咖啡品种的特性及历史迁移

中国的咖啡规模化种植历史不足百年,从国外引进品种的渠道窄,品种少,规模化种植的品种不足20个,种植区对各品种的根源及特性了解也不多。阐述各品种的特性,为今后咖啡引种提供理论依据。     

Spatial and stochastic simulation to evaluate the impact of events and control measures on the 1997-1998 classical swine fever epidemic in The Netherlands. I. Description of simulation model

The simulation model InterCSF was developed to simulate the Dutch Classical Swine Fever (CSF) epidemic of 1997–98 as closely as possible. InterCSF is a spatial, temporal and stochastic simulation model. The outcomes of the various replications give an estimate of the variation in size and duration of possible CSF-epidemics. InterCSF simulates disease spread from an infected farm to other farms through three contact types (animals, vehicles, persons) and through local spread up to a specified distance. The main disease-control mechanisms that influence the disease spread in InterCSF are diagnosis of the infected farms, depopulation of infected farms, movement-control areas, tracing, and pre-emptive slaughter. InterCSF was developed using InterSpread as the basis. InterSpread was developed for foot-and-mouth disease (FMD). This paper describes the process of modifying InterSpread into InterCSF. This involved changing the assumptions and mechanisms for disease spread from FMD to CSF. In addition, CSF-specific control measures based on the standard European Union (EU) regulations were included, as well as additional control measures that were applied during the Dutch epidemic. To adapt InterCSF as closely as possible to the Dutch 1997/98 epidemic, data from the real epidemic were analysed. Both disease spread and disease-control parameters were thus specifically based on the real epidemic. In general, InterSpread turned out to be a flexible tool that could be adapted to simulate another disease with relative ease. The most difficult were the modifications necessary to mimic the real epidemic as closely as possible. The model was well able to simulate an epidemic with a similar pattern over time for number of detected farms as the real outbreak; but the absolute numbers were (despite many relevant modifications) not exactly the same — but were within an acceptable range. Furthermore, the development of InterCSF provided the researchers with a better insight into the existing knowledge gaps. In part II (see the final paper in this issue), InterCSF was used to compare various control strategies as applied to this epidemic.     

Assessing the role of long-distance translocation and spatial heterogeneity in the raccoon rabies epidemic in Connecticut

Spatial heterogeneity and long-distance translocation (LDT) play important roles in the spatio-temporal dynamics and management of emerging infectious diseases and invasive species. We assessed the influence of LDT events on the invasive spread of raccoon rabies through Connecticut. We identified several putative LDT events, and developed a network-model to evaluate whether they became new foci for epidemic spread. LDT was fairly common, but many of the LDTs were isolated events that did not spread. Two putative LDT events did appear to become nascent foci that affected the epidemic in surrounding townships.

In evaluating the role of LDT, we simultaneously revisited the problem of spatial heterogeneity. The spread of raccoon rabies is associated with forest cover—rabies moves up to three-times slower through the most heavily forested townships compared with those with less forestation. Forestation also modified the effect of rivers. In the best overall model, rabies did not cross the river separating townships that were heavily forested, and the spread slowed substantially between townships that were lightly forested. Our results suggest that spatial heterogeneity can be used to enhance the effects of rabies control by focusing vaccine bait distribution along rivers in lightly forested areas. LDT events are a concern, but this analysis suggests that at a local scale they can be isolated and managed.     

红脂大小蠹在中国成灾原因及扩散趋势分析

红脂大小蠹是我国一种危害油松等松树的外来入侵物种。国家林业局2005年已将该虫列入对内森林植物检疫对象名单。本文分析了该虫最初发生地的气候情况，探讨了气候因素对该虫发生的影响。结合红脂大小蠹在中国的潜在分布区，对该虫扩散趋势做出预测。提出了一些防治建议。     

玉米弯孢菌叶斑病传播梯度模型

 根据植物病害流行学原理,采用人工接种方法,在田间造成玉米弯孢菌叶斑病不同的发病梯度,分析连续2年玉米弯孢菌叶斑病传播动态。利用SPSS统计软件构建了此病害的传播梯度模型,结果表明指数模型是沈阳地区玉米弯孢菌叶斑病传播梯度的最佳模型。接种2个月,掖单13玉米弯孢菌叶斑病传播梯度最佳模型是x=9.606×EXP (-0.2829×d),海试16最佳模型是x=7.154×EXP (-0.2351×d)(x:病情指数,d:距菌源中心的距离)。预测玉米弯孢菌叶斑病在2个月最远传播距离为28 m;传播速度为0.4~0.5 m/d。     

Contribution of active defense responses in the limitation of fungal spread in the sapwood of living sugi (Cryptomeria japonica) tree

The participation of active defense responses in the limitation of fungal spread in the sapwood of living sugi tree was determined. Isolates ofGuignardia cryptomeriae were inoculated to living trees, fresh logs, frozen and thawed logs and autoclaved logs, and the spread of wood discoloration and fungal hyphae was assessed. In autoclaved logs and freeze-treated logs, wood discoloration and reaction zone formation were not observed, and fungal hyphae of both of virulent and avirulent isolates grew rapidly in the wood. In fresh logs, wood discoloration and the formation of a pale reaction zone and transition zone were observed. Virulent isolates spread rapidly, but the spread of avirulent isolates was inhibited. In living trees, wood discoloration was observed and reaction zones were formed at lesion margins. These results indicated that constitutive defense mechanisms had no effect on the spread of both of virulent and avirulent isolates, and that active defense responses were important in the limitation of spread of fungal hyphae, hence in the limitation of wood discoloration. Further, it appeared that avirulent, but not virulent, races ofG. cryptomeriae were easily inhibited even by weak host responses. This study was presented at 105th and 106th Annual Meeting of the Japanese Forestry Society.     

