搜索结果：American journal of botany

Lower respiratory infections (LRIs) remain the world's leading infectious cause of death. This analysis from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2023 provides global, regional, and national estimates of LRI incidence, mortality, and disability-adjusted life-years (DALYs), with attribution to 26 pathogens, including 11 newly modelled pathogens, across 204 countries and territories from 1990 to 2023. With new data and revised modelling techniques, these estimates serve as an update and expansion to GBD 2021. Through these estimates, we also aimed to assess progress towards the 2025 Global Action Plan for the Prevention and Control of Pneumonia and Diarrhoea (GAPPD) target for pneumonia mortality in children younger than 5 years. Mortality from LRIs, defined as physician-diagnosed pneumonia or bronchiolitis, was estimated using the Cause of Death Ensemble model with data from vital registration, verbal autopsy, surveillance, and minimally invasive tissue sampling. The Bayesian meta-regression tool DisMod-MR 2.1 was used to model overall morbidity due to LRIs. DALYs were calculated as the sum of years of life lost (YLLs) and years lived with disability (YLDs) for all locations, years, age groups, and sexes. We modelled pathogen-specific case-fatality ratios (CFRs) for each age group and location using splined binomial regression to create internally consistent estimates of incidence and mortality proportions attributable to viral, fungal, parasitic, and bacterial pathogens. Progress was assessed towards the GAPPD target of less than three deaths from pneumonia per 1000 livebirths, which is roughly equivalent to a mortality rate of less than 60 deaths per 100 000 children younger than 5 years. In 2023, LRIs were responsible for 2·50 million (95% uncertainty interval [UI] 2·24-2·81) deaths and 98·7 million (87·7-112) DALYs, with children younger than 5 years and adults aged 70 years and older carrying the highest burden. LRI mortality in children younger than 5 years fell by 33·4% (10·4-47·4) since 2010, with a global mortality rate of 94·8 (75·6-116·4) per 100 000 person-years in 2023. Among adults aged 70 years and older, the burden remained substantial with only marginal declines since 2010. A mortality rate of less than 60 deaths per 100 000 for children younger than 5 years was met by 129 of the 204 modelled countries in 2023. At a super-regional level, sub-Saharan Africa had an aggregate mortality rate in children younger than 5 years (hereafter referred to as under-5 mortality rate) furthest from the GAPPD target. Streptococcus pneumoniae continued to account for the largest number of LRI deaths globally (634 000 [95% UI 565 000-721 000] deaths or 25·3% [24·5-26·1] of all LRI deaths), followed by Staphylococcus aureus (271 000 [243 000-298 000] deaths or 10·9% [10·3-11·3]), and Klebsiella pneumoniae (228 000 [204 000-261 000] deaths or 9·1% [8·8-9·5]). Among pathogens newly modelled in this study, non-tuberculous mycobacteria (responsible for 177 000 [95% UI 155 000-201 000] deaths) and Aspergillus spp (responsible for 67 800 [59 900-75 900] deaths) emerged as important contributors. Altogether, the 11 newly modelled pathogens accounted for approximately 22% of LRI deaths. This comprehensive analysis underscores both the gains achieved through vaccination and the challenges that remain in controlling the LRI burden globally. Furthermore, it demonstrates persistent disparities in disease burden, with the highest mortality rates concentrated in countries in sub-Saharan Africa. Globally, as well as in these high-burden locations, the under-5 LRI mortality rate remains well above the GAPPD target. Progress towards this target requires equitable access to vaccines and preventive therapies-including newer interventions such as respiratory syncytial virus monoclonal antibodies-and health systems capable of early diagnosis and treatment. Expanding surveillance of emerging pathogens, strengthening adult immunisation programmes, and combating vaccine hesitancy are also crucial. As the global population ages, the dual challenge of sustaining gains in child survival while addressing the rising vulnerability in older adults will shape future pneumonia control strategies. Gates Foundation.

