Is landscape sustainability a useful concept in a changing world?

The world is changing rapidly, challenging the sustainability of landscapes and the resources and ecosystem services they provide to people and to plants and animals. Changes in land use and climate will alter the structure and composition of landscapes, and landscape functions may also be disrupted if the changes drive systems past thresholds into novel, no-analog configurations. Although landscapes will persist in some form, it is unlikely that they will provide the same values to people or habitat for wildlife that are the focus of current sustainability efforts. Tradeoffs among services to people or resources for wildlife will be inevitable. For the concept of sustainability to be relevant under these conditions, we must ask, “Sustainability of what, for whom?” Landscapes cannot be all things to all people (or organisms). Decisions about how to balance competing needs and goals and set priorities requires an understanding of landscape structure, function, and change—the foundation elements of landscape ecology.     

Weather and land cover create a predictable “stress-scape” for a winter-adapted bird

Landscape Ecology - Variability in temperature and snow cover are characteristics of high-latitude environments that impose significant pressures on overwintering species. To cope with increased...     

小型西瓜早春高密度栽培技术a

小型西瓜肉质细嫩、皮薄、脆甜、风味佳,具有较高的经济价值,近年栽培面积呈逐年上升趋势。因小型西瓜的生育特性与普通西瓜有明显差异,在栽培上也有其特殊性,故要求栽培技术和条件较高。目前小型西瓜种植密度较低,一般每667m~2450～1500株,产量相对较低,为1500～2500kg。     

苹果MdRGL3a基因的功能分析

为进一步揭示苹果(Malus×domestica)中GA信号转导机制以及MdDELLAs的生理功能,以‘嘎拉’苹果为试材,克隆基因MdRGL3a(GenBank:DQ007887),并通过在拟南芥中过量表达,分析该基因的功能。qRT-PCR结果表明,MdRGL3a在苹果不同组织中都有表达,其中在花和果实中表达量较高。在拟南芥中异位表达MdRGL3a,表现为根长和下胚轴变短,种子萌发较慢,叶片变小,植株矮化。过表达MdRGL3a拟南芥植株对赤霉素介导的生长反应敏感性降低,证明MdRGL3a是GA信号途径中的一个负调控因子。     

高产线椒新品种长虹362a

正长虹362a是北京中农绿亨种子科技有限公司生产的一个线椒新品种,四川兴文县鲵源蔬果种植专业合作社从2008年开始引种试验,其表现十分突出,产量高、品质好、耐储运,深受农户和菜商的喜爱,现已成为当地主栽品种,种植面积达33.3 hm2。     

Recreation shapes a “landscape of fear” for a threatened forest bird species in Central Europe

Predators can create a “landscape of fear” that influences the spatial distribution of their prey. Understanding whether human activity similarly affects the distribution of species beyond habitat suitability is crucial but difficult to assess for conservation managers. Here, we assessed the effect of recreation and forestry activity on a threatened forest-dwelling umbrella species, the Capercaillie (Tetrao urogallus). We followed the citizen science approach on the landscape scale in the Bohemian Forest. We analyzed species data non-invasively collected through intensive fieldwork by volunteers and assessed human activity in the entire study area by analyzing expert questionnaires. The study area extends over 119,000 ha and harbors one of the largest relict populations of this grouse species in Central European low mountain ranges. Our statistical models revealed a negative impact of recreational activities on the intensity of habitat use of the birds within suitable habitats, thereby pointing toward a landscape of fear. The influence of forestry activity, in contrast, was not clear. In comparison to existing regional tourism impact studies, we were able to elevate the examination to the landscape scale. Our results underlined the relevance of recreation in limiting the species’ habitat on an entire landscape and allow us to conclude that habitat managers should set aside well-defined zones without recreational activities to preserve the refuge of this umbrella species.     

What size is a biologically relevant landscape?

The spatial extent at which landscape structure best predicts population response, called the scale of effect, varies across species. An ability to predict the scale of effect of a landscape using species traits would make landscape study design more efficient and would enable landscape managers to plan at the appropriate scale. We used an individual based simulation model to predict how species traits influence the scale of effect. Specifically, we tested the effects of dispersal distance, reproductive rate, and informed movement behavior on the radius at which percent habitat cover best predicts population abundance in a focal area. Scale of effect for species with random movement behavior was compared to scale of effect for species with three (cumulative) levels of information use during dispersal: habitat based settlement, conspecific density based settlement, and gap-avoidance during movement. Consistent with a common belief among researchers, dispersal distance had a strong, positive influence on scale of effect. A general guideline for empiricists is to expect the radius of a landscape to be 4?C9 times the median dispersal distance or 0.3?C0.5 times the maximum dispersal distance of a species. Informed dispersal led to greater increases in population size than did increased reproductive rate. Similarly, informed dispersal led to more strongly decreased scales of effect than did reproductive rate. Most notably, gap-avoidance resulted in scales that were 0.2?C0.5 times those of non-avoidant species. This is the first study to generate testable hypotheses concerning the mechanisms underlying the scale at which populations respond to the landscape.     

