Soil CO2 evolution from Korean pine virgin forest at Changbai Mountain

The soil CO₂ evolution rate was measured in a virgin Korean pine forest. The results in June showed that the lowest value of evolution rate was 220 mg/(m²·h) and appeared at 6:00 a.m. The highest value was 460 mg/(m²·h) at 18:00. The rates of CO₂ evolution were related with soil temperature. On the basis of the constructed regression equation and the monthly average values of temperature, the magnitude of CO₂ evolution from Korean pine forest soil was 10.4 t/hm² during a growing season. This project was funded by the Opened Research Station of Changbai Mountain Forest Ecosystem, Chinese Academy of Sciences. Responsible editor: Zhu Hong     

三大区域村庄类型分布的刻画：历史移民解读

中国农村存在巨大的区域差异,从社会结构上看,可以分为华南宗族团结型地区、中部原子化分散型地区和华北小亲族分裂型地区三大区域.通过数据挖掘和分析,发现我国出生性别比的分布极具规律性,显示出区域上的差异.结合中国南方方言形成及南方宗族型文化发育的共同历史移民根源,笔者将南方方言分布图与出生性别比地图及三大区域划分进行比较研究,具体分析了三者间高度关联性的共同历史移民根源.     

从中全新世古森林探讨生物多样性变化

本文从历史植物地理学的角度、根据川西南山地冕宁县沉黄沼泽地层中发掘出中全新世以来保存完好的大量古森林遗迹资料，通过多学科综合性研究证实，中全新世“沉黄古森林”距今约７０００多年，是由４４科、５５属、７３种森林植物组成，以铁杉为主要建群种，林内混生有多种常绿和落叶针阔叶树种。从该森林的演变和种类组成变化得知，在距今４５００年～２８００年间，铁杉和阔叶树种数量减少，云南松数量增加，杉木已从森林中消失；距今２８００年后铁杉进一步减少，云南松显著增加，黄杉、华山松、油杉、桦木、木荷、桤木逐渐从森林中消失；距今２０００年左右，铁杉和雪松从森林中消失。目前该地区森林已演变成云南松林或松栎混交林。森林生态环境演变大致分为４个阶段：（１）温暖多雨阶段（距今７０００年以前）；（２）温暖湿润阶段（距今７０００年～４５００年）；（３）温暖潮润阶段（距今４５００年～２８００年）；（４）温暖干燥阶段（距今２８００年以来）。由上可见，沉黄中全新世古森林及生态环境的演变，提供了这一森林生态系统在时间和空间上物种多样性变化的实例。     

Methyl Jasmonate Counteract UV-B Stress in Barley Seedlings

The role of exogenously applied phytohormone methyl jasmonate (MeJA) in counteracting the ultraviolet B (UV‐B) stress in barley seedlings was investigated. Barley seedlings (Hordeum vulgare L., cv. Alfa) 4 days old were supplied with 5 × 10^?5 m MeJA through the roots for 3 days and then exposed for 2 days for 5 h per day to UV‐B (312 nm, biological effectiveness of UV‐B radiation 28.8 kJ m^?2day^?1). The rate of ¹⁴CO₂ fixation, PSI and PSII activities and chlorophyll content decreased, but flavonoids, H₂O₂, malondialdehyde, proline and UV‐B induced compounds increased after UV‐B treatment. The rate of photosynthetic oxygen evolution was more strongly inhibited by UV‐B‐irradiation than PSI and PSII efficiency. MeJA itself increased the content of free proline, which acts as a stress protector due to its radical scavenging ability. Increased superoxide dismutase, catalase and peroxidase (POX) activities in the leaves and in the roots and the POX isoforms induction revealed the MeJA involvement in plant tolerance to oxidative stress caused by UV‐B irradiation. It was shown that pre‐treatment with MeJA counteracted UV‐B stress. Therefore, it was suggested that MeJA could acts as a mediator in plant defense responses to UV‐B irradiation by enhancing the activity of antioxidant system and free radical scavenging capability of plant cells.     

