D质量浓度为2mg／L,而对于Chief的最合适质量浓度为5mg／L,此外,在以Perry和BRS 07为材料进行的另一个试验中发现,当同为5mg／L的硫酸铜和硝酸银同时添加到培养基时对促进体细胞胚胎的形成具有协同作用。     

国产和进口阳离子交换树脂膜埋置法测定土壤中的有效钾

采用20个来自中国各地的土壤样品,研究了进口和国产阳离子交换树脂膜埋置法测定土壤中的有效钾的技术,结果表明阳离子交换树脂膜埋置法测定土壤有效钾的最佳埋置时间为20min。树脂膜法测定的土壤钾值与中性醋酸铵法测定的土壤有效钾之间具有极显著的相关性,进口树脂膜的测定值与中性醋酸铵法测定值间的相关性稍优于国产树脂膜。中性醋酸铵法和树脂膜法测定的土壤钾与植物实际吸钾量间具有极显著的相关性。树脂膜法测定值与植物实际吸钾量间的相关性明显优于中性醋酸铵法．进口树脂膜稍优于国产树脂膜。     

环境因素对小麦苗期SOD、MDA及可溶性蛋白的影响

采用盆栽试验 ,模拟干旱胁迫、铜污染 (三级农田 )及不同施肥状况 ,测定了小麦苗期的生物量及叶片中的 SOD活性、MDA和可溶性蛋白含量。结果表明 ,水分、铜污染和施肥三因素对小麦苗期的生物量都有显著影响 ,表现为水分 >施肥 >铜污染 ;水分对 MDA含量的影响大于铜污染和施肥 ,表现为干旱可显著增大叶片 MDA含量 ,并使 MDA/SOD值增大 ;对 SOD和可溶性蛋白 ,水分和铜污染的影响大于施肥的影响 ,表现为干旱胁迫下 ,SOD活性升高 ,可溶性蛋白含量降低 ,而铜污染处理使可溶性蛋白含量升高 ;3种环境因素之间存在交互作用     

铝合金中铁,铜二元素同时测定的新方法

采用一种新的同时测定多组分的方法,即比值光谱导数分光光度法,在ｐＨ５．５缓冲溶液中,利用金属离子—５—Ｂｒ—ＰＡＤＡＰ—ＯＰ三元络合物显色体系,对铝合金中的Ｆｅ（Ⅱ）、Ｃｕ（Ⅱ）二组分进行了同时测定。各八次测定的相对标准偏差分别为１．６９％、３．６６％和３．８８％,２．５３％。     

Differences in susceptibility of Agaricus bisporus strains to bacterial blotch and in natural cap colour related to compost composition

The influence of cultivation substrate (compost) quality as an environmental factor was determined on three traits of interest in the selection of Agaricus bisporus strains. Induced variations in compost nitrogen and copper content were used to modify compost quality. Compost effect and strain × compost interaction were found to be significant for bacterial blotch susceptibility, natural cap colour and yield. Two classes of strain not affected by compost quality were identified in a group of commercial and wild strains: white mushrooms susceptible to bacterial blotch and brown resistant mushrooms. The relation between compost composition quality and mushroom quality traits are specific for each group of strain. Nitrogen and copper content of composts were of interest as indicators of compost quality but other factors have to be evaluated for better compost characterization.     

铜和镉对草鱼肾脏中3种白细胞介素基因表达的影响

为探讨水体铜(Cu)和镉(Cd)污染对草鱼免疫系统的影响,本研究利用实时荧光定量PCR(QRT-PCR)技术,分析在不同时间(2、4、6、8 d)及不同质量浓度的Cu²⁺(0.10、0.20、0.40、0.60、0.80 mg/L)和Cd²⁺(0.05、0.10、0.20、0.30、0.40 mg/L)暴露下,草鱼肾脏中3种白细胞介素——白细胞介素-1β、白细胞介素-8和白细胞介素-10基因表达量的变化。试验结果显示,高质量浓度和长时间的Cu²⁺暴露(0.60、0.80 mg/L, 8 d)和Cd²⁺暴露(0.20、0.30、0.40 mg/L, 8 d)下,草鱼肾脏中的白细胞介素-1β、白细胞介素-8和白细胞介素-10基因表达量与对照组相比显著增加(P<0.05);在0.80 mg/L Cu²⁺,0.30、0.40 mg/L Cd²⁺暴露下的草鱼肾脏中白细胞介素-1β的基因表达量,以及在0.60、0.80 mg/L Cu²⁺暴露下的草鱼肾脏中白细胞介素-8和白细胞介素-10的基因表达量,均随着暴露时间的增加而逐渐升高,且第8 d时的基因表达量均显著高于第2 d时(P<0.05)。本研究揭示了高质量浓度和长时间的Cu²⁺、Cd²⁺暴露会使草鱼肾脏产生炎症反应,为进一步深入研究重金属对鱼类的免疫毒性机制奠定了基础。     

Quantitative dietary copper requirement of juvenile Siberian sturgeon,Acipenser baerii,and effects on muscle composition and some enzymatic activities

An 8‐week feeding trial was conducted to quantify dietary copper (Cu) requirement of juvenile Siberian sturgeon, Acipenser baerii. Five isonitrogenous diets were formulated to provide actual dietary copper values of 1.8, 5.7, 10.1, 15.9 and 28.3 mg Cu per kg diet. Experimental diets were fed to the Siberian sturgeon (27.57 ± 0.24 g) in triplicate to apparent satiation for 8 weeks. At the end of experiment, weight gain (WG), specific growth rate (SGR) and protein efficiency ratio (PER) were significantly increased with increasing dietary Cu level up to 10.1 mg/kg and then decreased with further increases in dietary Cu level (p < .05). The Cu concentration in the liver and cartilage was positively correlated with the respective concentrations in the diet (p < .05), while muscle and serum Cu concentrations remained significantly unchanged (p > .05). Superoxide dismutase and glutathione peroxidase had the highest activities in serum of fish fed with 15.9 and 28.3 mg Cu per kg diet, respectively. Analysis by the broken‐line regression of SGR, crude protein content and superoxide activity demonstrated that the optimum dietary Cu requirements in juvenile Siberian sturgeon were 9.51, 9.58 and 16.10 mg/kg diet, respectively.