奇异交叉谱分析方法在中国南方稻纵卷叶螟发生预测中的应用

利用奇异交叉谱分析方法(SCSA),对中国南方水稻主产区中广西全州、重庆秀山、湖南湘阴和江苏张家港4个代表站点1994-2014年稻纵卷叶螟田间逐日赶蛾量资料和与4站虫量相关性最显著的环流因子进行耦合周期分析,通过重建耦合分量序列(RCCS)对分量序列的时间变化特征进行探讨,并采用SCSA-AR方法对稻纵卷叶螟发生量进行外推预测。结果表明:预测结果与实际情况基本吻合。对预测平均误差(ME)、平均绝对误差(MAE)、均方根误差(RMSE)及预测值与实况值的符号相关率(RSC)进行计算,4站综合平均的ME为-0.071、MAE为0.349、RMSE为0.446、RSC为0.75,表明预测误差较小,预测序列较稳定,预报精度较高,可将此方法推广应用于中国南方稻区稻纵卷叶螟的发生趋势预测。     

典型冶炼厂大气沉降区农田耕层土壤重金属（Cd、Cu、Pb）输入输出平衡研究

为探究不同大气沉降区农田耕层土壤镉（Cd）、铜（Cu）、铅（Pb）的质量平衡特征,以距离贵溪冶炼厂34 km（背景区）、6 km（中沉降区）、1 km（高沉降区）的0~20 cm农田耕层土壤为研究对象,通过化学质量平衡方法对土壤重金属的主要输入途径（大气沉降、灌溉水、农药肥料）和输出途径（地表径流、土壤淋溶、籽粒带走）开展为期三年的监测与定量分析。结果表明：背景区、中沉降区、高沉降区由大气沉降导致的Cd年均输入通量分别为0.84、2.26、9.01 mg?m-2?a-1,分别占比43.18%、38.33%、100%;Cu年均输入通量分别为17.62、99.68、747.6 mg?m-2?a-1,分别占比80.76%、86.24%、100%;Pb年均输入通量分别为13.93、27.43、73.17 mg?m-2?a-1,分别占比97.75%、92.36%、100%。背景区和中沉降区由灌溉水导致的Cd年均输入通量分别为1.05、3.60 mg?m-2?a-1,分别占比54.62%和60.82%;农药肥料带入的重金属年均输入量占比小于5%,可忽略不计。不同沉降区土壤的主要输出途径均为地表径流和土壤淋溶,输出占比介于86.66%~100%;籽粒带走的重金属输出占比介于2.88%~13.34%。2019—2021年,背景区、中沉降区、高沉降区土壤Cd、Cu、Pb的年均净输入通量均大于0,Cd年均净输入通量分别为1.54、1.96、4.38 mg?m-2?a-1;Cu年均净输入通量分别为12.72、28.02、184.0 mg?m-2?a-1;Pb年均净输入通量分别为13.03、21.31、55.04 mg?m-2?a-1。综上,建议加强研究区域大气污染源和灌溉水质的长期监测并采取一定的控制措施,同时避免秸秆直接还田。本研究可为区域农田环境质量保护及重金属污染修复治理提供理论支持。     

Research on the horizontal reduction effect of urban roadside green belt on atmospheric particulate matter in a semi-arid area

In this study, the horizontal abatement effects of green belts on atmospheric particulate matter at different horizontal distances and plant community structures were investigated in urban roadside green belts in semi-arid areas.We collected mass concentrations of six types of atmospheric particulate matter (PM) per unit time of PM_0.3, PM_0.5, PM_1.0, PM_2.5, PM_5.0, and PM₁₀ and various meteorological indices, to compare the horizontal reduction efficiency of different distances and plant community structures on different particle sizes, and to establish a support vector machine model. The results showed that 1) the horizontal abatement efficiency of green belts was different for six particle sizes, while the horizontal abatement rate strengthened as the particle size increased. The abatement rate was significantly correlated with microclimatic factors such as temperature and humidity, but less correlated with wind speed. 2) The horizontal abatement rate of roadside green belts on atmospheric particulate matter varies with the increase of horizontal distance in a "single-peak" or "double-peak" pattern, with the best abatement effect of green belts on each particle size at a horizontal distance of 45m. Among the four types of plant community structures, the strongest abatement ability was in the arbor-shrub-herb structure. 3) The correctly tuned prediction model, based on Support Vector Machines, resulted in better horizontal abatement ability of green belts on atmospheric PM. The prediction results showed that the average horizontal abatement rate has the best abatement effect at 45–55 m, peaked at 50 m, and formed stagnant dust at 65 m. In the design of urban road green spaces in semi-arid areas, to achieve the best dust retention effect, the green belt width should be ≥40 m and it is desirable to choose arbor-shrub-herb structures. This study provides a design basis and theoretical support for urban road green space planning in semi-arid areas.     

