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Summary Grasses (Poaceae) comprise c. 11 800 species and are central to human livelihoods and terrestrial ecosystems. Knowing their relationships and evolutionary history is key to comparative research and crop breeding. Advances in genome‐scale sequencing allow for increased breadth and depth of phylogenomic analyses, making it possible to infer a new reference species tree of the family. We inferred a comprehensive species tree of grasses by combining new and published sequences for 331 nuclear genes from genome, transcriptome, target enrichment and shotgun data. Our 1153‐tip tree covers 79% of grass genera (including 21 genera sequenced for the first time) and all but two small tribes. We compared it to a newly inferred 910‐tip plastome tree. We recovered most of the tribes and subfamilies previously established, despite pervasive incongruence among nuclear gene trees. The early diversification of the PACMAD clade could represent a hard polytomy. Gene tree–species tree reconciliation suggests that reticulation events occurred repeatedly. Nuclear–plastome incongruence is rare, with very few cases of supported conflict. We provide a robust framework for the grass tree of life to support research on grass evolution, including modes of reticulation, and genetic diversity for sustainable agriculture. [ABSTRACT FROM AUTHOR]

In this study, we explored the distributions of grass genera in the Southern Cone (SC) of South America, applying several phylogenetic diversity (PD) metrics and randomization tests. Grasses appear to have been present in South America since their early evolution as tropical understory species more than 60 Ma. During the course of evolution, grasses have adapted to all terrestrial biomes and become one of the most successful plant families on earth. At present, the SC contains nearly all terrestrial biomes and a wide range of humid to arid ecoregions. Analyzing 126.514 point occurrences and four plastid markers for 148 genera (91% of the native grass genera), we found that tropical humid regions hold the highest PD, with no observed bias in branch lengths. These results indicate that niche conservatism dominates the diversity pattern of grasses in the SC. We found significantly low PD in the Dry Chaco and in the Patagonian Steppe, which suggest ecological filtering in both warm and cold arid regions. The Patagonian Steppe also holds significantly longer branches than expected by chance, as the native grass flora is mainly composed of distantly related Pooideae genera with a northern hemisphere origin. Short branches are found in the Uruguayan Savanna, suggesting that these grasslands could be a cradle for grass diversity within the SC. The dated phylogeny supported the current view of a relatively recent evolution of the family within the SC, with most diversification taking place from the middle Miocene and onwards. [ABSTRACT FROM AUTHOR]

Premise: Seed dispersal is a critical process impacting individual plants and their communities. Plants have evolved numerous strategies and structures to disperse their seeds, but the evolutionary drivers of this diversity remain poorly understood in most lineages. We tested the hypothesis that the evolution of wind dispersal traits within the melicgrasses (Poaceae: Meliceae Link ex Endl.) was correlated with occupation of open and disturbed habitats. Methods: To evaluate wind dispersal potential, we collected seed dispersal structures (diaspores) from 24 melicgrass species and measured falling velocity and estimated dispersal distances. Species' affinity for open and disturbed habitats were recorded using georeferenced occurrence records and land cover maps. To test whether habitat preference and dispersal traits were correlated, we used phylogenetically informed multilevel models. Results: Melicgrasses display several distinct morphologies associated with wind dispersal, suggesting likely convergence. Open habitat taxa had slower‐falling diaspores, consistent with increased wind dispersal potential. However, their shorter stature meant that dispersal distances, at a given wind speed, were not higher than those of their forest‐occupying relatives. Species with affinities for disturbed sites had slower‐falling diaspores and greater wind dispersal distances, largely explained by lighter diaspores. Conclusions: Our results are consistent with the hypothesized evolutionary relationship between habitat preference and dispersal strategy. However, phylogenetic inertia and other plant functions (e.g., water conservation) likely shaped dispersal trait evolution in melicgrasses. It remains unclear if dispersal trait changes were precipitated by or predated changing habitat preferences. Nevertheless, our study provides promising results and a framework for disentangling dispersal strategy evolution. [ABSTRACT FROM AUTHOR]

