乙酰氨基阿维菌素缓释注射剂中乙酰氨基阿维菌素含量与有关物质HPLC检测方法的建立

试验旨在建立一种高效液相色谱检测方法,同时测定乙酰氨基阿维菌素(EPR)缓释注射剂的主成分与有关物质,采用外标法计算主成分的含量,采用自身对照法计算有关物质的含量。色谱柱为Phenomenex Luna 5 μ-C8-100A 250 mm×4.60 mm,5 μm;色谱条件为:流动相为乙腈-0.1%高氯酸水溶液,梯度洗脱,流速为1.5 mL/min,检测波长为245 nm,柱温为35 ℃,进样量为20 μL。结果表明,EPR缓释注射剂主成分与杂质分离度良好,B1a与B1b之间分离度>3;在EPR浓度为1.5625~1 000 μg/mL的范围内线性关系良好;EPR的检测限与定量限分别为0.01和0.34 μg/mL,3种精密度的相对标准偏差(RSD)均<2%,稳定性的RSD为0.28%,加样回收率为102.54%,且RSD为3.14%(n=9)。耐用性试验表明,EPR缓释注射剂主成分的分离度均>1.5,理论塔板数>4 500,表明该检测条件的耐用性良好。3批样品中,EPR缓释注射剂含量的平均值为102.60%,B1b占B1a与B1b之和的1.68%,总杂质的平均含量为2.57%。建立的EPR缓释注射剂中主成分含量与有关物质的测定方法具有简便、专属性强、灵敏度高、结果准确等特点,可用于EPR缓释注射剂的质量控制。     

Size- and leaf age-dependent effects on the photosynthetic and physiological responses of Artemisia ordosica to drought stress

Drought is one of the most significant natural disasters in the arid and semi-arid areas of China. Populations or plant organs often differ in their responses to drought and other adversities at different growth stages. At present, little is known about the size- and leaf age-dependent differences in the mechanisms of shrub-related drought resistance in the deserts of China. Here, we evaluated the photosynthetic and physiological responses of Artemisia ordosica Krasch. to drought stress using a field experiment in Mu Us Sandy Land, Ningxia Hui Autonomous Region, China in 2018. Rainfall was manipulated by installing outdoor shelters, with four rainfall treatments applied to 12 plots (5 m×5 m). There were four rainfall levels, including a control and rainfall reductions of 30%, 50% and 70%, each with three replications. Taking individual crown size as the dividing basis, we measured the responses of A. ordosica photosynthetic and physiological responses to drought at different growth stages, i.e., large-sized (>0.5 m²) and small-sized (≤0.5 m²) plants. The leaves of A. ordosica were divided into old leaves and young leaves for separate measurement. Results showed that: (1) under drought stress, the transfer efficiency of light energy captured by antenna pigments to the photosystem II (PSII) reaction center decreased, and the heat dissipation capacity increased simultaneously. To resist the photosynthetic system damage caused by drought, A. ordosica enhanced its free radical scavenging capacity by activating its antioxidant enzyme system; and (2) growth stage and leaf age had effects on the reaction of the photosynthetic system to drought. Small A. ordosica plants could not withstand severe drought stress (70% rainfall reduction), whereas large A. ordosica individuals could absorb deep soil water to ensure their survival in severe drought stressed condition. Under 30% and 50% rainfall reduction conditions, young leaves had a greater ability to resist drought than old leaves, whereas the latter were more resistant to severe drought stress. The response of A. ordosica photosynthetic system reflected the trade-off at different growth stages and leaf ages of photosynthetic production under different degrees of drought. This study provides a more comprehensive and systematic perspective for understanding the drought resistance mechanisms of desert plants.     

Effects of rodent-induced disturbance on eco-physiological traits of Haloxylon ammodendron in the Gurbantunggut Desert,Xinjiang, China

