Towards soil management with Zn and Mn: estimates of fertilisation efficacy of Citrus trees

Nutrient management recommendations for fruit crops lack the understanding of the efficiency of soil fertilisation with manganese (Mn) and zinc (Zn), which could substitute, in part, the traditional foliar applications. Fruit yield of trees in response to Zn and Mn supply via soil may be limited either by sorption reactions with soil colloids or low solubility of fertilisers. We investigated the effects of fertiliser sources and rates of Mn and Zn applied to soils with different sorption capacities on nutrient uptake, biochemical responses and biomass of Citrus. Two experiments were carried out with 2‐year‐old sweet orange trees that received applications of Mn or Zn. The first experiment evaluated the application of Mn fertilisers (MnCO₃ and MnSO₄) at three levels of the nutrient (0, 0.7 and 3.5 g plant^?1 of Mn) in two types of soil (18.1% and 64.4% of clay, referred to as sandy loam and clay soils, respectively). The second experiment, likewise, evaluated Zn fertilisers (ZnO and ZnSO₄) and nutrient levels (0, 1.0 and 5.0 g plant^?1 of Zn). Application of Mn and Zn increased nutrient availability in the soils as well as leaf nutrient concentrations in the trees. The lowest rates, 0.7 g plant^?1 of Mn and 1.0 g plant^?1 of Zn, both as sulphate, were sufficient to supply these micronutrients to sufficient levels in leaves, flowers and fruits. Metal toxicity to plants occurred with higher doses of both nutrients and to a large extent in the sandy soil. In this case, protein bands lower than 25 kDa were observed as well a decrease on leaf chlorophyll content. In the clay soil, despite increased micronutrient concentrations in the plant, responses were less pronounced because of higher adsorption of metals in the soil. Superoxide dismutase (SOD, EC 1.15.1.1) isoenzyme activity was determined by non‐denaturing polyacrylamide gel electrophoresis (PAGE). The Cu/Zn‐SOD isoenzymes increased with increased Zn rates, but in contrast, when Mn was applied at the highest rate, the activity of Cu/Zn‐SODs decreased. The SOD activity pattern observed indicated increased production of superoxide and consequently an oxidative stress condition at the highest rates of Zn and Mn applied. The results demonstrated that the soil application of Mn and Zn can supply nutrient demands of orange trees, however the low solubility of fertilisers and the high sorption capacity of soils limit fertilisation efficiency. On the contrary, application of sulphate source in sandy soils may cause excess uptake of Mn and Zn and oxidative stress, which impairs the photosynthetic apparatus and consequently tree growth.     

Efficacy of Fluensulfone in a Tomato–Cucumber Double Cropping System

Vegetable crops in the southeastern United States are commonly grown on plastic mulch with two crop cycles produced on a single mulch application. Field trials were conducted in 2013 and 2014 in two locations to evaluate the efficacy of fluensulfone for controlling Meloidogyne spp. when applied through drip irrigation to cucumber in a tomato–cucumber double-cropping system. In the spring tomato crop, 1,3-dichloropropene (1,3-D), fluensulfone, and a resistant cultivar significantly decreased root galling by 91%, 73%, and 97%, respectively, compared to the untreated control. Tomato plots from the spring were divided into split plots for the fall where the main plots were the spring treatment and the subplots were cucumber either treated with fluensulfone (3.0 kg a.i./ha. via drip irrigation) or left untreated. The fall application of fluensulfone improved cucumber vigor and reduced gall ratings compared to untreated subplots. Fluensulfone reduced damage from root-knot nematodes when applied to the first crop as well as provided additional protection to the second crop when it was applied through a drip system.     

荒漠甲虫小胸鳖甲抗冻蛋白的酵母表达及应用

昆虫抗冻蛋白(Antifreeze protein,AFP)的抗冻活性很高,可应用于生物组织和细胞的低温保存。为了在酵母中表达荒漠甲虫小胸鳖甲Microdera punctipennis抗冻蛋白Mp AFP698,并确定其在低温下的保护作用,本文通过构建真核表达载体p PIC9K-Mpafp698,转化巴斯德毕赤酵母GS115,诱导表达小胸鳖甲抗冻蛋白Mp AFP698。利用免疫印迹(Western blotting)分析Mp AFP698蛋白的特异性表达,结果显示Mpafp698基因可整合到酵母基因组中并分泌表达,且酵母自身蛋白很少分泌表达。检测抗冻蛋白的低温保护作用,结果发现,小胸鳖甲抗冻蛋白可显著改善冷冻小鼠肝脏等器官的细胞形态,降低血细胞在4℃的溶血率,提高SF9细胞冻融后的存活率。本研究表明,小胸鳖甲AFP可以在毕赤酵母中分泌表达,便于纯化,有良好的低温保护效果。     

单抗药物专题报告——走过孕育期，收获正当时（Ⅰ）

单抗药物以靶向性强、特异性高、副反应小等优势在癌症、自身免疫性疾病等治疗领域取得了快速发展,成为医药行业增速最快的 细分领域。报告采用文献调研、数据库检索、数据统计与分析等定性定量研究方法,从竞争优势、应用领域、给药剂型、产业现状、成长 路径等角度对国内外单抗药物领域进行多角度、多层次的分析,旨在为相关医药企业明确发展方向、确定产品研发思路及制定市场策略提 供参考。     

