不同采后处理对草莓品质和腐烂的影响

宝交早生草莓在0℃下自然降氧贮藏10 d,好果率84%,商品率达98%。用10%CO_2处理可将草莓在0℃的贮藏时间延长到20 d,好果率和商品率均为94%,CO_2浓度超过20%会使草莓产生酒精味。SO_2慢性释放剂处理也有较好的防腐效果。     

含硫天然气集输管网的腐蚀控制

含硫天然气腐蚀性较强,天然气集输管网的耐硫腐蚀不容忽视。介绍了含硫天然气集输管网的腐蚀机理,指出水的存在是含硫天然气具有腐蚀性的前提条件。梳理了从管网设计到运行维护各个环节的防腐工作,指出设计阶段的防腐工作渗透于管网选材、管网敷设、缓蚀剂加药装置、清管装置、腐蚀监测装置、管网附属装置等各个环节的设计中;而运行阶段的防腐措施,主要有添加缓蚀剂和设置阴极保护两种,腐蚀检测则是动态了解管道腐蚀状况和科学制定维修计划的有效手段。     

比色法快速测定党参中二氧化硫的残留量

[目的]测定党参中二氧化硫的残留量。[方法]采用比色法快速测定党参中二氧化硫的残留量。[结果]在0.0～48.0μg/ml范围内,二氧化硫浓度与吸光度的线性关系良好,相关系数R为0.999 2,相对标准偏差在0.54%～1.66%;加标回收率为90.1%～103.7%,RSD为1.16%～5.17%(n=6),且具有良好的重现性和稳定性。应用测试结果表明,比色法的测定结果与酸蒸馏法相似。[结论]该方法简便、快速、灵敏度高、干扰少,可用于党参中二氧化硫的残留量测定。     

小鼠Foxc2质粒载体的构建及功能鉴定

构建pcDNA3.1-Foxc2真核表达载体,并以脂质体转染3T3-L1前体脂肪细胞,探究Foxc2对脂代谢的影响。取孕后15d小鼠腹部脂肪组织提取总RNA,用PCR扩增Foxc2全长序列并连接至pMD18-T载体,测序正确后克隆至pcDNA3.1(+)真核表达载体,成功构建pcDNA3.1-Foxc2重组质粒载体。重组质粒转染3T3-L1前体脂肪细胞系,以未转染和空载体转染作为对照,通过RT-PCR和Western blotting法检测Foxc2核酸及蛋白表达,同时检测3T3-L1前体脂肪细胞中脂代谢相关基因FAS、ATGL、HSL及PPARγ的表达。结果显示,重组质粒转染组细胞中Foxc2的核酸和蛋白水平均显著高于对照组。同时发现超表达Foxc2显著降低FAS表达,显著升高HSL及PPARγ的表达,但是对ATGL的表达无显著影响,表明Foxc2具有抑制脂肪沉积的功能。     

嗜盐紫色硫细菌283-1的耐盐机制

菌株283-1是一株中度嗜盐紫色硫细菌,对其耐盐特性和机理进行了初步研究。结果表明,菌株283-1在改良的Pfennig紫色硫细菌培养基中最大能耐受2.3mol·L-1 NaCl,其生长对Na+有专一依赖性,对Cl-依赖性较弱;它主要通过在胞内积累相容性溶质甜菜碱来对抗胞外渗透压力,胞内甜菜碱的含量随培养基中NaCl浓度增加而增加,2.0mol·L-1 NaCl时浓度可达到156.4mg·g-1干重。外源添加甜菜碱可以明显提高该菌株耐盐生长的能力。     

Research Advances in Effect of Nitrogen Deposition on Forest Carbon Sequestration

Nitrogen deposition imposes important impact on the function and the stability of forest carbon sequestration.This paper reviewed the research advances in the increasing response of forest carbon sequestration to nitiogen deposition, described the application prospects of stable carbon isotope technique in the research field.And finally this paper pointed out that,on the condition that nitrogen deposition rises,on the allocation of forest photosynthetic products and the change in soil carbon turnover rate are the two hotspots in the future carbon cycling research.     

家禽脂肪酸代谢及其在禽蛋中的沉积和营养调控

在肝脏中载脂蛋白作用下,内源合成或外源获取的脂肪酸以甘油三酯的形式同胆固醇及其他脂类组装形成极低密度脂蛋白(VLDL)。VLDL经血液循环到达卵巢,穿过卵母细胞外层屏障后,经卵母细胞受体介导的内吞作用进入卵母细胞发生沉积。而机体的营养状况或饲粮中营养成分的改变可通过影响脂肪酸的从头合成或VLDL结构直接或间接影响禽蛋中脂肪酸的最终沉积。本文阐述了家禽体内脂肪酸的来源、转运与沉积过程,并探讨了脂肪酸代谢及其在禽蛋中沉积的营养调控。     

林分类型和氮添加对亚热带森林土壤氧化亚氮排放的影响

为揭示亚热带森林土壤N₂O排放对林分类型和氮添加的响应特征,选取位于福建省三明市的中亚热带米槠次生林、杉木人工林和马尾松人工林土壤为研究对象,分别设置无氮添加(N0 mg/kg)、低氮添加(N10 mg/kg)、中氮添加(N25 mg/kg)和高氮添加(N50 mg/kg)4个氮添加水平,进行微宇宙培养试验,测定土壤N₂O排放。结果表明：与无氮添加处理相比,氮添加整体上降低3种林分土壤pH,增加土壤NH₄⁺-N和NO₃^--N含量。无氮添加处理中杉木人工林和马尾松人工林土壤N₂O累积排放量分别为9.67和9.62 mg/kg,显著高于米槠次生林土壤N₂O累积排放量6.81 mg/kg。低氮添加处理中杉木人工林和马尾松人工林土壤N₂O累积排放量显著高于米槠次生林。但在中氮和高氮添加处理中,3种林分土壤N₂O累积排放量均无显著性差异。不同氮添加处理均促进3种林分土壤N     

A Screening Trial of 28 Species Conducted on Non-Saline and Saline Soils in Dry Tropical Northeast Australia

Abstract

A trial to examine the suitabilities of 28 tree species for both non-saline and saline soils was carried out in a dry tropical area of northern Australia. The trial consisted of two experiments, Experiment 1 on a non-saline site and Experiment 2 on a saline site. In each experiment, trees of all the species were grown in a randomised complete block design with 6 blocks (replicates) and were measured for survival; height and diameter at breast height (DBH) at age 24 months. These parameters were found to differ significantly between species in both experiments. Of all species tested, Azadi-rachta indica, Eucalyptus camaldulensis, E. citriodora, E. maculata, E. pellita, E. raveretiana, Khaya senegalensisand Paulowniafortue-niihad high survival and fast growth in height and DBH on the non-saline site while E. camaldulensis, E. drepanophylla, E. moluc-cartaand E. raveretianaperformed better on the saline site. Salinity greatly affected survival for some species and reduced tree growth in both height and DBH for most species tested. E. camaldulensisis suggested to be one of themost important species for land rehabilitationin theregion.