植物水淹适应与碳水化合物的相关性

水淹会对陆生植物存活造成本质影响, 特别是完全水淹对陆生植物的影响更为明显。水淹对陆生植物最为主要的影响是氧气不足, 这主要是由氧气在水中的扩散速率较低引起的。同时, 在水淹胁迫下植物对光和CO₂的获取都会受到限制。所有这些因素都将引起植物生物量减少, 最终导致受淹植物死亡。碳水化合物是植物的能量来源, 与植物在水淹胁迫下存活与否有着密切联系。植物水淹适应性与碳水化合物的相关性主要体现在两大方面: 在生理形态层面, 植物通过伸长生长或抑制伸长生长、地上和地下部分碳水化合物的分配比例不同来应对水淹胁迫; 在另一个层面, 植物通过改变激素、酶和基因的表达, 调整碳水化合物的代谢方式, 从而适应水淹环境。该文结合国内外研究现状, 通过对植物在水淹胁迫下生理形态、激素、酶及基因表达诸方面的变化来认识水淹耐受性与碳水化合物的关系, 并就今后的研究方向提出几点建议。     

森林植物耐荫性及其形态和生理适应性研究进展

耐荫性是植物在低光环境下的生存和生长能力,对森林植物群落演替起重要作用,植物对遮荫的适应机制已成为生态学的研究热点.本文综述了森林植物的耐荫性及其在形态和生理方面的适应性,分析了森林植物在生长性状、生物量分配、树冠结构、叶片形态生理、叶片解剖结构、光合参数、碳水化合物分配、水分和养分的利用等方面对遮荫产生的可塑性响应,最后对目前研究存在的问题进行了分析,展望了未来的研究内容和方向.     

Geographic origin and past climatic experience influence the response to late spring frost in four common grass species in central Europe

Late spring frost events can affect vegetation. The response of grassland species, however, is generally unknown. We explore the late‐frost sensitivity of four common European grass species and investigate whether these species exhibit local adaptations to late frost on a continental scale and whether past climatic experience influences late frost sensitivity. Ecotypes of Arrhenatherum elatius, Alopecurus pratensis, Festuca pratensis, and Holcus lanatus from Spain, Italy, Bulgaria, Hungary, Sweden and Germany were exposed to late frost after drought and warming manipulations in the preceding growing season in a common garden experiment. Late frost reduced the productivity of the grasses on average by 20%. Ecotypes differed in their late‐frost sensitivity in three of the four species and local adaptations to late frost were identified. Previous exposure to drought and warming caused differences in late‐frost sensitivity in some cases. The impact of late frost events may increase in a warmer world due to an earlier onset of growing and no change in timing of late frost events. The history of climatic exposure can alter the performance of plants, possibly through epigenetic mechanisms. Based on the complex response pattern observed, a maximization of genetic diversity is proposed as a promising adaptation strategy against climate change.     

Molecular regulatory mechanisms underlying the adaptability of polyploid plants

Polyploidization influences the genetic composition and gene expression of an organism. This multi-level genetic change allows the formation of new regulatory pathways leading to increased adaptability. Although both forms of polyploidization provide advantages, autopolyploids were long thought to have little impact on plant divergence compared to allopolyploids due to their formation through genome duplication only, rather than in combination with hybridization. Recent advances have begun to clarify the molecular regulatory mechanisms such as microRNAs, alternative splicing, RNA-binding proteins, histone modifications, chromatin remodelling, DNA methylation, and N⁶-methyladenosine (m6A) RNA methylation underlying the evolutionary success of polyploids. Such research is expanding our understanding of the evolutionary adaptability of polyploids and the regulatory pathways that allow adaptive plasticity in a variety of plant species. Herein we review the roles of individual molecular regulatory mechanisms and their potential synergistic pathways underlying plant evolution and adaptation. Notably, increasing interest in m6A methylation has provided a new component in potential mechanistic coordination that is still predominantly unexplored. Future research should attempt to identify and functionally characterize the evolutionary impact of both individual and synergistic pathways in polyploid plant species.     