Analysis of Genetic Diversity in Barley Cultivars Reveals Incongruence Between S-SAP,SNP and Pedigree Data

Accurate assessment of genetic similarity is important for plant breeding, germplasm enhancement and conservation of plant genetic resources. A comparative analysis of genome diversity among a group of six-rowed spring barley (Hordeum vulgare L.) cultivars was carried out using sequence-specific amplified polymorphism (S-SAP) and single nucleotide polymorphism (SNP), with the results compared to the kinship coefficients derived from the pedigree data. Mean pair-wise GS values were estimated to be 0.0957 ± 0.144 (Kinship), 0.491 ± 0.189 (SNPs), and 0.602 ± 0.098 (S-SAPs). S-SAP and SNP-based genetic similarity (GS) values were normally distributed but kinship values had a non-normal and skewed distribution. Pair-wise correlation of GS values were lowest for the S-SAP and the SNP matrices (r =; 0.040, p<0.230) and highest for the SNP and pedigree matrices (r =; 0.240, p < 0.001). Analysis of molecular variance (AMOVA) attributed about 90.4% of observed variation to the cultivars within each of the malting and feed groups. Variance component between malting and feed groups was 6.6% for both SNP and S-SAP data suggesting lack of a significant genetic differentiation along this agronomic division. The remaining 3% of variation was attributed to genetic diversity within cultivars. Although both DNA-based marker systems were able to differentiate all barley cultivars, significant difference were observed in the pattern of genetic relationships obtained by the two marker systems and the pedigree data.     

Cloning, characterization and expression of cDNA containing major histocompatibility complex class I, IIα and IIβ genes of Japanese flounder Paralichthys olivaceus

ABSTRACT:   The nucleotide sequences of Japanese flounder Paralichthys olivaceus , major histocompatibility complex (MHC) cDNA, classical MHC class Iα, non-classical MHC class Iβ, MHC class IIα and IIβ, were determined. The domain structures and antigen binding motifs of vertebrate MHC are conserved in the Japanese flounder MHC. A phylogenetic analysis supports the classification of these genes into class I and class II MHC. Classical MHC class Iα was ubiquitously expressed, whereas the non-classical MHC class Iβ was expressed mainly in lymphoid organs, gills, intestine and stomach. The MHC classes IIα and IIβ were also ubiquitously expressed.     

Logging pattern and landscape changes over the last century at the boreal and deciduous forest transition in Eastern Canada

Forestry practices associated with the industrial era (since ~1900) have altered the natural disturbance regimes and greatly impacted the world’s forests. We quantified twentieth century logging patterns and regional scale consequences in three sub-boreal forest landscapes of Eastern Canada (117,000, 49,400 and 92,300 ha), comparing forestry maps depicting age and forest cover types for early industrial (1930) and present-day (2000) conditions. Results were similar for the three landscapes, indicating large-scale forest change during the twentieth century. In 1930, previous logging activities had been concentrated in the lowlands and along the main hydrographical network, as compared to a more even distribution over the landscapes in 2000, reflecting a decreasing influence of the environmental constraints on forest harvesting. In 1930, old-aged forests (>100 years) accounted for more than 75% of the unlogged areas of the three landscapes, as compared to less than 15% for the present-day conditions. Logging practices have thus inverted the stand age distribution of the landscapes that are currently dominated by young and regenerating stands. The 1930 forest cover types showed a clear relationship with elevation, with conifers located in the lowlands and mixed and deciduous stands restricted to the upper slopes. Between 1930 and 2000, 58–64% of the conifer areas transformed to mixed and deciduous forests, such that no clear altitudinal relationships remained in 2000. We conclude that twentieth century logging practices have strongly altered the preindustrial vegetation patterns in our study area, to the point that ecosystem-based management strategies should be developed to restore conifer dominance, altitudinal gradients, as well as the irregular structure inspired from old forest stands.     