Calcium oxalate biomineralization in plants is phylogenetically widespread and morphologically diverse, but the function of these inorganic crystals is an area of active debate. The variety of environmental conditions that produce the crystals, as well as the inconsistent evidence that they provide antiherbivore defense across plant and herbivore species, suggests that different crystal morphologies might have different functions. Using Vitis riparia, or riverbank grape, we experimentally investigated the environmental influence of excess calcium and simulated herbivory on the formation of calcium oxalate druse and raphide crystals in leaves. We also investigated the putative defensive function of these crystals by using a no-choice herbivore bioassay manipulating herbivore diet composition to test for impacts of crystal shape on herbivore growth, both on its own and with plant chemistry. We found that the addition of calcium to soil increased the density of both raphide and druse crystals in V. riparia leaves. Contrary to expectations, the herbivory treatment decreased the density of raphides in leaves, and V. riparia-derived crystals did not impact weight gain, time to pupation, or survival of moth larvae. Our multifaceted test of the formation and function of calcium oxalate crystals in riverbank grape demonstrates that an abiotic factor (i.e., soil calcium) is a relatively stronger determinant of crystal production and that, contrary to hundreds of years of speculation on their function, these crystals do not seem to mediate plant-insect herbivory in all plant taxa. Instead, the alternative hypothesis of calcium regulation was supported by our experimental evidence.

Orchids have many pollination strategies, from highly species-specific mutualisms with insects to deceit pollination, including sexual deception. The family also has the most leafless, parasitic species (mycoheterotrophs) of any plant family. The occurrence of two types of deception simultaneously in individuals of a single species previously has been suggested to be highly improbable. We studied Corallorhiza striata in the field, documenting the behavior of pollinators on the plants. We compared structural features of C. striata flowers to those of other species in the genus and tested for the presence of nectar. We also examined over 6000 iNaturalist photo records of C. striata to expand our pollinator search. The only pollinators for which we found clear evidence were males of the ichneumonid wasp Pimpla pedalis, which visited the nectarless flowers and exhibited mating-type behavior. The floral structure of C. striata, especially with respect to the labellum, is distinct from that of bee- and fly-pollinated species of Corallorhiza. We demonstrated that wasps were attracted to flowers in the absence of visual cues. Corallorhiza striata is the first example of a pseudocopulatory orchid from North America, and Corallorhiza is only the second genus known to deceive an ichneumonid. It is trophically and reproductively deceptive in the same life stage. Four other fully mycoheterotrophic species and three partial mycoheterotrophs also are known to engage in both deceptions indicating that, although rare, simultaneous deception can be a successful strategy. Such parasitic plants provide opportunities to study unusual evolutionary and ecological phenomena.

Selective breeding over thousands of years has prioritized aboveground yield, with little regard for changes belowground. Roots underpin plant growth and resilience, but our knowledge of these critical structures lags behind that of aboveground structures. Accurately phenotyping root traits is labor-intensive, expensive, and often destructive. High-throughput, nondestructive methods are required to advance understanding of the fundamental biology of root systems and to integrate hard-to-measure root traits into breeding programs. We used American licorice (Glycyrrhiza lepidota Pursh.), a perennial legume with a rich ethnobotanical history, as a model to investigate root system phenotypes. We assessed root traits across multiple populations, analyzed relationships between above- and belowground phenotypes, and tested the use of multidimensional leaf traits, including spectral reflectance, in predicting root traits. Root traits of American licorice varied significantly across source populations. Root traits were strongly intercorrelated and each root trait correlated with an aboveground phenotype. Leaf spectral reflectance and elemental composition predicted belowground traits; however, interpretation of some trait-specific signals were complicated by isometric scaling between plant size and root traits. These findings demonstrate the use of high-dimensional leaf traits as a proxy for root traits, with potential applications for understanding foundational questions in plant biology and in breeding programs targeting belowground structures of perennial herbaceous species. Further optimization and larger studies are needed to improve predictive models.