三峡库区消落区几种两栖植物的适生性评价

根据三峡库区消落区的环境特征,两年间通过在库区消落区山地实验基地的种植及实地淹没试验,对几种备选用于生态修复的两栖植物进行适生性评价筛选研究.结果表明:狗牙根(Cynodon dactylon)、野地瓜藤(Ficus tikoua)、尼泊尔蓼(Polygonum nepalense )、水花生( Alternanthera philoxeroides)、百喜草(Paspalum Notatum )、香根草(Vetiveria zizanioides)、苏丹草(Sorghum sudanense)在100～150d的低水位出露期内均可完成生长、发育成熟过程,可作为消落区生态恢复的备选物种.其中,苏丹草可作为速生物种,能迅速恢复水位下降后消落区的植被覆盖率;复合群落在生长期间比单一种群提前5～10d完成对地表的覆盖,群落的稳定性、耐淤积性及抗干扰性较强,次年的萌发也更好,有利于构建稳定的生态系统;狗牙根、尼泊尔蓼和野地瓜藤根系生长良好,其中狗牙根在一个生长季内根系最长可达75cm, 有利于消落区控制水土流失;在自然水淹最深为15m,淹没时间6d的情况下,复合群落组植物、尼泊尔蓼、野地瓜藤、狗牙根和苏丹草的植物均能短期耐水淹和淤泥,水花生则是在水淹较深处能够生长良好;180d水下1.0～1.5m的连续淹水实验结果表明,狗牙根和野地瓜藤的耐淹性较强,经过长达半年的淹水过程能够成活,并在次年自然萌发;同时5～25m的深部淹水实验表明,随着深度增加,狗牙根的落叶率逐步提高,在180d的淹没后能够成活,并在次年自然萌发,可作为构建消落区生态系统的两栖植物物种.     

Nitrogen uptake in the Weddell Sea during late winter and spring

Summary Uptake rates of ammonium, nitrate and urea were measured during the EPOS leg 1 cruise to the Weddell Sea in October–November 1988 using the isotope ¹⁵N. Nitrate was the most important nitrogen source both for ice algae (f-ratio 0.88) and for phytoplankton in the water column (f-ratio 0.85). Indications of a gradual decrease in % new production with time were found in the outer marginal ice zone. Nitrogen uptake rates in ice algae from the sub-ice assemblage were light-limited at in situ irradiances. Significant regeneration of ammonium was found in ice algal samples only.Data presented here were collected during the European Polarstern Study (EPOS) sponsored by the European Science Foundation     

石山稀有濒危植物迁地保护适应性研究(简报)

报道了青檀、桂林紫薇、东京桐、掌叶木、任木、小花异裂菊和海南椴 7种石山稀有濒危植物迁移到酸性红壤上的表现     

A Pinus cembra L. tree-ring record for late spring to late summer temperature in the Rhaetian Alps,Italy

Ongoing climate change strongly affects high-elevation environments in the European Alps, influencing the cryosphere and the biosphere and causing widespread retreat of glaciers and changes in biomes. Nevertheless, high-elevation areas often lack long meteorological series, and global datasets cannot represent local variations well. Thus, proxy data, such as tree rings, provide information on past climatic variations from these remote sites. Although maximum latewood density (MXD) chronologies provide better temperature information than those based on tree-ring width (TRW), MXD series from the European Alps are lacking. To derive high-quality temperature information for the Rhaetian Alps, Pinus cembra L. trees sampled at approximately 2000 m a.s.l. were used to build one MXD chronology spanning from 1647 to 2015. The MXD data were significantly and highly correlated with seasonal May-September mean temperatures. The MXD chronology showed a generally positive trend since the middle of the 19^th century, interrupted by short phases of climatic deterioration in the beginning of the 20^th century and in the 1970s, conforming with the temperature trends. Our results underline the potential for using Pinus cembra L. MXD to reconstruct mean temperature variations, especially during the onset and latter part of the growing season, providing additional information on parts of the growing season not inferred from TRW. Future studies on MXD for this species will increase the availability of temporal and spatial data, allowing detailed climate reconstructions.     

