Effect of Alkali Stress on Soluble Sugar, Antioxidant Enzymes and Yield of Oat

Alkali stress can cause severe crop damage and reduce production. However, physiological processes involved in alkali stress in oat seedlings are not well understood. In this study, physiological responses and yield of oat to alkali stress were studied using the alkali-tolerant oat genotype Vao-9 and the alkali-sensitive oat genotype Baiyan 5. The results were: (i) low concentrations of alkali stress (25 and 50 mmol L-1) significantly reduced the yield and grain weight while increased the oat grain number per spike. A negative correlation between yield and malondialdehyde (MDA) content at the jointing and grain filling stages and positive correlations between yield on one hand and superoxide dismutase (SOD), and peroxidase (POD) activities on the other at the jointing stage were observed. There was a positive correlation between MDA and soluble sugar at the grain filling stage; (ii) soluble sugar content was increased at the jointing and grain filling stages and decreased at the heading stage by alkali stress; (iii) alkali stress increased the SOD activity during the heading and grain filling stages, and increased the POD activity at the heading stage. As compared to the control, the increase of MDA contents in alkali-treated oat was observed, during the jointing, heading and grain filling stages; (iv) under alkali stress, the oat genotype Vao-9 showed higher antioxidant enzyme activity and lower soluble sugar contents during the heading stage, and lower MDA contents than those in the oat genotype Baiyan 5 under alkali stress. The result suggested that the high ROS scavenging capacity and soluble sugar levels might play roles in oat response to alkali stress.     

大果沙棘全光照喷雾嫩枝扦插育苗试验

在全光照自动喷雾条件下,对大果沙棘嫩枝插条采用IBA、NAA、ABT-l号、ABT-2号4种植物生长调节剂,各3种浓度梯度的浸泡处理2 h,可明显促进插条生根。在供试的13种处理中,IBA 100 m g.L-1处理效果最好,生根率可达到98.8%。     

黄土沟壑区旱地仁用杏品种不同花型的数量分布及遗传分析

对黄土沟壑区旱地条件下"龙王帽"、"白玉扁"的不同花型数量分布及遗传力进行了分析,结果表明:"龙王帽"的有效花比例高达91.8,具有较大的丰产潜力,宜作为旱地主栽品种;"白玉扁"有效花比例仅为41.2,雌蕊败育率较高,丰产潜力小,仅宜作为授粉品种;花型主要受遗传因素控制(遗传力高达0.99),环境影响较小.     

蛋氨酸螯合锌不同添加量对肉用仔鸡生产性能的影响

将600只鸡分成3组，每组200只鸡。分别为对照组、试验1组和试验2组。对照组微量元素采用的饲料级无机盐；试验1组和试验2组分别添加60mg/kg，40mg/kg的羟基蛋氨酸螯合锌，以研究蛋氨酸螯合锌不同添加量对肉用仔鸡生产性能影响。试验结果表明，以微量元素氨基酸螯合物代替无机盐可显著提高内用仔鸡的生长速度和饲料转化率，提高养殖的经济效益,且肉用仟鸡日粮中蛋氨酸螯舍锌添加量以每千克饲料中添加60mg的效果最好。     

米易县核桃产业发展的思考

在论述了米易县核桃产业发展现状的基础上,分析了米易县发展核桃产业的必要性和存在的问题,针时存在问题提出了相应的对策和建议：一是以核桃基地建设为重点,合理规划核桃种植;二是以科技为依托,强化技术支撑体系;三是引进龙头企业,带动核桃产、工、销一体化发展;四是拓宽核桃产业发展的融资渠道;五是建立苗圃基地,确保良种供应;六是制定一系列的优惠政策,促进核桃产业健康快速发展。     

Aspects of the biology,ecology and seasonal fluctuations in biochemical composition of Donax Serra in the East Cape