Premise: The wheat tribe, Triticeae, has been the subject of molecular phylogenetic analyses for nearly three decades, and extensive phylogenetic conflict has been apparent from the earliest comparisons among DNA‐based data sets. While most previous analyses focused primarily on nuclear vs. chloroplast DNA conflict, the present analysis provides a broader picture of conflict among nuclear loci throughout the tribe. Methods: Exon data were generated from over 1000 nuclear loci using targeted sequence capture with custom baits, and nearly complete chloroplast genome sequences were recovered. Phylogenetic conflict was assessed among the trees from the chloroplast genomes, the concatenated nuclear loci, and a series of nuclear‐locus subsets guided by Hordeum chromosome gene maps. Results: At the intergeneric level, the analyses collectively revealed a few broadly consistent relationships. However, the prevailing pattern was one of extensive phylogenetic conflict throughout the tribe, among both deep and shallow branches, and with the extent of the conflict varying among data subsets. Conclusions: The results suggest continual introgression or lineage sorting within and among the named lineages of the Triticeae, shaping both deep and shallow relationships in the tribe. [ABSTRACT FROM AUTHOR]

Diatraea saccharalis Fabricius (Lepidoptera: Crambidae), known as sugarcane borer, is the most damaging pest of sugarcane (Saccharum officinarum L., Poaceae) in northwestern Argentina and it causes significant losses in sugar and ethanol production. Currently, chemical and biological controls are used, along with host plant resistance, but there is a clear trend toward adoption of integrated pest management strategies. Considering the potential environmental and health risks associated with using agrochemicals, our study focuses on utilizing bioactive natural products, specifically plant secondary metabolites. Senecio rudbeckiaefolius Meyen & Walp (Asteraceae) is a perennial shrub found in southern Peru, Bolivia, and northwestern Argentina, valued for its use in traditional medicine. The main compounds of the genus Senecio are sesquiterpenes, with some species containing pyrrolizidine alkaloids (PAs), known for their harmful effects on herbivorous insects and vertebrates. Plant extracts exhibit several modes of action, encompassing confusion, feeding deterrence, growth regulation, insecticidal, and repellent effects. Our goal was to analyze the chemical composition of an ethanolic extract (EE) of S. rudbeckiaefolius and evaluate its lethal and sublethal effects on D. saccharalis larvae. We also investigated the potential target sites affected by the ingestion of an alkaloidal fraction from the EE (AFEE) through a midgut histological study. The main secondary metabolites identified were the PAs and phenolic compounds, with the highest concentrations found in the flowers and leaves. The majority of the PAs identified were senecionine and integerrimine. Toxicity bioassays were carried out with larvae fed on a diet supplemented with an EE of S. rudbeckiaefolius. Concentration‐dependent mortality and a marked inhibition of larval growth were recorded. We described the midgut histological structure and compared it with that of AFEE‐fed larvae. Various morphological changes were observed in the intestinal epithelium, especially an increase in the number of goblet cells and pronounced acidophilic secretion in the lumen. These results suggest that the EE of S. rudbeckiaefolius could be promising for D. saccharalis control. [ABSTRACT FROM AUTHOR]

Summary: C4 photosynthesis is a complex trait requiring multiple developmental and metabolic alterations. Despite this complexity, it has independently evolved over 60 times. However, our understanding of the transition to C4 is complicated by the fact that variation in photosynthetic type is usually segregated between species that diverged a long time ago.Here, we perform a genome‐wide association study (GWAS) using the grass Alloteropsis semialata, the only known species to have C3, intermediate, and C4 accessions that recently diverged. We aimed to identify genomic regions associated with the strength of the C4 cycle (measured using δ13C), and the development of C4 leaf anatomy.Genomic regions correlated with δ13C include regulators of C4 decarboxylation enzymes (RIPK), nonphotochemical quenching (SOQ1), and the development of Kranz anatomy (SCARECROW‐LIKE). Regions associated with the development of C4 leaf anatomy in the intermediate individuals contain additional leaf anatomy regulators, including those responsible for vein patterning (GSL8) and meristem determinacy (GIF1).The parallel recruitment of paralogous leaf anatomy regulators between A. semialata and other C4 lineages implies the co‐option of these genes is context‐dependent, which likely has implications for the engineering of the C4 trait into C3 species. [ABSTRACT FROM AUTHOR]