Avian botulism during late autumn and early spring in Saskatchewan

Two outbreaks of botulism in central Saskatchewan in which mortality of waterfowl continued into late autumn and then recurred in the same marshes the following spring are described. Small numbers of birds were involved in each instance. Dabbling ducks (predominantly mallards, Anas platyrhynchos and pintails, Anas acuta) and American coots, Fulica americana were affected most commonly in autumn, whereas only diving ducks (predominantly lesser scaup, Aythya affinis) were found to be involved in spring. Live maggots present in carcasses despite sub-freezing temperatures were the probable source of intoxication in the autumn; the source of toxin in the spring was not determined.     

木本植物对喀斯特石质生境岩石形态结构的适应性

为弄清植物对喀斯特岩石形态结构的适应性,选择3种岩石类型及7种木本群落为研究对象,基于分形、空间句法理论研究岩石结构面孔裂隙形态结构及其与群落特征的关系。结果表明:石灰岩结构面孔裂隙间隙度大、白云岩居中、白云质砂岩小,分维数则反之;白云质砂岩结构面孔裂隙整合度、控制值、密度值大,白云岩居中,石灰岩小;白云岩生境下群落物种多样性及优势种碳、氮含量高、白云质砂岩次之、石灰岩低;分形与空间句法指数间呈显著相关关系,两者能较好的揭示岩石形态结构;总体上3种岩性生境下物种多样性及优势种碳、氮含量与岩石结构面孔裂隙分形及空间句法指数具较强相关关系;大致相同的环境下白云岩形态结构适宜植物生长、白云质砂岩次之、石灰岩差;研究岩石形态结构对喀斯特植被恢复具有重要意义。     

烟粉虱对不同寄主植物的选择性和适应性测试

为了明确在田间烟粉虱Bemisia tabaci(Gennadius)对不同寄主植物选择性和适应性,本实验在室内用Y型嗅觉仪测定了烟粉虱对13种寄主植物的选择性,随后对田间随机排列种植的这13种寄主植物依照测试结果由强到弱依次拔除(拔除次序为茄子、番茄、黄瓜、辣椒、棉花、茼麻、西葫芦、油菜、花菜、小青菜、莲花白、胡萝卜和苦瓜),每次拔除间隔时间为5 d,结果显示:田间第一次调查的结果与室内选择性测试结果一致;随着最适宜寄主的拔除,烟粉虱成虫数量在与其引诱力相近的一种或几种寄主上的略有增加,而其它植物上却没有大的变化,这表明随着最适宜寄主的拔除,烟粉虱成虫会重新分布,但趋向分布于引诱力相对较强的寄主植物;随着寄主植物的拔除,烟粉虱卵、若虫和蛹在引诱力较强的植株上均有所增加;但西葫芦拔除之后其余植株上烟粉虱卵、若虫和蛹的数量没有明显变化;小青菜拔除后,其余植株上烟粉虱卵、若虫和蛹的数量又有所增加。这表明随着最佳寄主的拔除,烟粉虱会趋向选择于引诱力相对较强的寄主植物产卵,当烟粉虱从嗜好性强的植物转移到嗜好性弱的植物时,产卵适应会滞后于取食适应。但整个实验过程中苦瓜上的烟粉虱上成虫、卵、若虫和蛹的数量均变化不大,苦瓜上的成虫应属偶然分布其上,烟粉虱成虫并不取食苦瓜,苦瓜对烟粉虱有趋避作用。本实验模拟田间种植模式,因此实验结果对田间种植具有指导意义。     

小麦倒春寒研究现状与进展

由于全球气候变暖,近年来小麦低温灾害事件频发,尤其是拔节-孕穗期的倒春寒灾害已成为制约小麦产量和品质的重要因素之一.本文综述了小麦倒春寒灾害的发生特点(鉴定与分级、时空特征),倒春寒对小麦生理特性(叶片、茎秆、穗部、根系)和产量、质量的影响,总结了抗倒春寒小麦育种、倒春寒危害的分子生物学机制及灾害的监测预警与风险评估等...     

