Adaptive differentiation in floral traits in the presence of high gene flow in scarlet gilia (Ipomopsis aggregata)

Plant–pollinator interactions are thought to be major drivers of floral trait diversity. However, the relative importance of divergent pollinator‐mediated selection vs. neutral processes in floral character evolution has rarely been explored. We tested for adaptive floral trait evolution by comparing differentiation at neutral genetic loci to differentiation at quantitative floral traits in a putative Ipomopsis aggregata hybrid zone. Typical I. aggregata subsp. candida displays slender white tubular flowers that are typical of flowers pollinated by hawkmoths, and subsp. collina displays robust red tubular flowers typical of flowers pollinated by hummingbirds; yet, hybrid flower morphs are abundant across the East Slope of the Colorado Rockies. We estimated genetic differentiation (F_ST) for nuclear and chloroplast microsatellite loci and used a half‐sib design to calculate quantitative trait divergence (Q_ST) from collection sites across the morphological hybrid zone. We found little evidence for population structure and estimated mean F_ST to be 0.032. Q_ST values for several floral traits including corolla tube length and width, colour, and nectar volume were large and significantly greater than mean F_ST. We performed multivariate comparisons of neutral loci to genetic correlations within and between populations and found a strong signal for divergent selection, suggesting that specific combinations of floral display and reward traits may be the targets of selection. Our results show little support for historical subspecies categories, yet floral traits are more diverged than expected due to drift alone. Non‐neutral divergence for multivariate quantitative traits suggests that selection by pollinators is maintaining a correlation between display and reward traits.     

Mapping ‘hydroscapes’ along the iso‐ to anisohydric continuum of stomatal regulation of plant water status

The concept of iso‐ vs. anisohydry has been used to describe the stringency of stomatal regulation of plant water potential (ψ). However, metrics that accurately and consistently quantify species’ operating ranges along a continuum of iso‐ to anisohydry have been elusive. Additionally, most approaches to quantifying iso/anisohydry require labour‐intensive measurements during prolonged drought. We evaluated new and previously developed metrics of stringency of stomatal regulation of ψ during soil drying in eight woody species and determined whether easily‐determined leaf pressure–volume traits could serve as proxies for their degree of iso‐ vs. anisohydry. Two metrics of stringency of stomatal control of ψ, (1) a ‘hydroscape’ incorporating the landscape of ψ over which stomata control ψ, and (2) the slope of the daily range of ψ as pre‐dawn ψ declined, were strongly correlated with each other and with the leaf osmotic potential at full and zero turgor derived from pressure–volume curves.     

Fluctuating asymmetry: A tool for impact assessment on fish populations in a tropical polluted bay,Brazil

Fluctuating asymmetry (FA), which can be defined as random morphologic changes on bilateral symmetry plan of paired morphometric and meristic characters in response of environmental disturbances, is an alternative tool to traditional methods of environmental health assessment that has an interesting potential to appraise the state of adaptation of a population before that acute contaminations affect the whole community or ecosystem. This study aimed to assess the occurrence of FA in three morphometric and three meristic characters of the Corocoro grunt Orthopristis ruber (Cuvier, 1830), and compare the deviations in bilateral symmetry of this reef-associated and omnivorous in Guanabara Bay (Brazil), the venue for various outdoor aquatic sports during the 2016 Olympic Games. Five indexes of FA were tested over the six characters of 66 O. ruber, which were caught during the dry and wet seasons of 2011 and at three areas Guanabara Bay of different environmental characteristics. In addition to validate the existence of FA for O. ruber, our findings revealed significant deviations in the bilateral symmetry according to the FA indexes and fish characters. Together with the FA1 index, the number of gill rakers and the number of rays of the pectoral fin provided the best methodological approach to address the levels of FA in O. ruber as a response to environmental stressors in each region. The levels of FA in O. ruber was significantly lower in the Urca region (less impacted) than for individuals caught near the Paquetá Island and Rio-Niterói Bridge sites (more degraded). Partial Redundancy Analysis also shows that the fish characters are affected in different ways by environmental stressors, but especially in response to the levels of dissolved oxygen and, secondarily, to water transparency, and that Paquetá Island is apparently less impacted than the site near the Rio-Niterói Bridge. Our results confirm the potential of FA to be used as a tool to detect environmental effects on a reef-associated fish species in a tropical polluted bay, but further studies are necessary to validate our findings for other species and ecosystems.     

