北京水系中腐霉和疫腐霉种类调查

为研究北京地区水系中腐霉和疫腐霉种类分布,采用叶饵法从北京水系中诱集菌株,共分离到腐霉、疫腐霉182株,利用Single-strand conformation polymorphism (SSCP)进行分析,筛选出不同基因型的代表菌株,并依据形态学特征及ITS序列对这些菌株进行种类鉴定。结果共发现6个已知种和3个可能的新种,其中:湖滨疫腐霉Phytopythium litorale和果胶裂解腐霉Pythium pectinolyticum为国内新记录种;旋柄疫腐霉Pp.helicoides、异丝腐霉P.diclinum、簇囊腐霉P.torulosum和袋囊腐霉P.marsipium为北京地区新记录种。研究结果可为未来监测北京地区水系中病原菌的分布情况提供基础数据。     

Exploring tree diversity and stand structure of savanna woodlands in southeastern Sudan

Savanna woodlands in Sudan host great biodiversity, provide a plethora of ecosystem goods and services to local communities, and sustain numerous ecological functions. Although the importance of the Acacia trees in these areas is well known, up-to-date information about these woodlands' diversity is limited and changes in their woody vegetation composition, density, diversity and relative frequency are not monitored over time. This study explored tree diversity and stand stage structure in Nuara Reserved Forest, a typical savanna woodland ecosystem in southeastern Sudan. A total of 638 circular sample plots (1000 m² for each) were established using a systematic sampling grid method. The distance between plots was 200 m. In each plot, all living trees with diameter at breast height (DBH) ≥5.00 cm were identified and counted, and their DBH values were recorded. From these data, tree composition, diversity, density and stage structure were assessed. There were 12,259 individual trees representing four species (Acacia seyal, Balanites aegyptiaca, Acacia Senegal and Acacia mellifera) that belong to two families. The dominant species was Acacia seyal. Average tree density was 191 trees/hm² and the Shannon-Weiner index for trees diversity was 0.204. Overall, young trees comprised 86.30% of the forest. The state of tree richness and density in the study area was low compared to other similar environments in the region and around the world. We recommended adoption of a proper management system that includes monitoring of woody vegetation diversity in this forest, and management actions to enhance tree diversity and sustain ecosystem services to local communities. In addition to care for the dominant Acacia seyal stands, more attention and conservation should be devoted to reestablishing Acacia senegal and Acacia mellifera trees because of their high ecological and economic values for local communities.     

A new species of Malus in China,Malus shizongensis Liu sp. nov

Based on morphological, molecular biological, and molecular systematic studies, we describe here a new species of Malus from Yunnan, China. We compared the morphology of this new species, Malus shizongensis Liu sp. nov, with three Malus species, including M. hupehensis, M. baccata, and M. micromalus. Although the appearance of M. shizongensis was similar to these three species, it differed in height, branch color, branch hair, and flower color. To better identify the taxonomy of this new species, genome of M. shizongensis and that of seven Malus species, including M. prunifolia, M. sylvestris, M. sieversii, M. hupehensis, M. baccata, M. robusta, and M. micromalus were analyzed. A phylogenetic tree based on genome analysis indicated that M. shizongensis was close to M. hupehensis. Furthermore, M. shizongensis had its species-specific SNPs, and the number of species-specific SNPs was similar to that of three close species(M. hupehensis, M. baccata, and M. micromalus). Based on the above information, we named this new species as M. shizongensis Liu sp. nov.     

西双版纳南览河流域常见观赏蝶种及其寄主植物资源调查

西双版纳勐海县境内南览河流域具有良好的天然植被,蝴蝶种类繁多。为了开展重要观赏蝶种的人工繁育试验,2013—2018年对南览河中低海拔地带的常见观赏蝴蝶及其野生寄主植物资源开展了进一步的深入调查,结果表明,经过5年定点调查和沿线观察,在区域内发现兼具较高观赏价值及人工繁育潜力的蝶种46个;通过观察野外成虫的产卵活动,结合野外套袋及室内饲养幼虫,发现蝴蝶寄主植物38种,初步查明了相关蝶种的野生寄主植物资源。调查工作可为筛选出当地适生优良寄主植物、进一步开展相关蝶种的人工养殖试验提供参考。     

茂兰自然保护区森林景观格局变化分析

本文以2011年和2017的森林调查成果化数据为基础,依据不同优势树种组,采用景观格局指数法,从组成结构、斑块特征、景观异质性和空间分布4方面分析2011年和2017年茂兰自然保护区的森林景观格局及其变化。结果表明：林地面积增加了654.08 hm²；森林优势树种数量从15种增加至30种；景观面积(CA)最大的均为阔叶混交树种组,增加了1286.33hm²；斑块平均大小(MpS)最大的均为阔叶混交树种组,增加了471.80 hm²；面积加权的平均形状指数(AWMSI)和面积加权的平均分形指数(AWMPFD)最大值均为阔叶混交树种组；景观斑块边缘密度(ED)最大值均为阔叶混交树种组；阔叶混交树种组的平均最小距离(ENN)减少。从2011年2017年研究区的主要优势树种组阔叶混交树种组得以保护,这与人为干扰的减少有关。     