Nitrogen redistribution from the roots in post-anthesis plants of spring wheat

The aim of this study was to investigate post-anthesis N redistribution from the roots to other organs in the wheat plant. Two cultivars of spring wheat (Triticum aestivum L.) Sport and WL were grown to maturity in culture solution with stepwise-decreasing N supply and ¹⁵N before sampling. The N concentration of dry weight in the roots decreased from anthesis to full maturity. At maturity the root N concentration was 5.5 mg g⁻¹ dry weight for Sport and 4.9 mg g⁻¹ dry weight for WL, while the main shoot N concentration was 2.1 mg g⁻¹ dry weight for Sport and 2.2 mg g⁻¹ dry weight for WL. The roots were a major sink for N taken up post-anthesis and contained the main proportion of the ¹⁵N during the whole post-anthesis period. The N redistributed from the roots contributed 24.3% of the total N amount in the grains at maturity in cv Sport and 8.7% in cv WL. For cv Sport, 46.3% of the root N amount was redistributed to other parts of the plant and for WL 25.4%. The tiller grains were supplied with N from the ¹⁵N applied post-anthesis to a higher degree than the main shoot grains. The transport capability was maintained until 12 days after complete yellowness. We concluded that wheat has a great ability to redistribute nitrogen from the root system to the grains.     

Palaeobiogeography of late cretaceous belemnites of Europe

A North Temperate Realm, characterized by Belemnitellidae Pavlov, and a South Temperate Realm, characterized by Dimitobelidae WHITEHOUSE, existed throughout the Late Cretaceous, while Tethyan belemnites belonging to Belemnopseidae Naef existed only in the Cenomanian and disappeared afterwards. The North Temperate Realm may be subdivided into North European and North American Provinces. The latter province includes Greenland, Canada, the Western Interior Region of North America, and the Atlantic and Gulf coasts of North America. The belemnites from the North American Province, consisting of populations of the generaActinocamax Miller andBelemnitella d’Orbigny, are closely related to the belemnites of the North European Province and appear to have migrated from this province to North America via Greenland and Arctic Canada. The North European Province extends from Ireland to the Ural Mountains. Belemnites from this province belong to the following genera:Neohibolites Stolley,Parahibolites Stolley,Belemnocamax Crick,Actinocamax Miller,Belemnellocamax Naidin,Gonioteuthis Bayle,Belemnitella d’Orbigny,Belemnella Nowak, andFusiteuthis Kongiel. Two subprovinces within the North European Province have been recognized: the Central European and Central Russian Subprovinces. These subprovinces are well-defined in the late Coniacian-Early Campanian and are characterized by theGonioteuthis stock andBelemnitella stock, respectively. The two subprovinces are less distinct in other periods of the Late Cretaceous and may disappear completely.     

Towards mapping the late Quaternary vegetation change of Europe

The number of well-dated pollen diagrams in Europe has increased considerably over the last 30 years and many of them have been submitted to the European Pollen Database (EPD). This allows for the construction of increasingly precise maps of Holocene vegetation change across the continent. Chronological information in the EPD has been expressed in uncalibrated radiocarbon years, and most chronologies to date are based on this time scale. Here we present new chronologies for most of the datasets stored in the EPD based on calibrated radiocarbon years. Age information associated with pollen diagrams is often derived from the pollen stratigraphy itself or from other sedimentological information. We reviewed these chronological tie points and assigned uncertainties to them. The steps taken to generate the new chronologies are described and the rationale for a new classification system for age uncertainties is introduced. The resulting chronologies are fit for most continental-scale questions. They may not provide the best age model for particular sites, but may be viewed as general purpose chronologies. Taxonomic particularities of the data stored in the EPD are explained. An example is given of how the database can be queried to select samples with appropriate age control as well as the suitable taxonomic level to answer a specific research question.     

A review of invertebrates and seed-bearing plants as food for farmland birds in Europe