The placement of Sladeniaceae s.l. (Sladenia and Ficalhoa) within Ericales has remained contentious, largely due to incongruent molecular signals between plastid and nuclear loci and lack of clear morphological synapomorphies supporting its circumscription. Resolving its phylogenetic position is essential for clarifying evolutionary relationships along the backbone of Ericales. We used genome-skimming and Angiosperms353 data to reconstruct plastid and nuclear phylogenies of Ericales, with comprehensive sampling of Sladeniaceae, Pentaphylacaceae, and allied families. Phytop and SNaQ analyses were applied to evaluate incomplete lineage sorting (ILS) and introgression. Divergence times were estimated using a relaxed-clock birth-death model in the IQ2MC pipeline, and paleo-niche modeling was used to infer the historical distribution of Sladenia. Plastid phylogenies support the inclusion of Ficalhoa within Sladeniaceae, whereas nuclear trees place Ficalhoa as sister to Pentaphylacaceae, indicating strong cytonuclear discordance. Our analyses revealed a high level of incomplete lineage sorting at the nodes subtending Sladenia, Ficalhoa, and Pentaphylacaceae (ILS-i = 84.8%), which may be explained by the rapid early diversification of core Ericales during the mid-Cretaceous (~110-105 million years ago). No evidence of introgression was detected between Ficalhoa and Sladenia. Our findings suggest that stochastic sorting of ancestral plastid polymorphisms during rapid diversification may be the primary cause of cytonuclear discordance in the placement of Ficalhoa, although ancient plastid capture cannot be ruled out. These results support the inclusion of Ficalhoa within Pentaphylacaceae and underscore the roles of rapid diversification and incomplete lineage sorting in shaping deep phylogenetic relationships in Ericales.

Shoot and root apical meristems (SAMs and RAMs, respectively) drive primary vascular plant growth, yet their 2-D profile geometries remain poorly quantified. Shoot and root apical meristems differ in evolutionary origin, cellular organization, and developmental context, prompting investigation into whether their shapes differ within and across angiosperms, gymnosperms, and representative seedless vascular plants. SAM and RAM profiles from 11 representative taxa were extracted from histological images. Six nonlinear equations (the catenary, parabolic, hybrid catenary-parabolic, performance, superparabolic, and superellipse equations) were fitted to normalized profile coordinates. Model performance was evaluated using the Akaike information criterion (AIC). The superparabolic equation provided the best fit for eight of 16 of the SAM and RAM profiles, as evidenced by the lowest AIC values, whereas the hybrid catenary-parabolic equation performed best for five profiles. These two equations outperformed the other four, though no single model was universally superior across all profiles. Although meristem shapes differed, SAM and RAM geometries showed no consistent differences across the three plant groupings. Both the superparabolic and hybrid catenary-parabolic equations provide robust descriptions of SAM and RAM profiles, perhaps reflecting a convergence in apical meristem geometry across otherwise divergent vascular plant lineages. This quantitative approach offers a potential tool for comparing meristem geometry and shape that can be extended to the study of nonvascular plants to increase our understanding of plant form, evolution, and meristem functionality.

Ancestors of oceanic insular floras arrived via long-distance dispersal as a function of the geographic location, climatic habitats, and geologic age of the island. As a result, these floras comprise a mix of lineages, derived from distinct colonization events with different continental and insular origins. We assembled distributional data for native plant species in four Macaronesian archipelagoes (Azores, Madeira, Canary Islands, and Cabo Verde). Drawing from phylogenetic studies, we assigned each endemic species to a lineage. Five regions represent where the closest relatives of these lineages occur: American, temperate northern Europe, Mediterranean, Saharan, and African. We then estimated the total number of colonization events to Macaronesia as a whole and each constituent archipelago deriving from each region. The distribution of the origins of native non-endemic lineages broadly reflects the range of climates available in a given archipelago, such that a habitat filter model best explains their distributions. In contrast, for endemic lineages, combinations involving the Mediterranean region predominate across all four archipelagoes. The most species-rich lineages most commonly originate in the Canaries and subsequently disperse to younger, more isolated archipelagoes, reflecting a progression rule pattern. Different theoretical models apply depending on the scale of endemism. One pattern that transcended existing models involved instances where an archipelago that promotes ecological diversification serves as a stepping stone for the colonization of more distant archipelagoes that otherwise may not have been suitable for ancestral continental taxa, which we term the island springboard effect.

