香味剂桂皮香对育肥猪采食量及采食行为的影响

试验选择体重相近的75日龄育肥猪18头,随机分为3个重复,每个重复6头猪.同一圈合同时放置试验日粮和对照日粮,对照组饲喂基础日粮,试验料槽A、B和C中在基础日粮中分别添加香味剂桂皮香300、500、800 g·t-1.每天记录日采食量和采食时间.考察香味剂桂皮香对猪采食量及采食行为的影响.结果显示,香味剂桂皮香具有提高育肥猪采食次数、采食时间和采食速度的作用.     

Dynamics of Forms of Inorganic Phosphorus in Soil under Coffee Plants as a Function of Successive Annual Additions of the Nutrient

Phosphorus (P) dynamics and availability in soils are influenced by P fertilization. This paper aimed to evaluate inorganic P fractions bonded to calcium (Ca), iron (Fe), and aluminum (Al), associating them with soil mineralogy. The experiment was carried out using an acidic kaolinitic–oxidic soil, located in an irrigated area cultivated with coffee plants (Coffee arabica L.), submitted to successive annual fertilizations with triple superphosphate doses of 0, 50, 100 200, and 400 kg ha^?1 phosphorus pentoxide (P₂O₅) in randomized blocks with three replications. Phosphorus fractions were determined in soil samples collected at two depths, 0–10 and 10–20 cm, according to the methodology used by Chang and Jackson (1957 Chang, S. C. and Jackson, M. L. 1957. Fractionation of soil phosphorus. Soil Science, 84: 133–144. [Crossref] , [Google Scholar]). The inorganic P fractions presented the following sequence: P-Al > P-Fe > P-Ca. The dynamics of forms of inorganic P showed that P-Al is controlling the P bioavailability as a result of an acidic pH and a very simple and thermodynamically stable clay mineralogy, typical of very weathered and old tropical soils.     

Overcoming the Confounding Effects of Salinity on Sodic Soil Research

The adverse effects of sodicity on plant growth are difficult to quantify using naturally occurring soils because of the confounding variation in other soil properties, particularly salinity, pH, organic matter, soil nutrients, mineralogy, and texture. We applied a method involving the equilibration of large soil volumes with solutions varying in sodium adsorption ratio (SAR), followed by excess salt removal with solutions of similar SAR but lower ionic strength. Application of this method to a calcareous nonsodic, nonsaline Vertosol from Narrabri, New South Wales, resulted in soils with exchangeable sodium percentage (ESP) values between 2% and 25% but with similar magnesium and potassium concentrations and constant electrical conductivity (～2.7 dS/m). Soil pH and solution phosphorus concentrations automatically increased as the ESP of the soil rose, which is important to consider when addressing plant growth results. This method can successfully minimize the confounding of sodicity with other soil properties that so often plagues sodic soil research.     

Chemical Speciation of Heavy Metals in the Fractionated Rhizosphere Soils of Sunflower Cultivated in a Humic Andosol

Chemical speciation and bioaccumulation factor of iron (Fe), manganese (Mn), and zinc (Zn) were investigated in the fractionated rhizosphere soils and tissues of sunflower plants grown in a humic Andosol. The experiment was conducted for a period of 35 days in the greenhouse, and at harvest the soil system was differentiated into bulk, rhizosphere, and rhizoplane soils based on the collection of root-attaching soil aggregates. The chemical speciations of heavy metals in the soil samples were determined after extraction sequentially into fractions classified as exchangeable, carbonate bound, metal–organic complex bound, easily reducible metal oxide bound, hydrogen peroxide (H₂O₂)–extractable organically bound, amorphous mineral colloid bound, and crystalline Fe oxide bound. Iron and Zn were predominantly crystalline Fe oxide bound in the initial bulk soils whereas Mn was mainly organically bound. Heavy metals in the exchangeable form accumulated in the rhizosphere and rhizoplane soils, comprising <4% of the total content, suggesting their relatively low availability in humic Andosol. Concentrations of organically bound Fe and Mn in soils decreased with the proximity to roots, suggesting that organic fraction is the main source for plant uptake. Concentrations of Mn and Zn in the metal–organic complex also decreased, indicating a greater ability of sunflower to access Mn from more soil pools. Sunflower showed bioaccumulation factors for Zn, Fe, and Mn as large as 0.39, 0.05, and 0.04 respectively, defining the plant as a metal excluder species. This result suggests that access to multiple metal pools in soil is not necessarily a major factor that governs metal accumulation in the plant.     

两种菠萝鲜果及其酿造果酒酯类风味物质差异性分析

以"神湾"和"粤彤"两种菠萝为材料,分别对其鲜果及酿造的干酒和蒸馏酒的酯类风味物质进行比较分析.结果 表明:"粤彤"鲜果中酯类风味物质组分数及总相对含量均高于"神湾";与鲜果相比,"神湾"和"粤彤"酿造的干酒中酯类风味物质组分数增多,但总相对含量降低;与鲜果和干酒相比,"神湾"和"粤彤"酿造的蒸馏酒中酯类风味物质组分数减少,总相对含量降低;"神湾"和"粤彤"鲜果、干酒和蒸馏酒中同时检测出的酯类风味物质有己酸乙酯和辛酸乙酯,"神湾"鲜果及干酒和蒸馏酒中己酸乙酯的相对含量分别高于"粤彤","神湾"鲜果及蒸馏酒中辛酸乙酯的相对含量分别高于"粤彤".本研究可为菠萝酿酒加工中果实来源选择提供参考.     

