N、P、K异质含量拟南芥试管苗的表型适应特性

以模式种拟南芥为试验材料,有别于自然环境下生长的拟南芥,借助于组织培养方法利用均匀设计对培养基中KNO3、NH4NO3、KH2PO4设置处理,探讨试管环境下拟南芥生长发育特性及对营养离子需求吸收特点,结果显示拟南芥本性地通过加强莲座叶与茎生叶的功能以增加生殖生长期的分枝数与苔高;生殖生长期影响试管苗茎生叶数、苔高的离子种类增多,离子的交互作用更加复杂。通过分析模式植物对N、P、K异质含量培养基的表型适应特点可推论同一植物在不同时期使用单一培养基是不合理的。

交替使用消毒剂?不一定能有效抑制微生物抗体的产生

抗性可以分为很多不同的种类,每一种生物体都有一种对有害物天生的、特殊的抗性。不同的微生物对不利环境的适应能力也有所不同。在食品、化妆品、服务等行业,消毒剂常被用来预防控制传染病及防止由细菌引起的食品腐烂。在医药领域和家畜饲养领域中,经常可以看到关于＂微生物会对抗生素产生抗性＂的报道。那么在食品相关领域,微生物是否也会对消毒剂产生抗性？部分文献中已经提到某些微生物会对消毒剂产生抗性。

Effects of environment and genotype-by-environment interaction on phenotype of Rorippa elata(Brassicaceae),an endemic alpine plant in the Hengduan mountains

Global climate change poses a severe threat to mountain biodiversity.Phenotypic plasticity and local adaptation are two common strategies for alpine plant to cope with such change.They may facilitate organismal adaptation to contrasting environments,depending on the influences of the environment or genotype or their interacted effects.In this study,we use an endemic alpine plant(Rorippa elata)in the Hengduan mountains(HDM)to unravel its phenotypic basis of adaptation strategy and evaluate the relative contributions of environment and genotype to its phenotype.We transplanted 37 genotypes of R.elata into two common gardens across low and high elevations(2800 vs.3800 m)during 2021-2022.Nine fitness-related traits were measured,including flowering probability and glucosinolates(GS)content.We estimated the environmental or genotypic contributions to the phenotype and identified the main environmental components.Our results revealed that both environment and genotype-by-environment interactions contributed to the phenotypes of R.elata.Latitudinal heterogeneity was identified as a key factor that explained 24%of the total phenotypic variation.In particular,genotypes of the northern HDM showed significantly higher plasticity in flowering probability than those of the southern HDM.Furthermore,within the southern HDM,GS content indicated local adaptation to herbivory stresses for R.elata genotypes along elevations.In conclusion,our results suggest that R.elata may have adapted to the alpine environment through species-level plasticity or regional-level local adaptation.These processes were shaped by either complex topography or interactions between genotype and mountain environments.Our study provides empirical evidence on the adaptation of alpine plants.

Competition and the evolution of imperfect mimicry

Mimicry is widely used to exemplify natural selection＇s power in promoting adaptation. Nonetheless, it has become increasingly clear that mimicry is frequently imprecise. Indeed, the phenotypic match is often poor between mimics and models in many Batesian mimicry complexes and among co-mimics in many Mtillerian mimicry complexes. Here, we consider whether such imperfect mimicry represents an evolutionary compromise between predator-mediated selection favoring mimetic conver- gence on the one hand and competitively mediated selection favoring divergence on the other hand. Specifically, for mimicry to be effective, mimics and their models/co-mimics should occur together. Yet, co-occurring species that are phenotypically similar often compete for resources, successful reproduction, or both. As an adaptive response to minimize such costly interactions, in-teracting species may diverge phenotypically through an evolutionary process known as character displacement. Such divergence between mimics and their models/co-mimics may thereby result in imperfect mimicry. We review the various ways in which character displacement could promote imprecise mimicry, describe the conditions under which this process may be especially likely to produce imperfect mimicry, examine a possible case study, and discuss avenues for future research. Generally, character displacement may play an underappreciated role in fostering inexact mimicry .