The parentage of the widespread allopolyploid Drosera anglica, a member of the carnivorous sundew genus, remains uncertain despite over 100 years of morphological, cytological, and, more recently, molecular study. Using transcriptomic and genomic data from 12 species of Drosera sect. Drosera, including four D. anglica populations and a population sometimes identified as disjunct D. intermedia, we assembled genes in HybPiper and phased sequences in HybPhaser. We estimated species relationships with phylogenetic and pairwise genetic distance methods and ploidy with heterozygosity and flow cytometry measurements. Additionally, we expanded represented taxa by analyzing new and previously published rbcL sequences. Sequences from phased subgenomes of D. anglica were highly similar to D. rotundifolia (99.60-99.80%) and D. linearis (99.79-99.95%) and showed no evidence of multiple origins despite sampling across North America, Europe, and Hawaii. Additionally, the disjunct D. intermedia from Idaho had been misidentified and is D. anglica. Sequences from the nuclear ribosomal region and rbcL of D. anglica were nearly identical to D. linearis despite their chromosomes mispairing during meiosis and counter to interpretations of limited Sanger sequencing. Drosera anglica is intermediate between its parental lineages in leaf shape and microhabitat; however, across D. sect. Drosera, neither leaf shape nor biogeographic distribution was a reliable indicator of phylogenetic relationships. Drosera anglica arose from allopolyploidy between the D. linearis lineage, representing the plastid and dominant ribosomal donor, and the D. rotundifolia lineage. Our study demonstrates the importance of taxon sampling and careful examination of complex phylogenomic data and presents an exemplar of analyzing allopolyploid relationships.

Declines in pollinator populations can reduce pollination services to plants, resulting in lower seed production. In response to these reductions, plants could increase the probability of pollinator visitation by plastically extending floral longevity. However, whether extended floral longevity increases seed production as pollinators decline depends on the limits to and costs of plasticity in longevity, both of which could be affected by drought stress. To test whether drought stress affects the limits to and costs of plasticity in floral longevity in response to pollinator decline, we exposed Lobelia siphilitica to droughted and well-watered treatments and measured floral longevity and the number of seeds produced by flowers pollinated on day 1 vs. day 5 of the female phase. If floral longevity is shorter in the droughted treatment, then drought stress could limit the expression of extended longevity. If delaying pollination until day 5 reduces seed production more in the droughted treatment, then drought stress could increase the cost of extended longevity. The droughted treatment reduced floral longevity by ~18% but did not affect the number of seeds produced by flowers pollinated on day 1 vs. day 5. Instead, delaying pollination until day 5 reduced the number of seeds by ~24% in both the droughted and well-watered treatments. Drought stress does not affect the cost of plasticity in floral longevity but could limit the expression of extended longevity. Consequently, whether extended floral longevity could increase seed production as pollinators decline may depend on human-induced changes in precipitation.

Desiccation tolerance (DT), the ability to survive near-complete cellular dehydration, is widespread in diaspores but rare in the vegetative tissues of land plants. The patchy and punctuated phylogenetic distribution of vegetative desiccation tolerance (VDT) suggests that the trait is both ancient and recurrent, yet the evolutionary trajectories remain unresolved. Here, we synthesize evidence across land plants to propose a framework for the evolution of VDT in embryophytes. We build on the current understanding of VDT as an ancestral trait, present in the gametophyte of early land plants. The transition to sporophyte dominance and resulting homiohydry in vascular plants coincides with the widespread loss of VDT, likely driven by relaxed selection for VDT, coupled with new structural constraints and anatomical innovations that facilitated water acquisition, transport, and retention. The core molecular modules of DT were retained in the diaspores of most land plants, where they served as evolutionary refugia for the essential building blocks of the trait. Some species later reestablished VDT by co-opting deeply conserved diaspore modules and evolving key anatomical innovations to support them. We argue that such reestablishments of VDT are dependent on both anatomical predispositions as well as exposure to key selective pressures and ecological filters. We conclude that VDT is not a simple presence-absence trait, but rather a modular system, subject to anatomical constraints and contingent on the ecological context. Ultimately, we suggest that VDT serves as an elegant example of how complex traits emerge, persist, and shift across time.

