Resistance to Leveillula taurica in the genus Capsicum

One hundred and sixty-two Capsicum genotypes were evaluated for powdery mildew (Leveillula taurica) resistance, following inoculations with a suspension of 5 × 10⁴ conidia mL⁻¹ on 10-leaved to 12-leaved plants. Genotypes were graded into five resistance classes, based on the areas under the disease progress curves calculated from disease incidence (percentage infected leaves per plant) and severity (total number of colonies per plant). Results revealed a continuum from resistance to susceptibility, with the majority (70%) of C. annuum materials being classified as moderately to highly susceptible to L. taurica. Conversely, C. baccatum, C. chinense and C. frutescens were most often resistant, indicating that resistance to L. taurica among Capsicum species is found mainly outside the C. annuum taxon. Nevertheless, some resistant C. annuum material was identified that may be useful for resistance breeding. Eight genotypes were identified as immune to the pathogen: H-V-12 and 4638 (previously reported), and CNPH 36, 38, 50, 52, 279 and 288. Only H-V-12 and 4638 are C. annuum, while all others belong to the C. baccatum taxon. Latent period of disease on a set of commercial sweet pepper genotypes varied, indicating diverse levels of polygenic resistance. The latent period progressively reduced with plant maturity, from 14·3 days in plants at the mid-vegetative stage to 8·6 days in plants at the fruiting stage. Young plants of all commercial genotypes tested at the early vegetative stage were immune, irrespective of the reaction of the genotype at later stages, demonstrating widespread juvenile resistance to L. taurica in the Capsicum germplasm. Inoculation of plants of different botanical taxa with a local isolate indicated a wide host range. Some hosts, including tomato (Lycopersicon esculentum), artichoke (Cynara scolymus) and poinsettia (Euphorbia pulcherrima), produced large amounts of secondary inoculum. Other hosts included okra (Abelmoschus esculentus), eggplant (Solanum melongena), cucumber (Cucumis sativus), Solanum gilo, Chenopodium ambrosioides and Nicandra physaloides.     

新疆地区参考作物腾发量的灰色模型预测

该文依据新疆地区6个站的长序列逐日气象观测资料,基于Penman-Monteith公式计算了逐日参考作物腾发量（ET0）,并应用重标极差法对ET0未来变化趋势进行了分析。运用灰色关联理论计算了各站各气象因子与年ET0间的灰色关联度和关联序。在此基础上,运用灰色系统理论建立灰色不等维递补GM（1,h）模型对6个站的年ET0进行了模拟预测,并与灰色GM（1,1）模型进行了比较。结果表明：各站ET0年内变化均呈抛物线型,4－9月ET0依各站顺序为：若羌＞吐鲁番＞哈密＞喀什＞和田＞伊宁;6站年ET0赫斯特指数均大于0.5,各站未来的趋势与历史呈正相关,依然是波动递减;总体上,平均温度、日照时数、饱和气压差对各站年ET0的影响比较大;灰色不等维递补GM（1,h）模型预测相对误差限为0～7.31%,预测精度明显高于GM（1,1）模型。该研究表明采用灰色模型预测新疆地区参考作物腾发量精度较好。     

Ecological features and ranging patterns at a chimpanzee release site on Rubondo Island, Tanzania

This study examines the behavioral ecology of a chimpanzee population on Rubondo Island in Lake Victoria, Tanzania, over 40 years after chimpanzees were first introduced to the island from captivity. Despite little pre-release habitat assessment, rehabilitation, or post-release monitoring, these chimpanzees are one of the only released populations to survive over decades without provisioning. We surveyed habitat structure and plant composition to gain insights into ecological features that have supported this self-sufficient chimpanzee population for over 40 years. We also examined possible ecological sources of chimpanzee ranging patterns on the island. We surveyed woody plant composition, and quantified densities of species producing large fleshy fruits and confirmed chimpanzee fruit foods across three chimpanzee ranging areas, each separated by several kilometers. We used non-metric multidimensional scaling (NMS) ordination to compare community-level patterns of plant composition across regions. The densities of trees and lianas producing fleshy fruits were high in comparison with similar measures at endemic chimpanzee study sites. There were major differences in the composition of tree species, including species of chimpanzee fruit foods, across the three regions. In contrast, liana species composition was similar across regions, and was characterized by a few super-abundant species, including one chimpanzee fallback food. The wide-ranging patterns of chimpanzees do not appear to be influenced by localized tree fruiting patterns, but may be facilitated by the wide-spread distribution of an important fallback food. In comparison with other endemic and release sites, the relatively low ecological population density of chimpanzees, the high density of both trees and lianas producing large fleshy fruits and the presence of a high-quality, widely-distributed fallback food are factors that likely contributed to the success of Rubondo chimpanzees in reverting to natural foraging behaviors after their release.     

