正交设计结合响应面法优化榆黄蘑液体发酵的研究

通过对榆黄蘑液体发酵的单因素试验,并结合使用正交设计和响应面法2种实验设计方法,确定榆黄蘑液体发酵的最适培养基配方和最适培养条件。结果表明,榆黄蘑液体发酵的最适培养基配方为葡萄糖1.00%、蔗糖1.00%、蛋白胨0.3%、KH₂PO₄ 0.15%、氯化钠0.03%、MgSO₄ 0.07%、V_B1 0.001%;最适培养条件是接种量5 %、250 mL的锥形瓶装液量150 mL、温度27 ℃、初始pH值6.55及转速155 r·min^-1。     

Climatic response and impacts of drought on oaks at urban and forest sites

This study focuses on the climate and growth response of the sessile oak (Quercus petraea (Matt.) Liebl.) and the northern red oak (Quercus rubra L.) using dendrochronological methods. Tree-ring series of street trees in the city of Dresden, Germany and in a nature reserve close to the urban area were analysed, and the climate and growth response and moving correlation functions (CF) were computed. Moreover, the impact of 13 years of drought was examined by superposed epoch analysis (SEA). Our results show that differences emerge from peculiarities of the different site conditions, indicating that city oaks contain a higher level of noise in their ring width data due to human activities that degrade the strength of growth-climate associations. Importantly, climatic conditions during the previous summer and autumn and during the current spring season display significant correlations with annual growth. The stability of the climate–growth relationship was tested via moving correlation functions. A strong increase in the correlation with the temperature and precipitation in April was found for the trees of northern red oak in forests. Drought years induced significant reductions in radial growth for the northern red oak only. Nevertheless, the long-term impact of drought years must be considered as marginal because of the fast recovery of the radial growth after one to two years. In the future, the growth of the northern red oak may be restricted by an increased frequency of droughts and warmer and drier conditions in April.     

海洋食物网结构稳定性及干扰响应研究综述

针对当前全球环境急剧变化的背景,本文归纳了海洋食物网结构复杂性常用的量化指标,梳理了食物网稳定性不同维度的概念并深入探究其与复杂性之间的内在联系。根据海洋生态系统的不同干扰类型,分析了各种类型干扰的发生方式以及食物网在应对干扰时的适应机理,最后总结了海洋生态系统数据获取分析以及食物网构建时有待解决的问题,并指出开展初级生产者与消费者之间的相互作用研究能更利于解析全球变化对海洋食物网结构和功能的影响。     

The predictive control of an incremental model based on tracking error

An algorithm of incremental model predictive control is proposed to solve a class of industrial production process real-time tracking problems. The basic idea is to establish a predictive model by adopting speed response on the basis of tracking error, and realize the optimization of the second time performance by using the soft constraint of the increment of control quantity and the online rolling optimization method. The theoretical analysis and Matlab simulation results show that the control algorithm can obtain good tracking performance, smooth dynamic response of the controlled object and strong robustness of the closed-loop system.     

响应面法优化陇南黄樱桃低糖保健酱配方研究

以陇南黄樱桃鲜果为原料,添加黄果槲寄生果实多糖等材料进行加工,研制低糖复合果酱.通过单因素试验,对黄樱桃果肉含量、木糖醇和柠檬酸添加量及黄果槲寄生果实多糖添加量进行筛选.根据感官评分,采用Box-Benhnken中心组合设计试验,优化陇南黄樱桃低糖保健酱的配方.结果表明,低糖陇南黄樱桃保健酱的配方为:黄樱桃果肉61.28％,木糖醇16.19％,柠檬酸0.18％,黄果槲寄生果实多糖0.33％,氯化钙0.02％,D-异抗坏血酸钠0.10％,由该配方制得的陇南黄樱桃低糖保健酱色鲜黄,有光泽,甜酸适口,组织状态良好,可溶性固形物含量55.54％,总糖含量34.36％,pH 3.86,黏度25.89 cm/30 s.     