Isolation,Identification, 16S rRNA Gene Sequencing and Genetic Evolution Analysis of Aeromonas aeruginosa from Duck

【Objective】 The experiment was aimed to study the pathogenic bacteria of acute death of ducklings in a duck farm in Henan province and its phylogenetic status.【Method】 The liver and spleen of dead ducks in the diseased duck farm were collected.The bacterial morphology, Gram-staining, biochemical characteristics, sequence analysis of 16S rRNA gene, drug sensitivity test and pathogenicity test were carried out.【Results】 The isolated bacteria grew on blood agar medium with smooth, convex, milky white and α-hemolytic Gram-positive cocci.Biochemical test results showed that the isolated bacteria were positive for maltose, sucrose, raffinose, nitrate reduction reaction, MP-VP test, urea, lysine decarboxylase, ornithine decarboxylase and aescin, and negative for xylose, lactose, glucose, sorbitol, hydrogen sulfide, citrate, peptone, mannitol, phenylalanine and methyl red.The results of 16S rRNA gene sequencing and BLAST comparison results showed that the 16S rRNA gene sequence of the isolated strain was 94.8%-99.9% similar to that of Aerococcus viridans published on NCBI, and the similarity with strains Mnlv1, Mnlv2 and W66 was the highest, up to 99.9%.The similarity with strain GXBl-1 was the lowest, which was 94.8%.Phylogenetic tree analysis showed that the isolated bacteria belonged to the same genus and group on the same branch as strains of Aerococcus viridans FL09, 15MS and Mnlv2 etc., and had the closest genetic relationship with FL09.The results of drug sensitivity showed that the isolated strain was sensitive to fosfomycin, ampicillin and amoxicillin, moderately sensitive to penicillin, neomycin and amikacin, it was resistant to rifampicin, neomycin, bacitracin, erythromycin and enrofloxacin.The results of pathogenicity test showed that the strain was lethal and increased with the increase of inoculation concentration.【Conclusion】 This study determined that the pathogen causing the acute death of ducklings in a duck farm in Henan province was Aerococcus viridans, which provided a reference basis for clinical diagnosis and treatment of the diseases caused by this bacteria.     

猪多杀性巴氏杆菌的分离鉴定及oppA基因遗传进化分析

【目的】了解福建省猪场猪多杀性巴氏杆菌（Pasteurella multocida,Pm）的流行及oppA基因遗传进化情况。【方法】本研究采用细菌分离培养、生化试验、16S rRNA PCR扩增测序、PCR荚膜分型、oppA基因克隆及相似性分析、动物回归试验等方法对分离菌株进行鉴定和分析。【结果】本研究共分离到10株菌,分离菌在血平板上形成淡灰白色、湿润光滑、奶油露珠状菌落;分离菌株能酵解蔗糖、果糖、麦芽糖和甘露醇,不能分解葡萄糖、枸橼酸盐、乳糖、硫化氢等,与多杀性巴氏杆菌生化特性基本一致;分离菌株16S rRNA序列与GenBank中登录的多杀性巴氏杆菌相似性达99.9%以上,10株分离菌均为多杀性巴氏杆菌;PCR荚膜分型显示,6株分离菌为荚膜A型,4株为荚膜D型;基于oppA基因的遗传进化树显示,10株分离菌均位于同一分支内;动物回归试验结果显示,在24 h内攻毒小鼠死亡率较高（21/30）,分离菌有较强的致病力。【结论】福建省猪场猪多杀性巴氏杆菌流行菌株的荚膜血清型主要是A和D型,且大部分菌株都来源于共同的祖先,本研究结果丰富了猪多杀性巴氏杆菌的流行病学资料,并为该病的防控奠定基础。     

球毛壳菌对樟子松的侵染规律研究

榆林风沙区樟子松枯死主要发生在10—15年生幼龄林上，7月上旬至8月下旬为感病高峰期，翌年4月中旬至5月中旬为死亡高峰期。病菌孢子在整个生长季均能放散与传播，降雨节律及降雨量直接影响孢子的扩散与数量。人工接种发现：病菌的侵入期主要在6月中旬至8月中旬，潜育期半个月，侵入途径是伤口，病株感病部位及枯死枝是病原菌的越冬场所，密度高，植被盖度大的林分感病重。