石灰性土壤交换性钙和镁测定方法的研究

石灰性土壤交换性盐基组成的测定,通行的方法是采用70%乙醇溶液反复洗盐,再经pH 8.50.1 mol L-1氯化铵-70%乙醇(CH3CH2OH)溶液进行多次交换处理,测定交换液中的K+、Na+、Ca2+、Mg2+浓度。但此方法常常受操作步骤繁琐,以及土壤中碳酸盐的溶解量因多次浸提而增加的困扰,最终导致测定结果偏高。基于上述原因,选择不同浓度、不同pH的NH4OAc和NH4Cl 10种交换剂,对比分析10种交换剂中的碳酸盐溶解度和土壤交换性钙镁含量。结果表明,pH=8.5 1 mol L-1氯化铵-70%乙醇(CH3CH2OH)溶液较适合石灰性土壤交换性盐基的测定。此新方法是先经70%乙醇(CH3CH2OH)溶液洗盐,再用pH8.5 1 mol L-1氯化铵(NH4Cl)-70%乙醇(CH3CH2OH)溶液进行一次性交换处理,然后测定交换液的K+、Na+、Ca2+、Mg2+浓度,简化了操作程序的同时有效抑制了土壤碳酸盐的溶解,降低了测定结果的偏差。     

天津设施农业机械化生产现状调研

大力发展设施农业是天津市产业融合发展的重点。对天津市设施农业生产情况,采用入户调查和电话询问相结合的方式开展了调研。分析了天津市设施农业机械化水平、设施标准化建设水平、管理信息化水平、人员职业化水平等影响设施农业发展的指标因素,指出设施农业发展中存在的问题和产生原因,并提出了针对性建议,对促进天津市都市现代农业健康发展具有十分重要的意义。      

大孔吸附树脂纯化生姜提取物中6-姜酚工艺优化

比较了6种大孔吸附树脂对6-姜酚的吸附和解吸性能,在静态吸附研究基础上筛选出效果较好的树脂进行动态试验,并通过HPLC-UV和GC-MS对纯化前、后的成分进行了定性和定量分析。结果表明:D101型大孔树脂更适合纯化姜油树脂中的6-姜酚,其纯化的最佳工艺条件为:上样液质量浓度2 mg/mL,流速2 mL/min,3 BV去离子水洗脱,然后用体积分数80%乙醇以2 mL/min的流速洗脱4 BV,可以使6-姜酚的纯度从1.54%提高到71.32%。     

不同土壤水分条件下尿素类型对夏玉米营养品质的影响

为了进一步探讨夏玉米品质性状的水氮调控效应,以郑单958为供试材料,于2012—2013年2个生长季在山东省微山县农业局实验站防雨棚中进行了池栽试验。研究了不同土壤水分条件下普通尿素和包膜复合肥对夏玉米籽粒品质性状的影响。试验结果表明,同一土壤水分条件下,包膜复合肥处理的夏玉米籽粒蛋白质含量和产量、粗脂肪含量和淀粉含量均显著高于不施氮处理和普通尿素处理（基施+小喇叭口期追施）。同一氮肥处理,维持土壤田间最大持水量75％时,夏玉米籽粒蛋白质产量、粗脂肪含量和淀粉含量均显著高于维持土壤田间最大持水量50％;而籽粒蛋白质含量却显著降低,但包膜复合肥处理仍高于普通尿素处理。因此,与普通尿素相比,不论在干旱或土壤水分适宜时,包膜复合肥均能明显提高籽粒蛋白质含量、粗脂肪含量和淀粉含量,改善夏玉米籽粒的营养品质。      

山茱萸种子休眠的破除与试管萌发

本文研究了山茱萸种子的吸水性,并用切端露胚法、浓硫酸处理、不同激素种类及浓度处理和低温层积两个半月后分别在培养皿中、土壤中、盛有湿沙的营养钵中及试管中进行种子萌发的试验,结果表明山茱萸种子休眠的原因除种皮限制;胚未完成后熟或胚未完全发育;种皮中有抑制物质外还有土壤基质透气性差及其机械阻力的因素.     

