土壤中有机碘的转化、挥发及其影响因素研究进展

土壤中有机碘的形成、转化及挥发对自然界中碘的迁移转化、生态安全、人体健康具有重要意义。本文基于前人对土壤中碘的相关研究,介绍了土壤中碘的形态和含量,重点对碘与有机质结合生成有机碘的反应机理、土壤中碘有机化的影响因素和土壤中有机碘的挥发进行了阐述。土壤中IO₃^–、I^–发生氧化还原反应,形成中间体物质HIO、I₂,中间体通过化学转化和生物转化两种途径生成有机碘。土壤pH、氧化还原电位、有机质含量、酶活性、Fe/Mn氧化物及其氢氧化物浓度影响有机碘的形成和转化。有机碘的挥发在微生物和高等植物中主要通过在体内生成挥发性甲基碘的过程实现。     

英国高等农业教育的启示——以哈珀亚当斯农学院为例

针对扩招后我国普通高等农业院校存在的普适性问题,介绍并分析了英国哈珀亚当斯农学院的办学宗旨,以及在办学理念、人才培养方案、教学方式、教学管理、质量监控等方面的特点,提出国内高等农业教育发展的5大对策：服务新农村建设,明确人才培养目标;改革传统教学模式,加强实践教学,重视能力培养;实行学分制与导师制,加强学生创新能力与个性化培养;理顺教学管理关系,建立质量监控评价体系;以学生为中心,完善支持服务体系,培养优良品格。     

Evidence of arrested silk growth in maize at high planting density using phenotypic and transcriptional analyses

Increasing the planting density is an effective way to increase the yield of maize(Zea mays L.), although it can also aggravate ovary apical abortion-induced bald tips of the ears, which might, in turn, reduce the yield. While the mechanism underlying the regulation of drought-related abortion in maize is well established,high planting density-related abortion in maize remains poorly understood. Therefore, the present study was designed to investigate the mechanism underlying the ovary apical ab...     

百合雌蕊中杂交亲和性与不亲和性差异表达基因分析

东方百合与卷瓣组野生百合杂交(简称OS组合)，属于亲缘关系最远的组间杂交，杂交障碍最大。挖掘雌蕊中杂交亲和性与不亲和性差异表达基因，有可能解释不亲和性杂交中引起花粉管定向生长异常的机理，进而阐明不亲和性杂交的分子机理，为实施克服杂交不亲和障碍技术措施提供依据。本研究采用抑制消减杂交技术(SSH技术)，分别以不亲和性杂交和亲和性杂交的东方百合雌蕊为试验组(tester)和驱动组(driver)，建立正向抑制消减杂交文库，随机挑选180个阳性克隆，经过测序、去劣、去冗余、序列比对，有113个EST与数据库中的已知序列具有同源性，最终获得10个差异表达基因。采用RT-PCR技术对10个差异表达基因进行验证，其中有1个基因在不亲和性杂交的雌蕊中表达上调、7个基因表达下调、2个基因无明显变化。对差异表达基因进行功能注释及分类，差异表达基因主要集中于信号转导(包括丝氨酸/苏氨酸蛋白磷酸酶PP2A-3、钙依赖蛋白激酶CDPK、小G结合蛋白)、抗逆防御(包括分子伴侣(clpB)、过氧化氢酶CAT2)、转运(包括质膜ATPase、焦磷酸酶质子泵)、蛋白命运(包括60S核糖体蛋白)等功能类别。据此推测，在东方百合×山丹组(系)间不亲合性杂交育种过程中，可能引起雌蕊与花粉管信号交流异常、物质转运能力减弱和雌蕊耐受逆境能力降低，从而导致杂交不亲和性。      

In situ emission of BVOCs by three urban woody species

Controlling and monitoring air quality in cities requires understanding anthropogenic sources, but also natural sources must be considered. This is because beneficial Biogenic Volatile Organic Compounds (BVOCs) can exacerbate air pollution by reacting with anthropogenic pollutants. Although these compounds help trees survive, they may have negative effect on human life in polluted cities. In this study we measured terpenoid emissions of urban trees early and late in the growing season, using Solid Phase Micro-extraction (SPME) in a branch enclosure system. Results showed that Robinia pseudoacacia and Platanus orientalis emitted significant amounts of isoprene throughout the season. Isoprene emission early in the season was roughly the same for both species. Late in the season, the standardized emission rate increased to 17.8 and 45 μg g⁻¹ dw h⁻¹ for R. pseudoacacia and P. orientalis, respectively. Furthermore, all trees emitted significant amounts of 2-ethylhexanol late in the season (7.3, 7.9, and 9.2 μg g⁻¹ dw h⁻¹ for Fraxinus rotundifolia, R. pseudoacacia, and P. orientalis, respectively). In conclusion, trees that are typically planted in urban Tehran, emit significant amounts of isoprene. Planting more F. rotundifolia and fewer P. orientalis trees would help improve air quality in Tehran and the cities like Tehran.     