The maintenance of gynodioecy, female and hermaphroditic coexistence in plants, requires females to have a reproductive advantage over hermaphrodites in offspring quality, quantity, or both. Pollinators can influence this by mediating the reproductive success of females and hermaphrodites. We measured differences in pollinator-mediated fitness components between female and hermaphroditic plants in Sidalcea campestris to evaluate the role of pollinator-mediated selection in maintaining gynodioecy. We studied sex-biased pollinator dynamics across 28 gynodioecious populations of S. campestris and conducted pollen supplementation experiments in 20 of these populations. Using pollinator surveys and pollen supplementation experiments, we tested for differences in pollinator visitation rates, pollinator community composition, seed production, and pollen limitation between sexes. Hermaphrodites received an average of 2.24 times more visits than females, although pollinator community composition was similar for both sexes. The estimated average probability of female seed set was 1.7 times higher than hermaphrodites for open-pollinated flowers and 2.0 times higher for hand-pollinated flowers, providing evidence of a female reproductive advantage. Seed set in both sexes was pollen limited, and females were not more limited than hermaphrodites. Female pollen limitation was unaffected by population-level female frequency. These results revealed complex pollinator-mediated fitness differences between females and hermaphrodites. While our study demonstrated that females achieve the expected reproductive advantage for cytonuclear gynodioecy, the lack of differential pollen limitation and frequency-dependent female fitness are inconsistent with expectations of stable gynodioecy. Additional environmental, ecological, and genetic factors may regulate population dynamics in this gynodioecious system.

We conducted population genetic and phylogenomic analyses of several cultivated Piper nigrum varieties and closely related species. We sought to establish (1) the genetic constitution of P. nigrum and its putative status as an allotetraploid hybrid of Indian origin, and (2) its relationships to other species of Piper in South and Southeast Asia. We analyzed high-quality data comprising single nucleotide polymorphisms (SNPs) using RAxML, a phylogenetic network approach, and coancestry analyses to examine phylogenetic relationships. We included two putative parental species of the hypothesized allotetraploid P. nigrum (P. galeatum and P. trichyostachyon) and a set of Sri Lankan endemic species. We also determined genome sizes of several species. A clade comprising Sri Lankan endemics is more closely related to cultivated P. nigrum than the two Indian species. Most cultivated varieties of P. nigrum are autotetraploids that can be distinguished genetically, but among them are some diploid accessions. Piper nigrum is a member of a clade of Sri Lankan endemics and did not originate via hybridization between the previously suggested parental species, P. galeatum and P. trichostachyon. Autotetraploid varieties of Piper nigrum are predominant in cultivation, probably due to their increased vigor and higher yields, although diploid varieties are also present, demonstrating that genome duplication probably occurred recently in cultivation.

Flowers and fruits are two major phases of plant reproduction that often use colorful signals to attract animal mutualists. Fruits develop from the ovaries of flowers, and both organs use the same suites of pigments to create color. These developmental links and functional similarities led us to test for correlations in flower and fruit color lability across clades. We selected 51 clades (2960 species) of animal-pollinated and animal-dispersed (i.e., fleshy-fruited) plants and scored flower and fruit color into eight discrete (human-perceived) categories for the same set of species in each clade. We used stochastic character mapping to estimate the number and rates of transitions among colors in flowers and fruits. The number of transitions in flower and fruit color was negatively correlated across clades (R2&#x2009;=&#x2009;0.41; P&#x2009;<&#x2009;0.001). Among animal-pollinated and animal-dispersed clades, 67% were "fruit clades" biased toward fruit color lability, while 29% were "flower clades" biased toward flower color lability. Furthermore, clades with yellow- or orange-flowered species also tended to have those colors in their fruits, and red flowers were more common in "flower clades" and brown fruits in "fruit clades". These patterns suggest that clades specialize on one phase of reproduction or the other. Possible explanations include constraints on energetic investment into either pollination or dispersal, environmental factors that select for color diversification in one organ but not the other, or constraints imposed by the underlying structure of pigment pathways.