基于粒度方法的大气降尘对浙江省新嵊盆地土壤的物源输入研究

为揭示大气降尘对亚热带季风区土壤资源的影响,本文以亚热带地区典型玄武岩发育土壤为研究对象,采用土壤地理学和土壤粒度分析方法,分析表层土壤样品的粒度组成、粒度频率曲线和高含量的"风尘基本粒级"(10～50μm)的粒度分布特征,结果表明大气降尘对土壤表层的影响深远。土壤Sr-Nd同位素比值辅助证据也进一步说明表层也不断受到来自大气降尘的影响。研究剖面土壤表层样品的粒度组成、频率曲线、粒度参数和Sr-Nd同位素比值均指示显著的风尘特性,而底土层土壤样品则大多数继承了母岩的特性。揭示了大气降尘对该区域土壤资源的重要补给作用和对土壤发生演变的重要影响。     

常温常压等离子体诱变选育安普霉素高产菌株

安普霉素作为一种广谱兽用抗生素，对多种革兰氏阴性菌、阳性菌和某些支原体具有较好的抗菌作用。本论文利用常温常压等离子体(ARTP)技术结合抗性筛选方法，对安普霉素产生菌黑暗链霉菌进行诱变选育，以期得到高产菌株。以AP-520为出发菌，进行ARTP诱变处理，ARTP最佳诱变时间是70 s,处理后的菌液在潮霉素平板上进行抗性筛选，单菌落经过48孔板大量筛选后再进行摇瓶初筛和复筛，共进行8轮筛选试验，得到一株高产菌株AP-6023,摇瓶效价达到11444 U·ml^-1,较对照提高29%,经过10次传代培养后仍能保持产抗能力，30 L发酵罐效价为10920 U·ml^-1,较对照提高23%。突变株AP-6023的获得，大大提高了安普霉素的生产水平，证实了ARTP诱变技术的有效性，试验方法为其它工业微生物的育种提供了解决思路。     

Review on the multi-scale interactions of urban forests and atmospheric particles: Affecting factors are scale-dependent among tree,stand and region

Increasing studies worldwide have examined the impacts of urban forests on mitigating atmospheric particulate matter (PM) over the past decades. These scattered studies revealed the aerodynamics of atmospheric PM deposited on urban forests, as well as the various factors influencing the PM capture and removal by urban forests. However, these evidences are varying and even contradictory, and the affecting factors do not follow a universal pattern. In addition, these studies generally have been conducted in a specific scale such as leaf, stand and city without considering the multi-scale associations and incorporations. This literature review tried to address the associations of urban forest and PM removal across single tree, stand and regional scales, and summarized the confounding factors for PM capture and removal within each scale. Particle size and local meteorology have significant impacts across scales. For an individual tree, PM capture and removal capacity are largely determined by the leaf morphology and epidermal structures, but at the stand scale, the biophysical characteristics and configurational designs of urban forests are the essential factors. At the city and regional scale, the determinants are the fraction of forest coverage, as well as background pollution levels. The literature collation emphasizes the necessity of concerning the appropriate factors responding to the specific scale when quantifying and evaluating PM capture and removal by urban forests, and warrants a multi-scale research paradigm and inclusive modeling evaluation incorporating the confounding factors from multiple scales for PM capture and removal by urban forests.     

森林土壤氧化亚氮排放对大气氮沉降增加的响应研究进展

森林土壤N2O来源于土壤氮素的氧化还原反应,硝化、反硝化、硝化细菌反硝化以及化学反硝化是其产生的四个关键过程。当前,氮素富集条件下森林土壤N2O排放存在硝化和反硝化主导作用之争,对大气氮沉降增加的响应模式以及微生物驱动机制尚不清楚。综述了森林土壤N2O来源的稳定性同位素拆分,森林土壤总氮转化和N2O排放对增氮的响应规律,增氮对N2O产生菌群落活性和组成的影响,并指出研究的薄弱环节与未来的研究重点。总体而言,森林土壤N2O排放对大气氮沉降增加的响应呈现非线性,包括初期无明显响应、中期缓慢增加和后期急剧增加三个阶段,取决于森林生态系统"氮饱和"程度。施氮会引起森林土壤有效氮由贫氮向富氮的转变,相应地改变了土壤硝化细菌和反硝化细菌群落丰度与组成,进而影响土壤N2O排放。由于森林土壤N2O排放监测、土壤总氮转化和N2O产生菌群落动态研究多为独立进行的,难以阐明微生物功能群与N2O排放之间的耦合关系。未来研究应该有机结合15N-18O标记和分子生物学技术,准确量化森林土壤N2O的来源,揭示森林土壤N2O排放对增氮的非线性响应机理。