生物专业的有机化学在独立学院的教学探讨

针对独立学院生物专业的有机化学理论教学学时较少且学生学习基础相对薄弱的教 学实际情况,通过采用多样化的教学方法,同时应用网络信息技术教学手段,优化和整合有机化 学的教学内容,与科研相结合等几个方面进行有机化学的教学改革,提高了学生的学习积极性, 使有机化学的教学效果得到提升,为学院的应用型人才培养目标奠定坚实的知识基础。     

复烤温度对西南清香型烟叶质量的影响

研究了复烤温度(80、85、90℃)对云南和四川烟区中、上部清香型烟叶的常规化学成分、致香成分和感官评吸的影响。结果表明:随着复烤温度升高,中部烟和B2F的总糖和还原糖含量升高,中部烟的糖碱比升高,复烤温度对烟叶总植物碱、总氮和氮碱比的影响较小;复烤温度在80~85℃时,烟叶致香成分中的质体色素降解产物、美拉德反应产物和西柏烷类物质的含量较高,烟叶香气质、香气量、刺激性、杂气、余味及香韵等方面有较好的表现,中上部烟叶的复烤温度控制在80~85℃为宜。     

不同品种樱桃番茄氨基酸组成及风味分析

为评价不同品种樱桃番茄的风味及营养价值,比较分析了8个品种樱桃番茄的可溶性固形物含量、总糖含量、有机酸含量、糖酸比、Vc含量、氨基酸含量和氨基酸组成。结果表明,红果樱桃番茄品种的部分风味指标(可溶性固形物、总糖、有机酸、Vc)、氨基酸组成及营养价值(总氨基酸、必需氨基酸含量及氨基酸模式谱)优于黄果品种,尤其是红果品种浙樱粉1号和浙樱红1号,其中,浙樱粉1号樱桃番茄可溶性固形物含量、总糖含量、有机酸含量、Vc含量、呈味类氨基酸(鲜味、甜味、芳香类)含量及氨基酸营养价值均处于较高水平。红果樱桃番茄品种之间的总糖含量、Vc含量,以及黄果樱桃番茄品种之间的有机酸含量、总氨基酸含量、必需氨基酸含量和甜味类氨基酸含量等指标均呈现出较低的变异系数。氨基酸营养价值分析表明,缬氨酸和亮氨酸是樱桃番茄的2个主要限制氨基酸。本研究结果为高品质樱桃番茄的品种选育提供了理论指导。     

饲粮甘草茎叶水平对阿勒泰羊羊肉风味的影响

旨在研究饲粮甘草茎叶水平对育肥期阿勒泰羊羊肉肌酐酸、硫胺素、胆固醇、脂肪酸和氨基酸的影响,探讨育肥期阿勒泰羊饲粮中甘草茎叶的适宜添加水平。选取体质量为40 kg的6月龄健康阿勒泰羊60只,随机分为6组,每组10只羊。分别饲喂6种甘草茎叶添加水平不同的等能等氮试验饲粮(对照组Ⅰ组甘草茎叶添加水平为0.00%,试验组Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅵ组甘草茎叶添加水平分别为10.01%、14.95%、20.41%、29.98%、60.11%)。试验期为60 d。结果表明:除了Ⅵ组羊肉背最长肌中硫胺素质量分数显著低于对照组(P0.05)外,其他各组与对照组差异不显著(P0.05)。虽然不同甘草茎叶添加水平对背最长肌中肌苷酸和胆固醇的质量分数影响不显著(P0.05),但Ⅳ组肌苷酸质量分数最高,比对照组提高了20.67%,而胆固醇质量分数最低,比对照组降低了45.33%。与对照组比较,Ⅲ组背最长肌中二十碳二烯酸的质量分数极显著降低(P0.01),二十一碳烯酸和二十二烷酸的质量分数显著降低(P0.05),其他各组差异均不显著(P0.05);从背最长肌中主要的饱和脂肪酸硬脂酸来看,Ⅳ组降低程度最大,降低了10.55%;从主要的不饱和脂肪酸油酸来看,Ⅲ组增加幅度最大,增加了5.54%;而从必需脂肪酸亚麻酸来看,仅有Ⅳ组有所增加;Ⅴ组的总饱和脂肪酸质量分数低于其他各组,而总不饱和脂肪酸质量分数高于其他各组。与对照组比较,Ⅵ组极显著降低了背最长肌中蛋氨酸质量分数(P0.01),Ⅲ组显著降低了背最长肌中酪氨酸质量分数(P0.05);而Ⅳ组背最长肌中丝氨酸、丙氨酸、缬氨酸、异亮氨酸、亮氨酸、天冬氨酸和氨基酸总量均显著高于Ⅵ组(P0.05),但与对照组及其他甘草茎叶添加组间并无显著差异(P0.05),此外,Ⅳ组背最长肌中谷氨酸、天冬氨酸和丙氨酸的质量分数均高于其他各组。由此可见,Ⅳ组有利于改善羊肉背最长肌中肌苷酸、胆固醇、风味氨基酸和人体必需脂肪酸的质量分数;Ⅳ和Ⅴ组有助于提高羊肉背最长肌中不饱和脂肪酸和必需脂肪酸的质量分数;综合考虑,20.41%甘草茎叶添加水平最佳,29.98%甘草茎叶添加水平次之。