Hormones and phenotypic plasticity： Implications for the evolution of integrated adaptive phenotypes

It is generally accepted that taxa exhibit genetic variation in phenotypic plasticity, but many questions remain unan- swered about how divergent plastic responses evolve under dissimilar ecological conditions. Hormones are signaling molecules that act as proximate mediators of phenotype expression by regulating a variety of cellular, physiological, and behavioral re- sponses. Hormones not only change cellular and physiological states but also influence gene expression directly or indirectly, thereby linking environmental conditions to phenotypic development. Studying how hormonal pathways respond to environ- mental variation and how those responses differ between individuals, populations, and species can expand our understanding of the evolution of phenotypic plasticity. Here, we explore the ways that the study of hormone signaling is providing new insights into the underlying proximate bases for individual, population or species variation in plasticity. Using several studies as exem- plars, we examine how a ＇norm of reaction＇ approach can be used in investigations of hormone-mediated plasticity to inform the following： 1） how environmental cues affect the component hormones, receptors and enzymes that comprise any endocrine sig- naling pathway, 2） how genetic and epigenetic variation in endocrine-associated genes can generate variation in plasticity among these diverse components, and 3） how phenotypes mediated by the same hormone can be coupled and decoupled via independent plastic responses of signaling components across target tissues. Future studies that apply approaches such as reaction norms and network modeling to questions concerning how hormones link environmental stimuli to ecologically-relevant phenotypic re- sponses should help unravel how phenotypic plasticity evolves

In nomen omen:the effect of flower distance on female reproductive success of the lax-flowered orchid Anacamptis laxiflora(Orchidaceae)

Aims In multiflowered species,the architecture of inflorescences is of primary importance in shaping plant attractiveness.The aim of this study was to disentangle the role of inflorescence traits in plant female reproductive success and pollination patterns along the inflorescence in the lax-flowered orchid Anacamptis laxiflora,a terrestrial species exploiting a deceptive pollination strategy.We also evaluated whether the relationship between inflorescence traits and female reproductive success was modified by the height of surrounding vegetation and/or by population density.Methods We delimited experimental plots in a natural population of A.laxiflora.We tallied the individuals within each plot and categorized low-density plots and high-density plots;then,in part of the plots we manually removed surrounding grass thus producing an equal number of plots with high grass and low grass.Within these plots,we recorded inflorescence traits and female reproductive success(i.e.the number of fruit and their position along the inflorescence).We analyzed these data using generalized linear mixed-effects models(GLMMs)and calculated selection gradients.Important Findings We found that all the investigated inflorescence traits influenced female reproductive success.In particular,our GLMMs showed that'average flower distance'was the best predictor for shaping reproductive success patterns.We detected significant positive selection on the investigated inflorescence traits,but these selective trends were strictly linked to both the height of the surrounding vegetation and the population density,suggesting a significant influence of local environmental context in shaping selective patterns.Female reproductive success was not linked to the position of flowers along the inflorescence,suggesting that pollinators visit flowers randomly along the inflorescence without a detectable preference for a specific part.This study highlights the importance of inflorescence traits in shaping female reproductive success of multiflowered deceptive orchids,and confirms a primary role for the environmental context in modifying pollinator-mediated selection patterns.

Inducible competitors and adaptive diversification

Identifying the causes of diversification is central to evolutionary biology. The ecological theory of adaptive diversi- fication holds that the evolution of phenotypic differences between populations and species--and the formation of new spe- cies-stems from divergent natural selection, often arising from competitive interactions. Although increasing evidence suggests that phenotypic plasticity can facilitate this process, it is not generally appreciated that competitively mediated selection often also provides ideal conditions for phenotypic plasticity to evolve in the first place. Here, we discuss how competition plays at least two key roles in adaptive diversification depending on its pattern. First, heterogenous competition initially generates heterogeneity in resource use that favors adaptive plasticity in the form of ＂inducible competitors＂. Second, once such competitively induced plas- ticity evolves, its capacity to rapidly generate phenotypic variation and expose phenotypes to alternate selective regimes allows populations to respond readily to selection favoring diversification, as may occur when competition generates steady diversifying selection that permanently drives the evolutionary divergence of populations that use different resources. Thus, competition plays two important roles in adaptive diversification---one well-known and the other only now emerging--mediated through its effect on the evolution ofphenotypic plasticity