The mean and variability of a floral trait have opposing effects on fitness traits

Background and Aims Floral traits are essential for ensuring successful pollination and reproduction in flowering plants. In particular, style and anther positions are key for pollination accuracy and efficiency. Variation in these traits among individuals has been well studied, but less is known about variation within flowers and plants and its effect on pollination and reproductive success.Methods Style deflexion is responsible for herkogamy and important for pollen deposition in Passiflora incarnata. The degree of deflexion may vary among stigmas within flowers as well as among flowers. We measured the variability of style deflexion at both the flower and the plant level. The fitness consequences of the mean and variation of style deflexion were then evaluated under natural pollination by determining their relationship to pollen deposition, seed production and average seed weight using structural equation modelling. In addition, the relationship between style deflexion and self-pollen deposition was estimated in a greenhouse experiment.Key Results We found greater variation in style deflexion within flowers and plants than among plants. Variation of style deflexion at the flower and plant level was positively correlated, suggesting that variability in style deflexion may be a distinct trait in P. incarnata. Lower deflexion and reduced variation in that deflexion increased pollen deposition, which in turn increased seed number. However, lower styles also increased self-pollen deposition. In contrast, higher deflexion and greater variability of that deflexion increased variation in pollen deposition, which resulted in heavier seeds.Conclusions Variability of style deflexion and therefore stigma placement, independent from the mean, appears to be a property of individual P. incarnata plants. The mean and variability of style deflexion in P. incarnata affected seed number and seed weight in contrasting ways, through the quantity and potentially quality of pollen deposition. This antagonistic selection via different fitness components may maintain diverse style phenotypes.     

绿盲蝽中枢神经系统的解剖结构

【目的】阐述绿盲蝽Apolygus lucorum中枢神经系统的组成,辨识各组成部分的神经节解剖结构及其形态,计算中枢神经系统各神经节结构体积大小、解析其空间分布关系以及连接模式。【方法】采用免疫组织化学方法,使用突触蛋白抗体对绿盲蝽中枢神经系统神经髓进行染色标记,利用共聚焦激光扫描显微镜获取中枢神经系统各结构数码图像,使用三维图像分析软件对绿盲蝽中枢神经系统进行分析,并构建三维模型。【结果】绿盲蝽中枢神经系统从前往后分别由脑神经节、咽下神经节、前胸神经节和后部神经节组成。脑、咽下神经节和前胸神经节3个神经节融合在一块,形成脑-咽下神经节-前胸神经节复合体,并通过长的神经连索与后部神经节相连,从外观上看似由2个大的神经节构成,这种神经节愈合形式尚未在昆虫中发现过。前胸神经节与后部神经节分离,二者由长的神经连索连接起来。除前胸神经节由单独的神经原节构成外,其他3个神经节又由多个神经原节融合而成。脑包括前脑、中脑和后脑3部分。咽下神经节包括上颚神经节、下颚神经节和下唇神经节。后部神经节包括中胸、后胸和腹部神经节3部分。【结论】明确了绿盲蝽中枢神经系统的神经节构成,发现了绿盲蝽中枢神经系统各神经节的高度融合特性。该项研究结果为研究绿盲蝽中枢神经系统的发育、重塑和系统演化奠定了形态学基础,为研究中枢神经元形态、分布以及其对昆虫生理和行为的功能调控机制提供了结构框架。     

Associations of the Novel Polymorphisms of Periostin and Platelet-Derived Growth Factor Receptor-Like Genes with Egg Production Traits in Local Chinese Dagu Hens