Donax serra ROding (Pelecypoda) isalargesand mussel which forms vast populations on some East Cape shores. It is most abundant on exposed beaches where the sand is not too coarse and phytoplankton production is high. Adultsoccupy ¹ zonejust above the mean level of spring tide. Spat settle subtidally and move upshore as they grow. Growth is initially rapid, to about 32 mmatoneyearand48 mmattwoyears. Thereafter growth is very slow and most adult productions goesinto reproduction, with a small summerspawning and a large winterspawning each year. Somatic production is low, as large adults totally dominate the population and have low growth and low mortality. Reproductive production is relatively high and P/B values of 0,2 and 0,5 are suggested for growth and reproduction. D. serra was found to be very tolerant of fluctuating salinitiesforupto four days and should be able to penetrate river mouths, but is limited by restricted swash action. Total dry-tissue mass, energy and biochemical constituents showed some seasonal fluctuations related mainly to the reproductive cycle. Carbohydrate appears to be a moreimportant energy reserve than lipids.     

Studies on the Littoral Seaweed Epifauna of St Croix Island 2. Composition and Summer Standing Stock

The fauna associated with the littoral seaweeds of St Croix Island has been investigated in terms of numbers and biomass (grams and kilojoules). The seaweeds support an abundant and diverse epifauna dominated by crustaceans, nematodes, annelids, molluscs and mites. The summer standing stock of epifauna from the seaweeds occurring in three different metre wide vertical strips of shore was determined and found to tota 2,1— 4,6 x 10⁶ individuals (equivalent to 85—117 g dry mass or 1,2— 1,7 x 10³ kJ). The nature of the seaweed microenvironment influences the epifauna and algal turfs and tufted seaweeds supported more epifauna than seaweeds with flattened thalli. A model depicting feeding relationships and the role of seaweed epifauna in the littoral zone is given and suggests that epifauna feed on detritus, plankton, algae or other epifauna and are in turn preyed upon, selectively or non selectively, by littoral macrofauna and transient predators.     

The nucleocapsid of hepatitis B virus is both a T-cell-independent and a T-cell-dependent antigen

One characteristic of the immune response during hepatitis B virus (HBV) infection in humans is the vigorous production and subsequent persistence of antibodies of immunoglobulin (Ig) classes M and G to the nucleocapsid antigen (HBcAg). In this study HBcAg was shown to be similarly immunogenic in mice. When injected into athymic (nude) B10.BR and athymic BALB/c mice, HBcAg induced IgM and IgG class antibodies to HBc in spite of the absence of T cells in nude mice. In euthymic mice, HBcAg efficiently stimulated T-cell proliferation in vitro and helper T-cell function in vivo. The dual functions of HBcAg as a T-cell-independent and a T-cell-dependent antigen may explain its enhanced immunogenicity. Denaturation of HBcAg yields a nonparticulate antigen designated HBeAg; when HBeAg was used as the immunogen, antibody production required helper T-cell function. Although HBcAg and HBeAg are serologically distinct, they are structurally related, and in these experiments were highly cross-reactive at the T-cell level. These results suggest that the elevated levels of IgM antibodies to HBc and the enhanced immunogenicity of HBcAg during HBV infection in humans reflect the ability of HBcAg to directly activate B cells to produce antibodies to HBc in the presence or absence of HBcAg- or HBeAg-sensitized T cells.     

Evaluation of Cluster Bean Meal Cyamposis fefrugonoloba as a Dietary Protein Source for Common Carp Cyprinus carpio L.

Abstract— A12-wk feeding experiment was conducted to study the feasibility of utilizing cluster bean seed meal (CBM) as a replacement for fishmeal in the diets for common carp Cyprnus carpio fingerlings. The replacement levels of cluster bean meal protein in the diets were 25, 50, 75, and 100% of the total fishmeal protein. All diets were isonitrogenous at 33.1% crude protein and isocaloric at 4.8 Kcal/g. There were significant differences in the final individual weights, weight gains, specific growth rates (SGR %/d), feed conversion ratios (FCR), feed efficiency ratio (FER), protein efficiency ratios (PER), and feed intake among fish group ( P × 0.05). Common carp fed the diet containing 50% (CBM) exhibited comparable growth to those fed a fishmeal-based diet. Digestibility of protein, energy and lipid decreased with increasing levels of CBM above 50% of total fishmeal replacement in the diet. Incorporation of CBM in diets significantly affected the dry matter, protein, and energy of whole fish body. These results suggest that CBM can replace 50% of the fishmeal in diet for common carp.