Tree mineral nutrition is deteriorating in Europe

The response of forest ecosystems to increased atmospheric CO₂ is constrained by nutrient availability. It is thus crucial to account for nutrient limitation when studying the forest response to climate change. The objectives of this study were to describe the nutritional status of the main European tree species, to identify growth‐limiting nutrients and to assess changes in tree nutrition during the past two decades. We analysed the foliar nutrition data collected during 1992–2009 on the intensive forest monitoring plots of the ICP Forests programme. Of the 22 significant temporal trends that were observed in foliar nutrient concentrations, 20 were decreasing and two were increasing. Some of these trends were alarming, among which the foliar P concentration in F. sylvatica, Q. Petraea and P. sylvestris that significantly deteriorated during 1992–2009. In Q. Petraea and P. sylvestris, the decrease in foliar P concentration was more pronounced on plots with low foliar P status, meaning that trees with latent P deficiency could become deficient in the near future. Increased tree productivity, possibly resulting from high N deposition and from the global increase in atmospheric CO₂, has led to higher nutrient demand by trees. As the soil nutrient supply was not always sufficient to meet the demands of faster growing trees, this could partly explain the deterioration of tree mineral nutrition. The results suggest that when evaluating forest carbon storage capacity and when planning to reduce CO₂ emissions by increasing use of wood biomass for bioenergy, it is crucial that nutrient limitations for forest growth are considered.     

RNA干扰在疾病治疗上的应用

RNA干扰(RNA interference,RNAi)是一种双链RNA分子在mRNA水平上引发的特异性基因沉默现象。RNAi在基因治疗方面表现出了光明的前景,已成功地应用于多种疾病的临床治疗。本文主要介绍了RNAi在疾病治疗上的应用及研究进展。     

大气CO2浓度倍增和施氮对冬小麦光合及叶绿素荧光特性的影响

采用开顶式气室,通过土培盆栽实验研究了不同大气CO2浓度(背景空气浓度375μmol·mol-1和倍增浓度750μmol·mol-1)和氮素水平(不施氮和施氮0.25 g/kg)下两个冬小麦品种(小偃6号和小偃22)主要生育期(拔节、孕穗、扬花、灌浆期)叶片叶绿素含量和荧光动力学参数的变化.结果显示,与背景CO2浓度相比,在不施氮条件下大气CO2浓度倍增处理的小麦叶片出现明显的光合下调现象,而施氮时变化不明显;同时,CO2浓度倍增后小麦各主要生育期叶片叶绿素含量均有不同程度地下降,荧光参数初始荧光(F0)值明显提高,最大荧光(Fm)、可变荧光(Fv)、最大光能转换效率(Fv/Fm)和PSⅡ潜在活性(Fv/F0)值均显著降低.施氮可提高冬小麦各个时期叶片叶绿素含量、Fm、Fv、和Fv/F0值,降低F0值;不施氮条件下,大气CO2浓度倍增对冬小麦各主要生育时期叶绿素含量和荧光参数的影响明显,而施氮后影响微弱.研究表明,大气CO2浓度升高对冬小麦光合速率、叶绿素含量和光系统Ⅱ(PSⅡ)的光合电子传递和潜在活性具有一定抑制作用,通过施氮可以有效地缓解其负面效应.     

急性心肌梗死静脉溶栓治疗和心电监护的体会

目的探讨静脉溶栓治疗和心电监护对急性心肌梗死（AMI）的疗效。方法全部病例均符合WHO规定的AMI诊断标准,治疗均给予尿激酶（UK）100U～150万U,加生理盐水100ml,静脉点滴,30min滴完。同时给予心电监护,以期能及时发现患者存在的各种心律失常。结果本组72例中,均无牙齿出血、消化道出血及出血性脑卒中等并发症的发生,1例出现静脉穿刺部位皮肤瘀斑;所有患者均好转出院。结论静脉溶栓治疗和心电监护对急性心肌梗死（AMI）的疗效可靠,值得在基层医院使用。     

酵母脂肪酶的制备及应用新进展

脂肪酶是工业领域应用非常广泛的一类绿色生物催化剂,由于脂肪酶可催化酯水解、酯化、转酯化、醇解和氨解等多种反应,在食品加工,有机合成,制备生物柴油等方面均得到了较为广泛的应用,是目前的研究热点.微生物是脂肪酶的重要来源之一,其中酵母脂肪酶被认为是非常安全的一类脂肪酶,也是应用最为广泛的一类脂肪酶.该文介绍了酵母脂肪酶的制备和应用研究概况,重点综述了其在多个应用领域中的最新研究进展.挖掘更多的新型高活性脂肪酶,降低脂肪酶的生产成本,提高酶的重复使用率是今后脂肪酶应用研究亟待解决的问题.     

Foliar Spraying and Seed Soaking of Zinc Fertilizers Decreased Cadmium Accumulation in Cucumbers Grown in Cd-Contaminated Soils

It is important to use proper agronomic management to reduce cadmium (Cd) accumulation in plants, ensuring food safety. To find the most effective agronomic approach, the effect of foliar spraying and seed soaking of zinc (Zn) fertilizers on Cd accumulation in cucumbers (Cucumis sativus L.) grown in two soil Cd levels (2 and 5 mg kg^?1 Cd) with and without an immobilizing amendment (red mud, RM) was investigated in the present study. The results showed that the treatment of foliar Zn or seed Zn significantly decreased the Cd concentration in cucumber shoots by about 12–36% in Cd-contaminated soils without amendment. Combined with RM treatment, the foliar Zn treatment further decreased the Cd concentration in cucumber shoots by up to 48–66% in Cd-contaminated soils. There were significant negative correlations between Cd and Zn concentrations in shoots of cucumbers grown in soils treated with RM and foliar Zn. The results revealed that the cucumber seedlings treated with RM and foliar Zn had a higher capacity for limiting the transfer of Cd to aboveground tissues. The results also suggested that increasing seed Zn concentrations sufficiently might act as an efficient, economic, and practical method for decreasing Cd uptake in crops grown in mildly Cd-contaminated and Zn-deficient soils.