Dietary information was reviewed for 22 bird species typically found in farmland areas across Europe using 100 references from the UK and other European countries for which quantitative data were presented. The number of studies and degree of taxonomic resolution available varied considerably between the species and, for some, dietary information was only available prior to agricultural intensification and may be unrepresentative of current feeding habits. Consequently, some caution is required in interpreting the results because of the different methods of data collection between the studies and the biases in analytical techniques for prey detectability. Food availability was rarely quantified in the study areas, and diet may have reflected availability or preference. Plant families and invertebrate orders were ranked in their importance separately for adult diet in the breeding and nonbreeding seasons and for chicks. The most important plant families overall were Poaceae, Polygonaceae, Caryophyllaceae, Cruciferae, Compositae, Chenopodiaceae and Labiatae, although the last two were unimportant for chicks. A number of key species were also identified. Similarities in dietary preferences were observed among Fringillidae (finches) and members of the Columbidae (doves and pigeons). Fringillidae and Carduelis cannabina (linnet) were associated with plants that occur in seminatural habitats, while Emberiza citrinella (yellowhammer), Phasianidae (partridges) and Columbidae were shown to be more closely associated with plants of agricultural environments. The most important invertebrate orders overall were Coleoptera adults, Hemiptera adults, Arachnida, Lepidoptera larvae/pupae, Diptera adults, Lepidoptera adults, Diptera larvae/pupae and Hymenoptera adults. During the nonbreeding season, a smaller number of invertebrate taxa were important. For adults in the breeding season and for chicks, there were 10 families of invertebrate that were important for four or more bird species (Aphididae, Carabidae, Chrysomelidae, Curculionidae, Elateridae, Formicidae, Scarabeidae, Staphylinidae, Tenthredinidae and Tipulidae). In the nonbreeding season, Curculionidae and Lumbricidae were important in the diet of three species. A few species exhibited a narrow diet range, selecting invertebrates from only one or two families. Similarities in dietary composition were observed among closely related bird species, while that of chicks and adults sometimes differed.     

Epigenetic variability in plants: Heritability,adaptability, evolutionary significance

DNA methylation is the most stable epigenetic modification with a well studied maintenance mechanism in the mitotically dividing cell generations. The plant DNA is methylated at sites of three types, CG, CHG and CHH. The methylation mechanisms of these sites are different and involve functional activity of various DNA methyltransferases and their accessory factors, that largely define the genome locus specificity of methylation. The genome methylation pattern, DNA methylome, in plants is inheritable not only in the dividing cell generations but also to a considerable extent in generations of the whole plants. A great number of spontaneous epimutations, both natural and experimental ones, are known, that have discernible phenotypic manifestations and are stably inheritable in the plant generations as Mendelian traits. A fundamental distinction of such epimutations from classical mutations is their reversibility. The higher plants epigenome is much more flexible compared with their genome. The single-nucleotide epimutation frequency is hundredfolds higher than the mutation frequency. This variability is probably a main source of the plant phenotypic plasticity, that enables them to adapt to changing environment on the time scales too short for adaptive mutations to occur. A dramatic increase in the plant population epigenetic variability on a practically unchanged genetic context is observed when the essential environmental factors are rapidly changing. Being flexible enough for such adaptive changes, on the other hand, epigenome is stable enough for these adaptive variations to be inheritable between the plant generations. Obviously, the epigenetic variations, that enable plants to adapt to the fast changing environmental factors, serve as material for natural selection and other evolutionary processes on the respective time scales. A still another aspect of evolutionary significance is a capability of epigenetic mechanisms to induce transient bursts of genetic variability by transposon mobilization.     

Research project: A history of health in Europe from the late Paleolithic era to the present

This article briefly describes a large, multidisciplinary research project that combines skeletal data in Europe over the past 10,000 years with information from sources in history, archaeology, geography and climate history to measure and analyze important aspects of human health. Over this era human health was significantly affected by climate change, the rise of settled agriculture, urbanization, new technologies, global exploration and colonization, and industrialization.     

Regional behaviour among late Neanderthal groups in Western Europe: A comparative assessment of late Middle Palaeolithic bifacial tool variability

Population dynamics between and within Pleistocene groups are vital to understanding wider behavioural processes like social transmission and cultural variation. The late Middle Palaeolithic (MIS 5d-3, ca. 115,000–35,000 BP [years before present]) permits a novel, data-driven assessment of these concepts through a unique record: bifacial tools made by classic Neanderthals. Previously, studies of late Middle Palaeolithic bifacial tools were hampered by a convoluted plethora of competing terms, types and regional entities. This paper presents a large-scale intercomparison of this tool type, and bridges typo-technological and spatio-temporal data from across Western Europe (Britain, Belgium, the Netherlands, France and Germany).