Least limiting water range: A potential indicator of changes in near-surface soil physical quality after the conversion of Brazilian Savanna into pasture

The Brazilian savanna, or “Cerrado”, is an ecosystem that originally covered more than 200 Mha in Brazil. It is estimated that about 49.5 Mha in the Cerrado are now covered with cultivated pastures, which are responsible for half of Brazilian beef production. However, soil and pasture degradation represent a threat to this productive system and to the Cerrado ecosystem itself. Thus, the objective of this research was to evaluate the least limiting water range (LLWR) as an index of near-surface soil physical quality after conversion of Brazilian savanna to continuous and short-duration grazing systems. Three sites were evaluated: native Cerrado (NC), continuous grazing (CG), and short-duration grazing (SG). Thirty soil cores (5 cm height, 5 cm diameter) were collected at each site, and used for soil bulk density, soil water retention curve, and soil penetration resistance curve determinations. The results were used for quantification of LLWR and critical bulk density (D_bc), in which LLWR equals zero. The near-surface soil physical quality, as evaluated by the LLWR, was most restrictive for potential root growth in SG. In CG, potential restriction was moderate; however, the entire soil bulk density range was below the D_bc. In NC, potential restriction was minimum. The soil structural degradation process was primarily related to the increase in stocking rates in the grazing systems. The LLWR proved to be a useful indicator of Cerrado soil physical quality, being sensitive to alterations in near-surface physical properties.     

Global warming, elevational ranges and the vulnerability of tropical biota

Tropical species with narrow elevational ranges may be thermally specialized and vulnerable to global warming. Local studies of distributions along elevational gradients reveal small-scale patterns but do not allow generalizations among geographic regions or taxa. We critically assessed data from 249 studies of species elevational distributions in the American, African, and Asia-Pacific tropics. Of these, 150 had sufficient data quality, sampling intensity, elevational range, and freedom from serious habitat disturbance to permit robust across-study comparisons. We found four main patterns: (1) species classified as elevational specialists (upper- or lower-zone specialists) are relatively more frequent in the American than Asia-Pacific tropics, with African tropics being intermediate; (2) elevational specialists are rare on islands, especially oceanic and smaller continental islands, largely due to a paucity of upper-zone specialists; (3) a relatively high proportion of plants and ectothermic vertebrates (amphibians and reptiles) are upper-zone specialists; and (4) relatively few endothermic vertebrates (birds and mammals) are upper-zone specialists. Understanding these broad-scale trends will help identify taxa and geographic regions vulnerable to global warming and highlight future research priorities.     

所有权概念探讨

在对比各国对所有权的不同界定的基础上,立足于我国国情,重新阐释了所有权的概念。     

新疆潜在蒸散分形特征与R/S趋势分析

[目的]分析新疆潜在蒸散的时间序列,判断时间序列的分形结构,对新疆潜在蒸散的变化趋势进行预测.[方法]应用Penman-Monteith模型计算了新疆53个气象台站1955～2008年的潜在蒸散量时间序列,并采用配分函数(统计矩)判定该时间序列的分形结构,再利用重标极差分析法(R/S)对新疆潜在蒸散变化趋势进行预测.[结果]配分函数τ(q)与q的线性关系非常明显,对于高阶q取值为10,20,…,100时也成立,依然有较好的线性关系.三个区域年平均潜在蒸散量时间序列存在明显的Hurst现象,Hurst指数分别为0.896 0、0.719 4、0.788 9.[结论]南疆区、北疆区、天山山区1955～2008年潜在蒸散时间序列是一个单分形结构.新疆潜在蒸散变化存在着持续性.其中,南疆区潜在蒸散的持续性最强,天山山区次之,北疆地区最弱.     

热带大西洋拟锥齿鲨资源动态和空间分布研究

拟锥齿鲨是热带大西洋金枪鱼延绳钓渔业中较为常见的兼捕物种,处于海洋生态系统的顶端,对维持海洋生态系统的稳定性和多样性起着非常重要的作用。根据我国金枪鱼渔业国家观察员2010—2015年在热带大西洋海域调查时收集的1 561尾拟锥齿鲨数据,对其资源动态和空间分布进行了初步分析,结果表明:在研究的海域内(6.33°S~17.43°N,18.25°W~42.03°W),拟锥齿鲨CPUE高的区域为5°N~10°N,20°W~30°W;2010—2015年CPUE呈现波动,整体有上升的趋势,但不显著;软骨鱼类占总渔获物的比例整体呈下降趋势;拟锥齿鲨兼捕数量占总渔获的5.8%,占兼捕软骨鱼类的22.5%;拟锥齿鲨在12月—3月的平均CPUE较高。拟锥齿鲨最大叉长组(叉长范围在85~90 cm)的个体多分布在5°N~7.5°N,27.5°W~37.5°W和5°N~0°,25°W~30°W这两个区域。拟锥齿鲨理论钩获深度范围为140~313 m,平均深度为221 m。1、2、3钩位(140~212 m)的上钩频率最大,占总上钩率的55.59%。10月至次年4月不同月份拟锥齿鲨的钩位分布没有显著性的差异。妊娠期拟锥齿鲨明显分布于较浅的水层。不同钩位拟锥齿鲨的摄食等级无显著性差异。