Plants in ex situ conservation nurseries acquire diverse fungal associates that may be moved among nurseries or into the wild during outplanting, including fungal endophytes that contribute to a broad range of functions and occur in leaves, sometimes alongside pathogens. To improve understanding of fungal symbionts in a plant of high conservation concern, we characterized foliar fungal endophytes of Torreya taxifolia, one of the world's most threatened conifers, in an ex situ conservation nursery. We used culture-based and culture-free approaches to characterize fungal endophytes in leaves of T. taxifolia over 2 years and evaluated how endophytes varied spatially and as a function of environmental, plant-specific, and edaphic factors. We also contrasted them with fungi in other plants (local species and species cultivated at a regional scale) and with soil fungi. Culture-free methods revealed species-rich and phylogenetically diverse foliar fungal endophytes of T. taxifolia that vary spatially, reflecting symbiont acquisition from nearby plants, environmental factors, and plant stress. Endophyte community composition is subject to both stochasticity and temporal turnover and differs markedly from fungal communities in soils and other plants in the area. Our study provides novel insights into factors that can shape fungal endophyte communities for a critically endangered tree species. In addition to identifying local determinants of endophytic symbioses, our work illustrates that plants in conservation nurseries host rich foliar fungal communities of potential importance in plant germplasm protection.

Hybrids commonly display transgressive characters, which fall outside the range exhibited by progenitors and can provide an adaptive hybrid advantage. Transgressive characters have often been documented, but the molecular bases underlying them have rarely been determined. Here, we investigated the molecular basis of transgressive delphinidin and transgressively high flavonol levels in flowers of Nicotiana section Repandae allotetraploids to determine whether these pigments are driven by differential expression and/or coding sequence evolution and, if coding sequence evolution is involved, whether there is evidence of complementation of the progenitors or resurrection of gene function in allotetraploids. We analyzed transcriptomes of corolla tissue from buds at 60%, 85%, and 95% of the mean corolla length at anthesis from Nicotiana section Repandae allotetraploids and their diploid progenitors. We examined differential expression of flavonoid biosynthetic pathway (FBP) genes and correlated transcript levels with pigment composition. Diploid progenitors lacked anthocyanins due to a nonfunctional F3'5'H and a retained intron that leads to a premature stop codon in ANS in N. sylvestris and to premature stop codons in ANS in N. obtusifolia. Differential expression of FBP genes sufficiently explains floral pigment composition in Nicotiana section Repandae allotetraploids. Differential expression drives the production of transgressive delphinidin and transgressive flavonol levels in Nicotiana section Repandae allotetraploids, and there is no evidence for complementation nor gene resurrection. Transgressive delphinidin may provide an adaptive advantage to increase pollinator attraction in N. repanda and protect against UV radiation in N. nudicaulis.

Juncaceae has needed taxonomic revision for some time. Specifically, the genus Juncus s.l. is known to be paraphyletic because five small southern-hemisphere genera have been shown repeatedly to be nested within it. In 2022, a new classification was proposed, based on phylogenies built from one nuclear and three plastid regions sequenced across much of Juncaceae, meant to resolve the paraphyletic nature of Juncus s.l. It created six new genera and was criticized on the basis that the genera proposed are not necessarily monophyletic, given the limited nature of the phylogenetic analyses available and the fact that the generic circumscriptions draw heavily on the morphology-based classifications in the latest monograph of Juncaceae from 2002. We used the Angiosperms 353 target capture probe set to assemble a data set consisting of hundreds of plastid and nuclear loci to assess the monophyly of the newly proposed genera of Juncaceae. The proposed genera mostly represent monophyletic groups, but the proposed genus Juncinella is nested within the proposed genus Boreojuncus. Additionally, Juncinella capitata was placed as sister to either Luzula or Oreojuncus and should be recognized as a monotypic genus. Finally, Australojuncus cyperoides and Verojuncus chlorocephalus were recovered outside of their morphologically assigned genera and require further investigation to be placed confidently. We proposed taxonomic revisions to rectify the stated issues, but further research is necessary, particularly to correctly place the South African annual taxa in Juncus s.l.

