Effect of Microsphaeropsis ochracea on Production of Sclerotia-borne and Airborne Conidia of Botrytis squamosa

Onion leaf blight, caused by Botrytis squamosa (Walker), is a destructive disease of onion. Conidia produced on overwintered sclerotia are the main source of initial inoculum, and those produced on lesions are responsible for secondary inoculum build-up. The biological control agent Microsphaeropsis ochracea (Carisse &; Bernier) was evaluated for its ability to control sclerotia-borne inoculum, to colonize onion leaves and reduce the production of conidia under field conditions. Colonisation by M. ochracea of onion leaves at different growth stages was monitored and its effect on B. squamosa sporulation on necrotic leaves was evaluated. Onion plots were treated with either Dithane® or with M. ochracea at 7–10-day intervals and according to inoculum production index (IPI). The concentration of airborne conidia and the number of lesions per leaf, on 20 plants per plot, were evaluated throughout the cropping season. The number of conidia produced per sclerotium treated with M. ochracea, was reduced by 75.5%. In the field, M. ochracea colonised only senescent or necrotic leaves and reduced the production of conidia on these leaves by an average of 82% as compared with untreated leaves. Best disease control was obtained by Dithane®, followed by M. ochracea applied at 7–10-day intervals. For the three years of the study, there were no significant differences in airborne concentrations of conidia in plots treated at 7–10-day intervals with Dithane® or M. ochracea. Fall application of M. ochracea could be used as a sanitation practice to reduce initial inoculum or as a part of an IPM program during the season.     

基于二维与三维信息的南京市主城区生态网络格局对比分析

生境破碎化导致生物多样性锐减,影响生境的生态系统服务,合理而有效的生态网络建设可以恢复城市内破碎生境斑块之间的连接。现有城市生态网络的构建与模拟多基于二维数据信息,未能很好地考虑植被三维结构信息所表征的多元生态位对生境质量的影响,致使生态网络的功能有效性有待验证。选取南京市主城区为研究区,基于高分辨率遥感影像与机载激光雷达数据,对研究区三维绿地植被结构进行了量化,在二维、三维两种情景下分别进行生态源地的提取与景观阻力面的设定,基于最小费用路径识别出两种情景下的生态廊道,并依据电路理论方法识别出廊道中需要重点保护的生态关键节点,进而分析使用二维、三维生态空间信息对生态网络构建结果产生的影响。研究结果表明:1)研究区不同情景下提取的生态源地共有11处不同,与传统二维情景下仅使用绿地面积指标作为斑块属性相比,使用三维植被参数可以更准确地识别具有丰富植被结构的生态源地;2)二维与三维情景下构建的生态廊道分别有137条与129条,平均每条廊道的单位距离阻力值分别为18.2与24.0,运用传统二维信息的模拟结果会在一定程度上高估研究区的景观连通性;3)不同情境下生态关键节点的空间分布基本一致,主要集中于研究区的西北侧、中部以及东南侧,并较多出现在距离较近的源地斑块之间。基于以上分析结果,有针对性地提出了南京市主城区生态网络格局优化的相关策略。     

BATHYMETRIC STUDIES ON THE PONGOLO RIVER FLOODPLAIN

SUMMARY

Thirteen of the major pans on the Pongolo river floodplain have been studied. Most are shallow (>2.5 m) and regularly lose up to 70% of their water each year, although few dry out. Floods inundate considerable areas (1000 ha) around pans situated in the flatter parts of the floodplain. Whilst inundated, these areas provide an allochthonous energy and nutrient source for the pan and, as the water levels recede, the exposed Cynodon dactylon (L.) Pers lawns provide grazing for cattle. The suitability of the various pans for fish production is discussed.     

2007～2011年鄂州市气传致敏真菌调查及其与支气管哮喘的相关性

目的 探讨2007年5月～ 2011年4月鄂州市气传致敏真菌和支气管哮喘关系,以了解该地区支气管哮喘情况.方法 运用暴片调查法和暴皿调查法统计和记录鄂州市气传致敏真菌的种类及数量.选择该时期内鄂州市100例支气管哮喘患者采用真菌变应原浸液作过敏原皮试发现有35例患者皮内试验阳性,将35例发作期患者和40例稳定期支气管哮喘患者行曲霉特异性IgE测定.结果 100例支气管哮喘患者皮内实验组阳性35例,阳性率为35％,而在35例患者中IgE阳性有31例,检测符合率为88.58％,稳定期患者中阳性反应例数2例,阳性率为5％,两组阳性率比较差异具有显著性（P＜0.05）.结论 鄂州市气传致敏真菌和支气管哮喘密切相关,主要致病菌为曲霉,是支气管哮喘的致敏原之一,需要注意环境卫生以减少气传致敏真菌的数量.     

Mesoscale Transport of Corylus Pollen Grains in Winter Atmosphere

Measurements of atmospheric pollen concentration were made at different sites of the Po Valley, Italy, during the winter of 1978. The concentration was determined with volumetric samplers both near the ground and at different heights up to 500 m. Only Corylus and Alnus pollen grains were found during the experimental period. Due to the large quantity of grains released and the detailed information available about the source areas, the Corylus pollen was used to investigate the features of atmospheric transport. It was found that the three-dimensional patterns of pollen concentration are strongly influenced by meteorological conditions. Moreover, it appears that pollen is present in the atmosphere for a longer time with respect to the emission period, due to the relevant effect of the resuspension of the deposited pollen grains. This effect is detectable at all the sampling points, and not only near the sources.     