Broccoli yield response to environmental factors in sustainable agriculture

A reduced rank factorial regression was carried out to assess effects of environmental factors in sustainable agriculture on yield performances of homogeneous (one F1 hybrid) and heterogeneous (one landrace, LR, and two derived synthetics) broccoli varieties under Organic Agriculture (OA) and Low-Input (LI) management systems. The study was motivated by a general lack of data on environmental variables that affect broccoli yield. Agronomic trials were carried out for three years in three locations in Central Italy with different pedo-climatic conditions. Reduced rank factorial regression was efficient in summarising the effect of environmental variables on the pattern of Genotype (G) × Environment (E) interactions.Nitrogen content, together with rainfall, minimum temperature and clay content, were the most important environmental variables and explained 91% of the variability in the G × E interaction matrix. A mild and nitrogen-rich environment allowed good performances to be achieved with all genotypes and maximised the F1 hybrid yield. The synthetic varieties and the LR tolerated a high clay content, even though broccoli crops prefer, in general, alluvial, deep and permeable soils without water stagnation. This suggests that the above mentioned varieties are the best materials for these yield-limiting environments, possibly because they were selected under those conditions.The results highlight the needs (i) to carry out further agronomy research aimed at identifying the most suitable areas and optimizing the control of environmental variables in OA and LI (in particular, type, quantity and time of application of N fertilization), (ii) to develop specific breeding programs for OA and LI and, while carrying them out, (iii) to evaluate the responses of the genotypes under selection to limiting environmental variables.     

Effect of nitrogen fertilization on Fusarium head blight in spring barley

Nitrogen fertilization has been shown to influence the occurrence and the impact of Fusarium head blight in wheat. It also plays a key role in adjusting barley quality to the requirements of the malting industry, implying specific contents of protein. The present study investigated the effect of nitrogen input on the incidence of relevant Fusarium species in spring barley under field and greenhouse conditions. Grain material from differently fertilized field plots was analyzed for fungal DNA and mycotoxins by qPCR and LC-MS/MS, respectively. Under natural pathogen pressure no effect of nitrogen on infection was observed. When pathogen pressure (Fusarium culmorum and Fusarium avenaceum) was increased via species-specific soil-surface inoculation, nitrogen application reduced contents of Fusarium DNA and mycotoxins in barley grain. Nitrogen-dependent canopy parameters were recorded over the season and correlated with DNA and mycotoxin data. Apparently, sparser canopy permitted more Fusarium infections in unfertilized plots. In addition, well nitrogen-fertilized plants allowed less fungal development in the barley spike after spray inoculation in the greenhouse. These results suggest that nitrogen fertilization restricts Fusarium grain infection of barley by influencing canopy characteristics and possibly plant physiology.     

家猫非繁殖季节诱导发情配种后排卵时间的确定

作者尝试在非繁殖季节应用外源促性腺激素对家猫进行人工诱导发情,并判断其较为准确的排卵时间。试验采用PMSG两次注射法对雌性家猫进行诱导发情,注射总剂量为150 IU,PMSG处理后的第6 d肌肉注射hCG（100 IU/只）并合笼配种。分别于合笼后的24、30、36 h手术法摘除家猫卵巢及输卵管部,观察记录卵巢排卵情况并对排卵侧的输卵管进行冲胚。试验结果显示,利用外源性促性腺激素可使家猫在非繁殖季节发情,且排卵时间范围为合笼配种后30 h左右。     

Establishment of Fetal Large-tailed Han Sheep Fibroblasts Cell Line Transfected with Lipofectamine 2000 Vector Containing TLR4 Gene

Exploiting the method of liposome transfection to obtain modified Toll-like receptors 4(TLR4) gene fibroblast cells as competent donor, build reconstructed embryos, which finally produced transfected TLR4 gene and gender controllable Large-tailed Han sheep by somatic cell nuclear transfer technology.In this study, through primary culturing the fetus dermal fibroblasts from Large-tailed Han sheep, to identify the SRY gene gender.Using the method of liposome transfection transferred TLR4 gene into fibroblast cells, then detected whether TLR4 gene expression stably or not in morphology level and molecular level respectively, transplanting fibroblast cells which stably expressed TLR4 gene into oocytes without nucleus from Large-tailed Han sheep for building reconstructed embryos.To harvest 5 positive clones by fibroblast cells with stable expression level of TLR4.According to the identification of the SRY gene gender, the cell lines were female.The analysis of Real-time fluorescent quantitative PCR, the fourth generation of transfected cells had the highest expression level of TLR4, which were higher than control group in 7.4816 times (P<0.01).The cleavage reconstructed embryos had stable expression level of EGFP.We succeeded in building reconstructed embryos with TLR4 gene and lay the foundation for producing the disease-resistant and gender controllable transgenic sheep in the future.