Plant species with affinity for harsh substrates often have well-defined edaphic (soil) niches and are ideal for exploring questions of community assembly. Vertic clay soils are chemically and physically challenging to plant establishment and productivity, and annual plant communities associated with these soils of the San Joaquin Desert (California, USA) form a distinctive mosaic pattern of species that reflects differences in soil properties across the landscape. We analyzed soil properties to determine how heterogeneous soils at two field sites in the San Joaquin Desert differed among the realized niches of 12 native annual forb species with an affinity for vertic clay soils. We then conducted a pot study with the same species to test if species differed in their realized and fundamental edaphic niches, and to examine the competition effects of an invasive annual grass (Bromus rubens) on these species' edaphic niches. From our field study, we found some differences in the vertic clay soils between the realized niches of species at both sites. In our pot study, we found species had similar fundamental edaphic niche optima in our treatment soils and that several species' competitive ability varied with the edaphic stress in our treatment soils. For some species, differences in competitive ability led to shifts in edaphic niche optima, likely contributing to more divergent realized niches. The combination of competitive pressure and abiotic stress drove differences between the realized niche and fundamental niche for species in a novel, heterogeneous study system.

Interpretations of evolutionary outcomes are limited without incorporation of physiological ecology, and ecophysiological interpretations would benefit from incorporating evolutionary perspectives. Although there has been a rise of studies in the last 20 years between these fields, evolutionary studies that incorporate plant physiology have largely focused on the same traits (e.g., flowering time, specific leaf area), neglecting cellular and developmental traits. This neglect is largely due to the high throughput demands in evolutionary studies and the lack of technological advancements in ecophysiology. However, this bias in measured traits has resulted in limiting our understanding of the evolution of plant form and function. On the other hand, most detailed studies on plant physiological and anatomical responses to the environment are either in applied sciences, focused on economically important plants, or examine model organisms rather than wild populations. These detailed ecophysiological studies generally do not incorporate evolutionary discourse, even though they often study adaptation. The aim of this synthesis is to offer a comprehensive resource, building upon previous works, for researchers to bridge the gap between ecophysiology and evolutionary ecology.

Insect herbivory is a major biotic factor shaping plant populations and driving the evolution of defensive traits. Polyploidy (whole-genome duplication) often induces substantial phenotypic and genotypic changes that may affect species interactions, including herbivory. However, natural variation in herbivory responses and the drivers of resistance and tolerance across heteroploid lineages remain poorly understood. We conducted a bioassay to quantify variation in plant damage and tolerance to locust herbivory across multiple diploid and allotetraploid populations of the Brachypodium distachyon species complex, a model system comprising two diploid species (B. distachyon and B. stacei) and their allotetraploid derivative (B. hybridum). For each species, we also examined which plant functional traits were associated with resistance and tolerance to herbivory. Herbivory reduced maternal fitness across the species complex, although its magnitude depended on species and the fitness component considered. Our results do not support enhanced herbivory resistance or tolerance in the allotetraploid lineage: Levels of plant damage in B. hybridum were comparable to those of one diploid parent (B. distachyon), and diploid B. distachyon had higher tolerance than B. hybridum for two of three fitness estimators. Variation in resistance was associated with differences in plant traits, particularly C:N ratio and silica content. In B. distachyon, tolerance was negatively associated with silica and water content, suggesting allocation trade-offs between resistance- and tolerance-related traits. Overall, our findings indicate that variation in herbivory responses across Brachypodium populations is more closely linked to population history and trait differentiation than to polyploid formation per se.