泡桐大袋蛾种群消亡成因的初步分析(英文)

对河南省兰考县１９８５ ～１９９５ 年泡桐大袋蛾治理情况、虫口密度以及寄生率的数据进行分析,结果表明：按受害面积可以将泡桐大袋蛾的发生划分为蔓延期（１９８５ ～１９９０） ,这时的年平均扩散速率为１１５ ％ ;高峰期（１９９１ ～１９９２） ,年平均扩散速率约为０ ％ ;消亡期（１９９３ ～１９９５） ,这期间大袋蛾种群急剧消亡．防治措施能有效保护泡桐叶片．但由于对有虫树木不能彻底地防治,因而不能有效防止害虫的扩散;同时,这种防治措施也不是导致大袋蛾种群消亡的原因．数据分析还表明大袋蛾的发生周期更象是与寄生天敌相互作用的结果,天敌的作用是大袋蛾种群消亡的促进因子之一,但不是决定性的因子．本文提出了泡桐大袋蛾种群破产阈值的观点,并计算得到破产阈值指标 Ｔｃｒ ＝ ３５５ 头／ 百叶,即当幼龄（１ ,２ 龄） 虫口密度超过３５５ 头／ 百叶、扩散速率为０ ％ 时,大袋蛾种群将自然、迅速地消亡．因为极高的虫口密度导致了剧烈的种内竞争,并且环境负荷量已无法满足种群的需要．     

长江中下游小麦抗赤霉病品种的筛选与部分农艺性状分析

【目的】 赤霉病严重危害中国乃至世界小麦的产量和品质,培育和种植抗病品种是控制赤霉病最经济、有效和安全的方法。Fhb1是国内外公认的抗赤霉病主效基因,通过筛选综合农艺性状优良的抗赤霉病品种,探明Fhb1在不同遗传背景下对小麦赤霉病抗性的影响,为小麦抗赤霉病育种提供理论依据和材料来源。【方法】 选取历年来长江中下游广泛种植的75份小麦改良品种和18份地方品种,2016—2018年连续3年采用单花滴注结合弥雾保湿进行供试品种的赤霉病抗扩展鉴定,根据3年平均病小穗率和严重度分级,将供试品种分成抗病（R级）、中抗（MR级）、中感（MS级）和感病（S级）,并利用Fhb1的KASP标记检测;2019年调查筛选出的平均赤霉病抗性水平达到中感及以上小麦品种的株高、穗粒数、小穗数、穗长和千粒重。【结果】3年赤霉病鉴定结果表明,供试品种中有2个品种平均赤霉病抗性达到R级,平均病小穗率范围为7.8%—9.7%,65个品种达到中抗至中感,平均病小穗率范围为13.2%—49.5%,26个品种达到S级,平均病小穗率范围为53.6%—78.5%。22个小麦品种在Fhb1位点呈抗病基因型（简称Fhb1+）,71个品种在该位点呈感病基因型（简称Fhb1-）,Fhb1+品种平均病小穗率显著低于Fhb1-品种（P<0.05）。赤霉病鉴定筛选得到67个抗性达到中感及以上水平的品种,考察这些品种的农艺性状发现宁麦19、扬麦29、扬麦16、扬麦23、扬糯麦1号、扬麦20、宁麦12和扬辐麦4号的株高、穗粒数和千粒重等综合农艺性状优良,可作为小麦抗赤霉病育种的亲本选用。【结论】除苏麦3号和望水白外,供试材料中未发现其他高抗赤霉病的种质资源。筛选得到的赤霉病抗性与综合农艺性状结合较好的小麦品种以扬麦品种为主,其中只有扬辐麦4号携带Fhb1抗病基因。利用Fhb1抗病基因并不是解决小麦赤霉病危害的唯一途径。     

Cuticular calcium penetration is directly related to the area covered by calcium within droplet spread area

Calcium penetration from salt solutions of calcium chloride and calcium acetate was measured through isolated tomato fruit (Solanum lycopersicum L., cultivar ‘Panovy’) cuticles after 4, 24, and 48 h. Droplet spread area (volume = 1 μL) and the area ultimately covered with calcium were determined with a scanning electron microscope which has an integrated energy dispersive X-ray microanalysis system. An ethoxylated rapeseed oil surfactant (RSO 5) was used for inducing different degrees of droplet spread and together with different calcium concentrations of the solutions to vary the concentration gradient in the penetration experiments. As a rule, penetration of calcium from CaCl₂ was higher than that of Ca(CH₃COO)₂. The addition of RSO 5 to salt solutions resulted in enhanced calcium penetration in comparison to unformulated solutions. However, extending penetration time from 4 to 48 h predominantly did not enhance the penetrated calcium amount significantly. Droplet spread area was enhanced up to 4-fold after adding RSO 5, whereas the area ultimately covered with calcium did not exceed twice as much. This resulted in lower percentage area covered by calcium in droplet footprints from formulated solutions in comparison to solutions without addition of RSO 5. Correlation analyses showed that penetration was not related to droplet spread area but significantly correlated with the area covered by calcium. These observations were true for unformulated calcium salts as well as for calcium solutions with addition of RSO 5. Therefore, the area ultimately covered with calcium or even other xenobiotics within a droplet footprint should be considered in developing mathematical models to simulate active ingredient (a.i.) penetration.     

一种基于Web挖掘的远程教学系统的研究与实现

通过Web日志挖掘与内容挖掘的有机结合,给出了一种个性化远程教学系统的模型,通过分析学生的兴趣给出相应的导航推荐,为学生提供个性化的教学服务,使得整个教学活动成为丰富有机的整体。