甜橙SWEET2a促进柑橘溃疡病菌侵染

柑橘溃疡病菌（Xanthomonas citri subsp. citri,Xcc）侵染感病种质冰糖橙叶片后，在侵染部位形成典型的火山口凸起症状，但在抗病种质枸橼C-05叶片侵染部位呈现逐渐褐色坏死，未形成溃疡病典型症状。基于前期冰糖橙和枸橼C-05叶片接种Xcc的转录组测序结果，分析鉴定的20个甜橙SWEET受Xcc诱导表达变化，结果显示SWEET2a和SWEET17d在冰糖橙中受Xcc诱导上调表达，SWEET12b在枸橼C-05中受Xcc诱导上调表达；实时荧光定量PCR验证，SWEET2a在冰糖橙叶片中受Xcc诱导高表达而在枸橼C-05叶片中表达变化不显著；SWEET2a在不同柑橘种质同源基因编码的氨基酸序列相似性为94.6%，其启动子顺式作用元件在冰糖橙和枸橼C-05中的种类和数量存在较大差异。冰糖橙和枸橼C-05叶片瞬时过表达结果显示，SWEET2a促进Xcc的繁殖，且拟南芥过表达转基因株系接种毒性菌Pst.DC3000(Pseudomonas syringae tomato DC3000)后，单位叶面积菌含量显著高于野生型。SWEET2a蛋白部分定位于质膜，表明SWEET2a...     

PlantDB – a versatile database for managing plant research

Background  

Research in plant science laboratories often involves usage of many different species, cultivars, ecotypes, mutants, alleles or transgenic lines. This creates a great challenge to keep track of the identity of experimental plants and stored samples or seeds.     

马铃薯抗晚疫病基因RB、R3a过表达及R3a特异性识别关键结构域的确定

 通过将马铃薯抗晚疫病基因RB、R3a编码区克隆到具有组成型CaMV35S强启动子的双元表达载体上,结合农杆菌介导的瞬时表达,分析过表达条件下RB-AvrB,R3a-Avr3a的特异性识别情况。并利用重叠延伸PCR实现R3a与同源序列I2GA1在卷曲螺旋（CC）、核酸结合位点（NBS）和富含亮氨酸重复序列（LRR）三个结构域的互换,根据过敏性反应（hypersensitive response,HR）是否被阻断分析各个结构域对特异性识别的影响,确定特异性识别的关键结构域。结果表明：CaMV35S启动子驱动的RB基因在表达量上较自身启动子有明显提高,使HR反应加快; R3a的表达量和特异性识别Avr3a诱导产生HR反应的速度在两者之间均无明显差别。另外,R3a与I2GA1在LRR区域序列发生交换后,识别Avr3a诱导产生HR反应的能力也发生了交换,即R3a特异性识别Avr3a的关键序列位于LRR结构域内。     

Construction of a Plasmid and a Standard Curve for Real-time Quantitative PCR of the Cold-induced Cor3 Gene from Volvariella volvacea

A plasmid containing target DNA and a standard curve for real-time quantitative PCR of the coldinduced Cor3 gene of Volvariella volvacea were constructed. These will provide the basis for further research on Cor3 gene expression at low temperature, and ultimately for assigning a role for the gene in the low temperature autolysis of V. volvacea.     

What multiscale environmental drivers can best be discriminated from a habitat index derived from a remotely sensed vegetation time series?