翁源青云山自然保护区维管束植物区系特征分析

青云山省级自然保护区位于韶关翁源县的东南部,本研究在查阅文献、历史标本的基础上,对本区进行全面踏查、标本采集并鉴定,从而进行植物物种多样性编目和区系分析。结果表明：青云山自然保护区有维管束植物1336种（含种下分类单位）,其中石松类和蕨类植物132种,隶属于62属24科,裸子植物6种,隶属于4属4科,被子植物1198种,隶属于588属148科;本区的表征科主要以樟科（Lauraceae）、壳斗科（Fagaceae）、冬青科（Aquifoliaceae）等为主。植物区系地理组成复杂,主要以热带、亚热带为主,且热带、亚热带的过渡性质明显。从中国特有种的分布情况来看,该地区与湖南南部、广西东北部、江西西南部联系较为紧密,体现了南岭山脉植物区系的一致性与整体性;珍稀濒危植物共计48种;植被具有中亚热带向南亚热带过渡的特征。青云山自然保护区植物物种丰富度高、植被类型多样,建议将园洞、青山口等珍稀濒危植物分布较集中的地区列为优先保护区域。     

Importance of mitochondrial calcium uniporter in high glucose-induced cardiac myocyte apoptosis

AIM: To investigate the role of mitochondrial calcium uniporter (MCU) in high glucose(HG)-induced apoptosis of cardiac myocytes. METHODS: Cardiac myocytes were exposed to normal glucose (5.5 mmol/L glucose+ 19.5 mmol/L mannitol), HG (25 mmol/L glucose), or HG combined with 5 μmol/L spermine for 72 h. Mitochondrial free Ca²⁺ concentration ([Ca²⁺]_m), MCU at mRNA and protein levels, pyruvate dehydrogenase (PDH) activity, mitochondrial membrane potential (Δψ_m), the levels of ATP and reactive oxygen species (ROS), and apoptosis were determined. RESULTS: The [Ca²⁺]_m, the mRNA and protein levels of MCU, PDH activity, ATP levels, and Δψ_m were reduced (P<0.05), while ROS content and the protein levels of caspase-9 and caspase-3 were increased in HG group (P<0.05). Adding 5 μmol/L spermine returned these parameters toward control levels (P<0.05). Moreover, apoptosis was reduced by adding spermine and HG treatment (P<0.05). CONCLUSION: HG-induced cardiac myocyte apoptosis may be associated with the decreased MCU expression and activity, abnormal mitochondrial Ca²⁺ handling, deviant mitochon-drial respiratory chain, and mitochondrial dysfunction.     

灰霉菌侵染对番茄幼苗活性氧积累及抗氧化酶活性的影响

为进一步分析活性氧和抗氧化防御系统在番茄抗病信号调控机制中的作用,为提高产量和品质提供科学依据,以4叶1心的番茄幼苗为试验材料,比较番茄幼苗受灰霉菌侵染后叶片O_2~-·以及抗氧化酶、内源褪黑素等的变化。结果表明:番茄幼苗接种灰霉菌后,随着时间的延长,幼苗叶片上病斑斑点逐渐增多,灰霉菌含量显著增多,叶色逐渐变浅,植株表现明显的发病症状;灰霉病菌侵染后番茄体内O_2~-·活性爆发,超氧化物歧化酶(SOD)和过氧化物酶(POD)活性下降,过氧化氢酶(CAT)和谷胱甘肽还原酶(GR)活性上升,褪黑素含量增加;上述变化都是番茄幼苗为了抵御灰霉菌的生物胁迫而发生的应激反应。综上,植物在遭受病原菌等生物胁迫时不能简单地推断SOD、CAT和POD等抗氧化酶活性一定升高,植物抵御病原菌侵染更多地依赖于抗性信号路径中信号物质的激活和积累。     

First evidence of spawning migration by goldfish (Carassius auratus); implications for control of a globally invasive species

Goldfish (Carassius auratus) was one of the first fishes to be domesticated and has been widely introduced across the globe, but is now considered one of the world's worst invasive aquatic species. Surprisingly, there is a dearth of information on its spatial and temporal movement patterns, which hampers the development of effective control programmes. We examined the movement patterns of an introduced population of C. auratus in a south‐western Australian river using passive acoustic telemetry. The study population had a high residency index within the array (i.e. proportion of all days at liberty that, on average, each fish was detected by a receiver) with fish being detected on 64% of days. The individuals were also reasonably mobile, travelling a mean of 0.30 km (linear river kilometres).day^‐1 within the array, and one fish moved 231.3 km over the 365‐day study period (including 5.4 km in a 24 hr period). Importantly, C. auratus displayed significant seasonal movement patterns including a clear shift in habitats during its breeding period with most mature individuals being detected in an off‐channel wetland during that time. The results of this study strongly suggest that C. auratus undertook a spawning migration into a lentic habitat. These results have important implications for developing control programmes for the species, such as targeting connections to off‐channel lentic systems during its breeding period.     

Experimental investigation on the transport of different fish species in a jet fish pump

A jet fish pump with a throat of ø60 mm was designed to study its performance in the transport of different fish species and the physiological changes in fish thereafter. Experiments were conducted to investigate the fish transport rate and energy required to transport each ton of fish when transporting Carassius auratus, commonly known as the Chinese goldfish, Megalobrama amblycephala, or Wuchang bream, and Ctenopharyngodon idella, the grass carp. Fish were examined for external injuries as well as for several important enzymes and hormones which are indicators of tissue injury and stress. The results showed that the transport rate for all three species of fish rose dramatically with an increase in the primary stream rate. In this experiment, the transport rates of C. auratus, M. amblycephala and C. idella reached 2357 ± 37.2 kg ∙ h⁻¹, 2888 ± 41.6 kg ∙ h⁻¹, and 2060 ± 40.2 kg ∙ h⁻¹, respectively. However, both injury rate and energy required to transport each ton of fish increased no matter whether the primary stream rate was too low or too high. Considering both transport rate and injury rate, the mean primary stream rate of 80 m³ ∙ h⁻¹ was determined to be the optimal operating condition in this experiment. Fish were stressed and most likely some of their organs were damaged. However, most physiological indexes almost fully recovered after several hours.