Disturbance by rodents alters the morphologies and nutrients of plants as well as the physical-chemical properties of the soils. Changes in plants are considered to be mechanisms of defense against the disturbance by rodents. Rodents gnaw on the assimilating branches of Haloxylon ammodendron(CA Mey.) Bunge and burrow under the bushes in the desert ecosystems of Xinjiang, China. However, eco-physiological responses of different age groups of H. ammodendron to the disturbance by rodents are not well understood. In this study, soil physical-chemical properties under the shrubs and the above-ground morphological, physiological and biochemical features of assimilating branches of H. ammodendron of different age groups(i.e., young, 30-100 cm; middle-aged, 100-200 cm; and mature, 200 cm) in burrowed and non-burrowed(control) areas were studied in 2018. We found that disturbance by rodents significantly increased the crown width and total branching rates of young and middle-aged H. ammodendron. Photosynthetic pigment contents of assimilating branches of H. ammodendron were significantly reduced under the disturbance by rodents. In term of plant nutrients, the main differences among different age groups of H. ammodendron under the disturbance by rodents occurred in the total soluble sugar and reducing sugar contents that decreased in young plants, increased in middle-aged plants, and did not affect in mature plants. Crude protein and phosphorus contents significantly increased, while crude fiber and calcium contents significantly decreased in young plants. Crude fat and calcium contents significantly decreased in middle-aged plants. Soil organic matter(SOM), total nitrogen(TN), available nitrogen(AN) and available potassium(AK) contents in the topsoil(0–20 cm), which are conducive to forming 'fertile islands' ', also increased under the disturbance by rodents. In particular, soil AN and AK were the major factors affecting the above-ground morphological characteristics of H. ammodendron in burrowed areas. Overall, the response and defense strategies of H. ammodendron to the disturbance by rodents differed among different age groups, and the effect of the disturbance by rodents on H. ammodendron gradually weakened with the increasing plant age.     

西瓜细菌性果斑病菌基因Aave-3192和Aave-2108的功能研究

从本实验室构建的西瓜细菌性果斑病菌菌株A13的Mini-Tn5转座子突变体库中筛选出2株致病性丧失的突变菌株166和167,亚克隆及测序结果表明,突变株166和167的Tn5插入位点基因编号分别为Aave-3192和Aave-2108。为了进一步明确这2个基因的功能,分别对这2个基因进行互补。生物学试验结果表明,互补菌株恢复对西瓜果实的致病性,且在游动性、群体感应、胞外多糖、生物膜等性状上部分恢复至野生菌株A13的水平,表明这2个基因与该病菌在西瓜上的致病性相关。     

Application of the Berthelot reaction to the determination of ammonium‐N in soil extracts and soil digests

Abstract

The phenol‐hypochlorite‐ammonium reaction of Berthelot can be utilized in manual procedures for the analysis of NH₄‐N in a variety of soils applications, including total N measurement in soils, particle size separates and soluble organic matter fractions, and in measuring NH₄‐N in soil extracts. A simple, convenient, and versatile procedure is described.     

The effect of plant age and soil amendments on severity of phytophthora root rot of pepper (Capsicum annuum L) in South Western Nigeria

The incidence and severity of pepper Capsicum annuum to phytophthora root rot caused by Phytophthora infestan in Southwestern Nigeria was investigated. Root rot incidence and severity was significantly reduced with increase in the plant age. The highest level of root rot, of 81.7% and 67.6% obtained in 4 and 6 weeks old pepper plants were reduced to 25% and 5% in 10 and 12 weeks old pepper plants respectively. The resistance of the pepper plant to root rot severity increased with age. The result also showed that amendments of the soil with chicken manure wood ash and neem leaf suppressed the root rot incidence and severity of disease in the pepper plant.     

季节因素和供体年龄对辣椒小孢子培养的影响

以N24为试验材料,在不同季节和植株开花时期进行小孢子培养,研究季节因素和供体年龄对辣椒小孢子培养的影响。结果表明,辣椒小孢子胚性化反应受供体季节因素的影响较大,夏季的胚状体产率是冬季的2.3倍,但褐化率和污染率均较高;供体年龄也是影响辣椒小孢子培养的重要因素,夏季的最佳培养时期为始花15～30d,最高胚状体产率为13.56%,冬季的最佳培养时期为始花45～60d,最高胚状体产率为5.14%。     

脂麻秆中纤维素与半纤维素的含量测定

目的：测定脂麻秆中纤维素与半纤维素的含量。方法：重铬酸钾氧化法、碱提取法和差重法。结果：脂麻秆中纤维素含量约为37％，半纤维素含量约为50％。结论：脂麻秆中含有丰富的木质纤维素来源，其中纤维素含量与玉米秆、麦秆、稻秆相当，而半纤维素的含量要高，可加以综合利用。     

Climate‐driven population dynamics of a North American freshwater fish,Ictalurus furcatus: inference from the mitochondrial control region sequence data

Abstract – Using the Bayesian coalescent methodology and mitochondrial control region sequence data, the present study reconstructs the dynamics of effective population size of a temperature‐driven seasonal migratory North American freshwater fish, Ictalurus furcatus, during the last glacial cycle. The trend in effective population size is directly associated with the trend in surface air temperature; it is inversely associated with the accumulation of ice sheets in North America during the contemporary period. The long‐term decrease in effective population size during the cold period followed by rebound during the warmer period could be explained by this species’ preference for relatively warmer temperatures for its optimal growth and survival.