香石竹试管苗对营养物质吸收消耗规律

为加快香石竹试管苗的繁殖速度，对培养基中营养物质的变化进行了研究。结果表明，香石竹试管苗吸收磷，氮符合幂函数曲线，培养过程中培养基的糖含量直线下降，通过回归分析，培养基中ＰＯ４＾３－，ＮＨ４＾＋，ＮＯ３＾－，总氮与糖的含量对其培养时间的回归系数分别为－０．９４９０，－０．９０９０，－０．９４００，－０．９０６０，经统计检测都达到极显著水平，试管苗高生长与鲜重增长遵循双曲线函数关系，而丛生芽分化遵循     

Digesta characteristics in relation to nutrient digestibility and mineral absorption in Nile tilapia (Oreochromis niloticus L.) fed cereal grains of increasing viscosity

Soluble non-starch polysaccharides (NSP) present in cereal grains may affect performance of Nile tilapia through changes in digesta characteristics. The objective of this study was to investigate whether dietary cereal grains of increasing viscosity induce changes in digesta viscosity, dry matter and volatile fatty acids (VFA) and if these changes explain differences in nutrient digestibility and mineral absorption. Four experimental diets were formulated by adding 40% grains to a basal diet to obtain a range of dietary viscosities, increasing in the order of maize, barley, wheat and rye. The diets were assigned to 16 tanks with 40 fish (mean weight 70 g) each. Digesta viscosity increased with increasing grain viscosity (P < 0.001), whereas digesta dry matter decreased with increasing grain viscosity (P < 0.05). No significant differences were found among diets in total concentration and type of VFA. Nutrient digestibility was not significantly correlated with digesta viscosity. Of all nutrients, only starch digestibility was significantly negatively correlated with digesta dry matter in the middle intestine (r = − 0.57; P = 0.03). Absorption of sodium was significantly negatively correlated with digesta viscosity in all intestinal segments (r = − 0.76 to − 0.82; P < 0.001) and positively correlated with digesta dry matter in all intestinal segments (r = + 0.60 to + 0.67; P < 0.05), except for the proximal intestine (P = 0.18). Of the other minerals, potassium and magnesium absorption were positively correlated with digesta dry matter in the distal (r = + 0.56; P = 0.03) and proximal (r = + 0.54; P = 0.04) intestine, respectively. Phosphorus absorption was significantly negatively correlated with dry matter in the stomach (r = − 0.55; P = 0.03), middle (r = − 0.58; P = 0.02) and distal (r = − 0.54; P = 0.04) intestine. In conclusion, viscous cereal grains induce increases in digesta viscosity and decreases in digesta dry matter in Nile tilapia. These changes do not explain differences in nutrient digestibility among diets, but seem more related to differences in mineral absorption. The strong negative correlations between digesta viscosity and sodium absorption suggest negative effects of dietary viscous grains on intestinal water balance.     

等价电子组态原子光谱项推求方法

以同科电子f2组态光谱项推求为例,提出了用自旋因式化方法推求同科电子j-j耦合光谱项的一般方法。该法较为简单、适用,易于推广,可求出较复杂电子组态的原子光谱项。     

几种常用建材的等温吸放湿线试验研究

设计建造了恒温恒湿试验台，用盐水饱和溶液保持小室恒定的湿度，通过对３种常用建材的平衡湿容量研究，试验得到其等温吸放湿曲线，为围护结构动态湿特性研究提供了基本数据。     

Atomic Force Microscopy of A-Gliadin Fibrils and in situ Degradation

Atomic force microscopy (AFM) has been used in air and in aqueous buffer to study the structure of fibrils formed by the self-assembly of A-gliadin protein molecules. The images showed fibrils with a diameter of between 15 and 30 nm and lengths ranging from about 100 nm to 2 μm. No branched fibrils were observed, and there was no indication of a strong lateral inter-fibril interaction that would result in side-by-side association. Disassembly of the fibrils occurred when the pH of the aqueous buffer was reduced. In contrast the reverse process of fibril assembly and adsorption to the mica surface was less readily observed in situ. Some short fibrils were observed to assemble, but the lengths and densities were considerably less than those obtained by external deposition and drying.     

光谱水平电极撒样法同时测定 化探样品中银、锡、钼、铋四元素的研究

本文采用碘化钾＋ 光谱基物＋ 石墨粉为缓冲剂，以背景为内标，一次摄谱同时测定化探样品中的 Ａｇ 、 Ｓｎ 、 Ｍｏ 、 Ｂｉ４ 元素，绝对检出限（ｕｇ／ｇ） 分别为０ ．０２１ 、０ ．７９ 、０ ．１７ 、０ ．２０ 。测定范围（ｕｇ／ｇ） ： Ａｇ 为０ ．０２ ～２０ ； Ｓｎ 为０ ．８ ～５００ ； Ｍｏ 为０ ．２ ～２００ ； Ｂｉ 为０ ．２ ～２００ ，均能满足化探试样中微痕量元素测定的要求。本法在１ ｍ 光栅摄谱仪上摄谱，具有广泛的适用性，并且简便、快速、灵敏度高，成本低。     

基体辅助的激光解吸附质谱法测定猪促卵泡激素(pFSH)分子量

以单克隆抗休新和层析和逆向高效液相色谱技术取高纯猪促卵泡激素样品。采用基体辅助的激光解吸附质 技术对样品进行了检测，测得ｐＦＳＨ的分子量平均值为２４６２３ｄａｌｔｏｎｓ，其中α亚单位的分子量平均值１０９６３ｄａｌｔｏｎ；β亚单位的分子量平均值为１３６５９ｄａｔｌｔｏｎｓ。     

青椒对外源糖的吸收与分配规律研究

用含有14 C标记的外源糖 (葡萄糖和蔗糖 )点滴青椒叶片 ,示踪试验表明 :外源糖被叶片吸收后可运转到植株的各个部位 ,但集中向果实 ,幼嫩的茎、叶等生长比较旺盛的库性器官分配 ,其分配量与器官干重无关 ;青椒对外源葡萄糖的吸收率高于蔗糖     

磷对旱地胡麻氮吸收转运及利用的影响

为研究磷对旱地胡麻氮吸收转运及利用的影响,以胡麻品种‘轮选2号’和‘定亚22号’为材料,4个施磷(P₂O₅)水平(0、45、90、135 kg/hm²)为因素,采用完全随机区组设计,于2017年和2018年在定西进行大田试验。结果表明：磷影响旱地胡麻地上部分氮吸收转运和氮生理利用率,且年份间差异显著;年份、品种和磷互作对花期和成熟期地上部分氮吸收量、成熟期籽粒氮吸收量和分配率,茎叶和其他部分中氮总转运量、转运率、贡献率及氮生理利用率影响显著。与不施磷相比,施磷使旱地胡麻花期和成熟期地上部分氮吸收量平均提高76%和82%;成熟期籽粒中氮吸收量和分配率平均提高127%和25%;茎、叶和其他部分中氮的转运量和转运率分别平均提高556%、102%、237%和16%。‘轮选2号’氮生理利用率随施磷量增加而显著增加,‘定亚22号’氮生理利用率在施磷(P₂O₅)90 kg/hm²和135 kg/hm²间差异不显著。相关分析表明,施磷量与旱地胡麻氮吸收转运和利用显著正相关。