Understanding which environmental conditions are critical for species survival is a critical, ongoing question in ecology. These conditions can range from climate, at the broadest scale, through to elevation and other local landscape conditions, to fine scale landscape patterns of land cover and use. Remote sensing is an ideal technology to monitor and assess changes in these environmental conditions at a variety of spatial and temporal scales, with many studies focusing on the physiological state of vegetation derived from time series of satellite measurements. As vegetation occurs within specific climatic zones, over certain soil, terrain, and land cover types, it can be difficult to decipher the influence of the underlying role of climate, topography, soil, and land cover on the observed vegetation signal. In this article, we specifically addressed this problem by asking the question: what is the relative impact and importance of these different scales of environmental drivers on the temporal and spatial patterns observed on a habitat index derived from remotely sensed data? To find the solution, we utilized a SPOT VEGETATION-normalized difference vegetation index time series of Europe to create a remote-sensing-derived habitat index, which incorporates aspects of productivity, seasonality, and cover. We then compared the observed temporal and spatial variations in the index to a pan-Europe terrestrial classification system, which explicitly incorporates variations in climate, terrain, soil parent material, land cover, and use. Results indicated that the most accurate level of discrimination from the habitat index was at the broadest level of the hierarchy, climate, while the poorest degree of discrimination was associated with elevation. In terms of similarity on the index across time and space, we found that arable and forest cover classes were more similar across elevation and parent materials than across other land cover types within them. Analyzing the remote-sensing index, at multiple scales, provides significant insights into the drivers of satellite-derived greenness indices, as well as highlights the benefit and cautions associated with linking satellite-derived indirect indicators to species distribution modeling and biodiversity.     

Responses of leaf photosynthesis and plant growth to altered source–sink balance in a Japanese and a Dutch tomato cultivar

We investigated the effects of altered source/sink ratio by leaf or fruit pruning on leaf photosynthetic characteristics and whole-plant growth of ‘Momotaro York’, a Japanese cultivar, and ‘Dundee’, a Dutch cultivar and verified a hypothesis for sink-limitation of plant growth proposed by Tanaka and Fujita (1974). Plants were grown hydroponically with a high-wire system in a greenhouse for 11 weeks. Light-saturated photosynthesis of young, fully expanded leaves measured at atmospheric CO₂ partial pressure of 37 Pa and at an intercellular CO₂ partial pressure of 20 Pa was not influenced by alteration of source/sink ratio for either cultivar. Although soluble sugars were accumulated in leaves under high source/sink conditions, the amount of ribulose-1,5-bisphosphate carboxylase/oxygenase, a rate-limiting factor for CO₂-limited photosynthesis, was not affected by the altered source–sink balance. Net assimilation rate of a whole plant increased with decreasing source/sink ratio, but this can be accounted for by the changes in light interception per unit leaf area, without taking the source–sink relationship into consideration. It was concluded that the altered source/sink ratio did not change leaf photosynthetic capacity and the sink-limitation hypothesis cannot be applied to either cultivar under the conditions of the present study.     

Stand-replacing patches within a ‘mixed severity’ fire regime: quantitative characterization using recent fires in a long-established natural fire area

The complexity inherent in variable, or mixed-severity fire regimes makes quantitative characterization of important fire regime attributes (e.g., proportion of landscape burned at different severities, size and distribution of stand-replacing patches) difficult. As a result, there is ambiguity associated with the term ‘mixed-severity’. We address this ambiguity through spatial analysis of two recent wildland fires in upper elevation mixed-conifer forests that occurred in an area with over 30 years of relatively freely-burning natural fires. We take advantage of robust estimates of fire severity and detailed spatial datasets to investigate patterns and controls on stand-replacing patches within these fires. Stand-replacing patches made up 15% of the total burned area between the two fires, which consisted of many small patches (<4 ha) and few large patches (>60 ha). Smaller stand-replacing patches were generally associated with shrub-dominated (Arctostaphylos spp. and Ceanothus spp.) and pine-dominated vegetation types, while larger stand-replacing patches tended to occur in more shade-tolerant, fir-dominated types. Additionally, in shrub-dominated types stand-replacing patches were often constrained to the underlying patch of vegetation, which for the shrub type were smaller across the two fire areas than vegetation patches for all other dominant vegetation types. For white and red fir forest types we found little evidence of vegetation patch constraint on the extent of stand-replacing patches. The patch dynamics we identified can be used to inform management strategies for landscapes in similar forest types.     