Levels of Total Airborne Bacteria,Gram-Negative Bacteria,and Endotoxin According to Biosafety Levels in Korean Biosafety Laboratories

We assessed in this study the total airborne bacteria (TAB), gram-negative bacteria (GNB), and endotoxin (ET) concentrations in three Korean university laboratories and two hospital diagnostic laboratories categorized as biosafety level 1 (BL 1) or biosafety level 2 (BL 2). We also investigated the concentrations of TAB, GNB, and ET relative to the performance results of biosafety cabinets (BSCs). TAB and GNB were incubated, and ET was analyzed using the kinetic Limulus amebocyte lysate assay. A total of 246 (TAB = 95, GNB = 95, ET = 56) air samples were collected from nine laboratories. TAB, GNB, and ET concentrations were significantly higher in BL 1 laboratories and in laboratories that failed the BSC performance test compared to BL 2 laboratories and laboratories that passed the BSC performance test. Correlation coefficients were calculated to determine the relationships between TAB, GNB, and ET, and it was found that TAB significantly correlated with GNB (r = 0.35, p < .01) and ET (r = 0.29, p < .01). Careful attention needs to be paid to BL 1 laboratories, and BSCs should be managed on a regular basis to improve the air quality of university and hospital laboratories.     

Biosafety Assessment and Airborne Fungal Concentration as an Evaluation Index in University Laboratories and Hospital Diagnostic Korean Laboratories

This study evaluated both biosafety levels (BLs) and airborne fungal concentrations in microbiological laboratories in Seoul, Korea. To evaluate biosafety facilities, we used a checklist containing 67 questions in nine categories. We also measured airborne fungal concentration according to the BLs. Airborne fungal concentrations were higher in BL-1 facilities (240 CFU/m³) than in BL-2 facilities (25 CFU/m³). The airborne fungal concentrations significantly differed among the laboratories that were graded as poor, fair, and good. Especially, a significant negative correlation was observed between the airborne fungal concentrations and the biosafety levels (p = .001). We recommend that the guidelines of biosafety be followed to improve laboratory environment.     

Skin as a potential source of infectious foot and mouth disease aerosols

This review examines whether exfoliated, virus-infected animal skin cells could be an important source of infectious foot and mouth disease virus (FMDV) aerosols. Infectious material rafting on skin cell aerosols is an established means of transmitting other diseases. The evidence for a similar mechanism for FMDV is: (i) FMDV is trophic for animal skin and FMDV epidermis titres are high, even in macroscopically normal skin; (ii) estimates for FMDV skin cell aerosol emissions appear consistent with measured aerosol emission rates and are orders of magnitude larger than the minimum infectious dose; (iii) the timing of infectious FMDV aerosol emissions is consistent with the timing of high FMDV skin concentrations; (iv) measured FMDV aerosol sizes are consistent with skin cell aerosols; and (v) FMDV stability in natural aerosols is consistent with that expected for skin cell aerosols. While these findings support the hypothesis, this review is insufficient, in and of itself, to prove the hypothesis and specific follow-on experiments are proposed. If this hypothesis is validated, (i) new FMDV detection, management and decontamination approaches could be developed and (ii) the relevance of skin cells to the spread of viral disease may need to be reassessed as skin cells may protect viruses against otherwise adverse environmental conditions.     

京津冀地区气传花粉数据分析

花粉作为城市大气污染物成分之一, 严重影响人类的居住环境和生命健康, 是政府部门和科学界共同关注的热点问题。为此, 该文基于近60年来已发表的京津冀地区气传花粉数据, 总结了该地区主要气传花粉种类及其季节性分布特征, 表明气传花粉浓度的年际变化基本遵循双峰型规律, 即春季高峰以柏科、杨柳科和桦木科等乔木植物花粉为主, 夏秋季高峰以蒿属、葎草属/大麻(Cannabis sativa)以及藜科/苋科等草本植物花粉占优势; 探讨了影响气传花粉浓度的主导气象因子、花粉症发病特点等应当注意的问题; 指出土地改造和行道树种植等人类活动可能对北京地区的气传花粉组成变化产生影响。最后, 文中强调未来气传花粉的长期监测在大气环境评估、花粉过敏防治和城市绿化建设等方面具有重要作用。     

Amazon forest carbon dynamics predicted by profiles of canopy leaf area and light environment

Tropical forest structural variation across heterogeneous landscapes may control above‐ground carbon dynamics. We tested the hypothesis that canopy structure (leaf area and light availability) – remotely estimated from LiDAR – control variation in above‐ground coarse wood production (biomass growth). Using a statistical model, these factors predicted biomass growth across tree size classes in forest near Manaus, Brazil. The same statistical model, with no parameterisation change but driven by different observed canopy structure, predicted the higher productivity of a site 500 km east. Gap fraction and a metric of vegetation vertical extent and evenness also predicted biomass gains and losses for one‐hectare plots. Despite significant site differences in canopy structure and carbon dynamics, the relation between biomass growth and light fell on a unifying curve. This supported our hypothesis, suggesting that knowledge of canopy structure can explain variation in biomass growth over tropical landscapes and improve understanding of ecosystem function.