The periostin (POSTN) and platelet-derived growth factor receptor-like (PDGFRL) genes are implicated in regulation of hen ovarian development. In the present study, these genes were explored as possible molecular markers associated with egg production, egg weight and body weight in Chinese Dagu hens. Samples were analyzed using the PCR-single strand conformation polymorphism (PCR-SSCP) method, followed by sequencing analysis, and three novel single nucleotide polymorphisms (SNPs) were identified within the candidate genes. Among them, an A/T transversion at base position 2727 in intron 2 of POSTN gene was found to be polymorphic and named SNP A2727T; and two transitions, G/A at position 6761 and A/G at base 6839 in exon 2 of PDGFRL gene were detected and named SNPs G6761A and A6839G, respectively. For the SNP A2727T, a total of 360 Dagu hens were classified as AA and AB genotypes, allele A was found present at a higher frequency. Moreover, the AA genotype was significantly correlated with higher hen-housed egg production (HHEP) at 43, 57, and 66 weeks (wks) of age and with a higher egg weight (EW) at 30 wks (P < 0.05). For the two linked SNPs (G6761A and A6839G) in the PDGFRL fragment, the hens were typed into TT, TC and CC genotypes, with the T allele shown to be dominant. The TT genotype was correlated with higher HHEP at 57 and 66 wks of age; genotype CC associated with the highest body weight and EW at 30 and 43 wks (P < 0.05), while it was correlated with the lowest HHEP at 57 and 66 wks of age (P < 0.05). Furthermore, five haplotypes were reconstructed based on these SNPs, with the AATT haplotype associated with the highest HHEP at 43 to 66 wks of age and higher EW at 30 wks (P < 0.05). Collectively, these SNPs identified in this study might be used as a potential molecular marker favorable to genetic improvement of egg productivity in chicken breeding.     

Mycorrhizas influence functional traits of two tallgrass prairie species

Over the past decade, functional traits that influence plant performance and thus, population, community, and ecosystem biology have garnered increasing attention. Generally lacking, however, has been consideration of how ubiquitous arbuscular mycorrhizas influence plant allometric and stoichiometric functional traits. We assessed how plant dependence on and responsiveness to mycorrhizas influence plant functional traits of a warm‐season, C4 grass, Andropogon gerardii Vitman, and the contrasting, cool‐season, C3 grass, Elymus canadensis L. We grew both host species with and without inoculation with mycorrhizal fungi, across a broad gradient of soil phosphorus availabilities. Both host species were facultatively mycotrophic, able to grow without mycorrhizas at high soil phosphorus availability. A. gerardii was most dependent upon mycorrhizas and E. canadensis was weakly dependent, but highly responsive to mycorrhizas. The high dependence of A. gerardii on mycorrhizas resulted in higher tissue P and N concentrations of inoculated than noninoculated plants. When not inoculated, E. canadensis was able to take up both P and N in similar amounts to inoculated plants because of its weak dependence on mycorrhizas for nutrient uptake and its pronounced ability to change root‐to‐shoot ratios. Unlike other highly dependent species, A. gerardii had a high root‐to‐shoot ratio and was able to suppress colonization by mycorrhizal fungi at high soil fertilities. E. canadensis, however, was unable to suppress colonization and had a lower root‐to shoot ratio than A. gerardii. The mycorrhiza‐related functional traits of both host species likely influence their performance in nature: both species attained the maximum responsiveness from mycorrhizas at soil phosphorus availabilities similar to those of tallgrass prairies. Dependence upon mycorrhizas affects performance in the absence of mycorrhizas. Responsiveness to mycorrhizal fungi is also a function of the environment and can be influenced by both mycorrhizal fungus species and soil fertility.     

多花黑麦草品种DUS测试数量性状分级分析

对多花黑麦草(Lolium multiflorum Lam.)7个品种进行了不同时期30个数量性状指标的测定,利用数量性状对多花黑麦草性状进行了概率分级的研究,并进行了相关性分析。结果表明,30个数量性状变异范围在7.55%~40.65%之间,变异系数最大的是分蘖数,最小的是千粒重。根据各数量性状的K-S检验及χ2检验,发现仅少部分性状不符合χ2分布;最终将28个数量性状分为5个等级,另外将抽穗期(春化后)和分蘖数分为3个等级。多花黑麦草的30个数量性状之间相关性分析结果表明株高与生长习性、小穗数与小穗密度、上部节间长与节间数呈极显著负相关,花序长与小穗密度呈极显著正相关。研究结果为多花黑麦草品种的鉴定评价、品种选育及数量性状的分级提供了理论依据。