龙眼pri-miR319a编码短肽活性的研究

为研究龙眼miRNA编码短肽(miRNA encode regulatory peptide,miPEP)的潜在活性,以miR319为对象,从7个龙眼品种中克隆得到pri-miR319a序列并预测其潜在编码miPEP,并通过遗传转化和人工合成miPEP的方法验证miPEP319a的活性。结果显示,7个龙眼品种中pri-miR319a序列存在10个核苷酸的差异,并具有3个潜在ORF可以编码miPEP,其中1个核苷酸突变位点导致miPEP319a氨基酸序列的改变。进一步通过原位转化法获得转化miPEP的过表达载体及相应突变表达载体的龙眼幼芽,并结合人工合成miPEP319处理龙眼胚性愈伤组织,进一步验证龙眼miPEP的生物学活性。结果显示,pri-miR319a编码的3个潜在miPEP仅miPEP319a-2具有生物学活性并促进下游mi R319a的表达。最后采用烟草叶片的瞬时转化法验证龙眼miPEP319a在烟草当中的活性及对miR319a的影响。结果表明龙眼miPEP319a具有物种特异性,在烟草叶片中miR319a的表达模式无差异。该研究结果提示龙眼pri-miR319序列在不同品种中具有多态性,且其编码的3个潜在miPEP仅mi PEP319a-2具有生物学活性,并具有物种特异性,同时也暗示龙眼miPEP319a-2可以参与到龙眼的生长发育过程中。     

甘菊ClCOL5a基因的克隆与表达分析

以甘菊为试材,采用基因克隆及生物信息学方法,克隆了甘菊ClCOL5a基因并对其进行生物信息学分析及表达分析。结果表明:该基因共编码347个氨基酸,编码序列中含有2个保守的B-Box结构域和1个CCT结构域,属于CO家族的I类基因。NCBI Blastp分析与进化树分析均显示,该基因编码产物与拟南芥CO家族中AtCOL5相似性最高,故将该基因命名为ClCOL5a。实时定量分析显示,ClCOL5a为组成型表达,且在叶中表达量最高。在花芽膨大的过程中,ClCOL5a基因的表达逐渐升高,并在露色时达到最大值,之后逐渐降低,表明ClCOL5a在甘菊开花过程中可能发挥着重要功能。     

番茄耐裂果基因Cr3a的精细定位

以栽培番茄(Solanum lycopersicum)‘1052’为遗传背景的潘那利番茄(S.pennellii)‘LA0716’的渐渗系‘14h616’含有‘LA0716’第3染色体上长度为2.66Mb的片段,该片段含有番茄耐裂果基因Cr3a。以‘14h616’和‘1052’为亲本构建了番茄耐裂果基因Cr3a的亚渐渗系群体,以亚渐渗系群体F5代中易裂果和含有耐裂果基因Cr3a的耐裂果为材料制作石蜡切片,测量果实含水量。结果表明易裂果番茄与含Cr3a耐裂果番茄果皮角质层厚度和表皮细胞层数均无显著差异;但绿熟期易裂番茄果实含水量显著高于含Cr3a耐裂番茄。亚渐渗系群体遗传分析并结合表型鉴定结果表明,番茄耐裂性对易裂性为不完全显性关系,基因Cr3a的遗传贡献率是27.41%;将Cr3a定位于分子标记3-ZY75和3-ZY43约349kb范围内,在该区段内检测到47个候选基因。利用分子标记对以耐裂材料‘182h640’为母本、易裂材料‘182h680’为父本构建的F2群体及200份遗传背景不同的高代材料进行验证,符合性较好,选择准确度可达96%。本研究的结果为Cr3a的图位克隆和番茄耐裂果分子改良打下了坚实的基础。     

Is coppice a potential for urban forestry? The social perspective

After years of decline and neglect, low woodland types based on coppice management experience renewed interest. Substantial research has demonstrated the potentials of coppice for biomass production and for nature conservation, and coppices are increasingly being suggested for urban situations. Yet, our understanding of the more social aspects of coppice woodlands in modern urban situations is limited. Against this background, this contribution classifies coppice management systems as a basis for identification of social aspects of coppices and their potential use in contemporary urban forestry. Based on this classification, the social perspectives and potential niches for urban coppices are discussed, while lines of research are suggested which will support the development of a thorough and up-to-date knowledge base, against which the social merits of urban coppice woodlands can be critically evaluated.     

桃乙烯应答因子PpERF1a的克隆与功能分析

以‘丰光’油桃嫩梢组织为试材，克隆了1个ERF家族基因并命名为PpERF1a（ppa018178m）。该基因全长为600 bp，编码199个氨基酸，含有1 个典型的AP2 结构域。亚细胞定位结果显示PpERF1a定位于细胞膜和细胞核。在拟南芥中超量表达PpERF1a，共获得15个阳性转基因株系。与对照相比，转基因植株出现发育不良的表型，其中6株持续长出莲座叶，但不抽薹；6株能够抽薹开花，但不结实且生长势明显弱于对照；3株能够开花结实，但种子产量极低。这些结果表明PpERF1a在转基因拟南芥中具有调控生长发育的功能，为后期在桃中开展PpERF1a的功能研究提供了有益的启示。