Rapid evolution of Ophraella communa cold tolerance in new low-temperature environments

Low winter temperatures severely stress newly arriving insect species. Adaptive evolutionary changes in cold tolerance can facilitate their establishment in new environments. Ambrosia artemisiifolia, a noxious invasive plant, occurs throughout China. Ophraella communa, a biological control agent of A. artemisiifolia, mainly occurs in southern China. However, in 2012, it established populations in Beijing (39.98°N, 115.97°E) following introduction from Laibin (23.62°N, 109.37°E), implying cold adaptation. The mechanisms underlying its rapid evolution of cold tolerance remain unknown. We investigated the levels of cryoprotectants and energy reserves in adult O. communa from two latitudes. In high-latitude insects, we found high trehalose, proline, glycerol, total sugar, and lipid levels; five potential genes (Tret1a, Tret1b, Tret1-2, P5CS, and GST), responsible for regulating cold tolerance and involved in trehalose transport, proline biosynthesis, and glutathione S-transferase activation, were highly expressed. These hybridisation changes could facilitate cold temperature adaptation. We demonstrate the genetic basis underlying rapid adaptation of cold tolerance in O. communa, explaining its extension to higher latitudes. Thus, specialist herbivores can follow host plants by adapting to new temperature environments via rapid genetic evolution.

     

The expression of genes related to adipocyte differentiation in pigs

The purpose of this study was to detect differential expression of genes related to adipocyte differentiation in pigs by suppression subtractive hybridization. Adipocytes and stromal vascular cells (a fraction containing preadipocytes) from pig adipose tissue were isolated for mRNA extraction. The cDNA from preadipocytes was subtracted from the cDNA from adipocytes. The subtracted gene fragments were cloned into pGEM-T Easy TA cloning vector. We selected 384 clones for gene sequence determination and for further analysis. These genes were subjected to a differential screening procedure to confirm the differential expression of genes between the 2 cell types. We found that at least 36 genes were highly expressed in the adipocytes compared with preadipocytes. Among these, 6 genes including 2 novel genes with the greatest differences were selected and confirmed by Northern analysis. We found that angiotensin I-converting enzyme (ACE), ataxia-telangiectasia mutated protein (ATM), calpain 1, and stearoyl coenzyme A desaturase 1 (SCD1) were highly expressed in adipocytes compared with preadipocytes (P < 0.05). The relative mRNA abundance of ACE, ATM, calpain 1, SCD1, and 2 novel genes discovered in the current study was increased at the later stages of adipocyte differentiation (P < 0.05). The results confirmed that the genes involved in lipid metabolism and adipocyte differentiation were highly expressed in porcine adipocytes. However, further investigation is needed to demonstrate specific functions of the novel genes discovered in the current study.     

小麦对赤霉病抗性鉴定指标的探讨

连续3年用单花注滴法接种,考察了穗轴发病时间、病小穗数和穗轴病节片数3个抗性指标。结果表明,病小穗数这一指标能较明确地划分出高抗、中抗、感病3种类型,且稳定性最好。以病小穗数作为主要的抗病性鉴定指标,再参考穗轴病节片数,对小麦品种抗病性的评价及育种材料抗病性的鉴定较为准确、实用。     

Rapid enzyme-linked immunosorbent assay and colloidal gold immunoassay for kanamycin and tobramycin in Swine tissues

A monoclonal antibody (Mab) was produced by using the kanamycin-glutaraldehyde-bovine serum albumin (Kan-GDA-BSA) conjugate as the immunogen. The anti-Kan Mab exhibited high cross-reactivity with tobramycin (Tob) and slight or negligible cross-reactivity with other aminoglycosides. The specificity and cross-reactivity of this Mab are discussed regarding the three-dimensional, computer-generated molecular models of the aminoglycosides. Using this Mab, a rapid enzyme-linked immunosorbent assay (ELISA) and a colloidal gold-based strip test for Kan and Tob were developed. The rapid ELISA showed a 50% inhibition value (IC 50) of 0.83 ng/mL for Kan and 0.89 ng/mL for Tob with the analysis time less than 40 min, and the recoveries from spiked swine tissues at levels of 25-200 microg/kg ranged from 52% to 96% for Kan and 61% to 86% for Tob. In contrast, the strip test for Kan or Tob had a visual detection limit of 5 ng/mL in PBS, 50 microg/kg in meat or liver, and 100 microg/kg in kidney, and the results can be judged within 5-10 min. Observed positive samples judged by the strip test can be further quantitated by ELISA, hence the two assays can complement each other for rapid detection of residual Kan and Tob in swine tissues. Moreover, physical-chemical factors that affected the ELISA and strip test performance were also investigated. The effect of pH and antibody amount for gold-antibody conjugation on the strip test sensitivity was determined followed by a theoretical explanation of the effects.