Spatial Variability of Corn Yield and Yield Response to Fertilizer Nitrogen: Role of Organic Carbon

Utility of organic carbon (OC) content as an indicator of corn (Zea maize L.) grain yield and yield response to nitrogen (N) across a broad range of conditions was assessed using data from two studies (the first on a variable landscape at Elora Research Station and the second on 19 landscapes in private farms) conducted from 1998 to 2003 in southern Ontario. Zero and 140/150 kg N ha^?1 were applied in all studies. Yields generally increased linearly or quadratically with increasing OC. Regression models indicated 42% of the data sets had no response to fertilizer N and in only two data sets in Elora and no data sets in private farms were yield responses to N dependent on OC. When yield increased with fertilizer addition, it was similar for all OC contents in a landscape. We concluded that OC content cannot be used to identify N-management units in southern Ontario.     

Grain yield,growth response,and water use efficiency of direct wet-seeded rice as affected by nitrogen rates under alternate wetting and drying irrigation system

ABSTRACT

The present investigation aimed to determine the effectiveness of different nitrogen (N) rates on grain yield, growth, and water use efficiencies of direct wet-seeded rice and to create a relationship of N rates with growth parameters and dry matter production at different stages. The experiments compared six rates of nitrogen (0, 40,80,120,160, and 200 kg ha^–1N) replicated thrice in randomized complete block design in two conjunctive years of 2009–2010 and 2010–2011 at Bangladesh Rice Research Institute farm, Gazipur.The highest grain yield of 7.85 and 7.22 t ha^?1 was observed in N₂₀₀ treatment in 2009–2010 and 2010–2011, respectively. The relationship (R²) of total dry matter with leaf area index , leaf area duration, and crop growth rate indicated strong association during booting stage to achieved maximum dry matter during harvest. Water use efficiency varied 87–91% in different N levels.     

Oxidative Stress Induced by Cadmium and Copper in Brassica rapa Leaves: Indicators of Stress,Oxidative Damage,and Antioxidant Mechanisms

Brassica rapa is frequently used as a vegetable for human consumption and can accumulate metals that are bioavailable in soils. We studied the oxidative stress induced by 25 μM cadmium (Cd) and 50 μM copper (Cu) on Brassica rapa leaves and evaluated the intracellular antioxidative plant response mechanisms and the accumulation of these metals. With this purpose, hydrogen peroxide (H₂O₂) concentration, lipid peroxidation, and enzymatic and nonenzymatic responses was determined. The obtained results indicate that Cd and Cu induced different plant responses. Oxidative stress induced by Cu was characterized by increased lipid peroxidation and free proline levels. Guaiacol peroxidase and ascorbate peroxidase showed a relevant role in H₂O₂ removal. Cadmium did not influence lipid peroxidation, H₂O₂, proline and glutathione contents, and the enzymatic response mainly involves superoxide dismutase and ascorbate peroxidase. It was concluded that both excess Cu and Cd induced oxidative stress but plant response is characterized by different antioxidative response mechanisms.     

Correlation between Solvita Labile Amino-Nitrogen and CO2-Burst Soil Health Tests and Response to Organic Fertilizer in a Turfgrass Soil

ABSTRACT

The Solvita Soil Labile Amino-Nitrogen (SLAN) and Soil CO₂-Burst (SSCB) tests are used in soil health assessments. Field experiments were conducted from 2014–2016 in Connecticut, USA to: (1) determine if SLAN and SSCB concentrations are correlated for a sandy loam soil under predominately Kentucky bluegrass (Poa pratensis L.) and tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.] turfgrass lawns, and (2) compare the response of SSCB–C and SLAN–N concentrations in relation to varying rates of an organic fertilizer. Concentrations of SLAN–N were positively and significantly (P < .001) correlated with concentrations of SSCB–C for all years, both species, and combinations of years and species (r = 0.477 to 0.754). The response of SSCB–C and SLAN–N concentrations to organic fertilizer rates were positively linear and significant (P < .01) in all cases but one (2014 tall fescue SSCB–C concentrations). Rates of change across fertilizer rates were generally greater for SLAN–N concentrations. There was greater variation within the SSCB test than within the SLAN test. The results suggest that the SLAN and SSCB tests are well-correlated and both may be able to provide an estimate of a turfgrass soil’s N mineralization potential.