The genus Clavibacter (family Microbacteriaceae) includes gram‐positive actinobacterial species infecting diverse agricultural crops such as alfalfa, maize, pepper, potato, tomato and wheat. Clavibacter tessellarius, causing bacterial mosaic of wheat, was reported for the first time in 1976 in Nebraska (United States). Since then, the pathogen was thought to be restricted to North America (Canada and the United States). While bacterial strains suspected to be C. tessellarius have occasionally been isolated from wheat samples outside North America, occurrence of the pathogen in the Old World has not yet been confirmed by the plant protection authorities. In spring 2020 (January to May) dozens of wheat fields with young plants showing leaf chlorosis and mild mosaic symptoms were surveyed and sampled in southern Iran. Among 192 surveyed wheat fields, gram‐positive, orange‐pigmented actinobacterial strains were isolated from samples of 53 fields. Altogether, 61 bacterial strains were identified as C. tessellarius based on the phenotypic features, PCR‐based molecular tests and pathogenicity assays. Multilocus sequence analysis of five housekeeping genes (atpD, dnaK, gyrB, ppk and rpoB) using 10 representative strains from diverse geographic areas in southern Iran confirmed the phylogenetic status of the strains within C. tessellarius. Our data indicate that the bacterial mosaic pathogen occurs in four southern Iranian provinces including Bushehr, Fars, Kerman and Khuzestan. Thus, occurrence of C. tessellarius outside North America is confirmed. Potential risks associated with the emergence of the pathogen in the Old World, and the need for strict quarantine measures in the area, is further discussed. [ABSTRACT FROM AUTHOR]

Premise: The proportion of polyploid plants in a community increases with latitude, and different hypotheses have been proposed about which factors drive this pattern. Here, we aimed to understand the historical causes of the latitudinal polyploidy gradient using a combination of ancestral state reconstruction methods. Specifically, we assessed whether (1) polyploidization enables movement to higher latitudes (i.e., polyploidization precedes occurrences in higher latitudes) or (2) higher latitudes facilitate polyploidization (i.e., occurrence in higher latitudes precedes polyploidization). Methods: We reconstructed the ploidy states and ancestral niches of 1032 angiosperm species at four paleoclimatic time slices ranging from 3.3 million years ago to the present, comprising taxa from four well‐represented clades: Onagraceae, Primulaceae, Solanum (Solanaceae), and Pooideae (Poaceae). We used ancestral niche reconstruction models alongside a customized discrete character evolution model to allow reconstruction of states at specific time slices. Patterns of latitudinal movement were reconstructed and compared in relation to inferred ploidy shifts. Results: No single hypothesis applied equally well across all analyzed clades. While significant differences in median latitudinal occurrence were detected in the largest clade, Poaceae, no significant differences were detected in latitudinal movement in any clade. Conclusions: Our preliminary study is the first to attempt to connect ploidy changes to continuous latitudinal movement, but we cannot favor one hypothesis over another. Given that patterns seem to be clade‐specific, more clades must be analyzed in future studies for generalities to be drawn. [ABSTRACT FROM AUTHOR]

Species' persistence in increasingly variable climates will depend on resilience against the fitness costs of environmental stochasticity. Most organisms host microbiota that shield against stressors. Here, we test the hypothesis that, by limiting exposure to temporally variable stressors, microbial symbionts reduce hosts' demographic variance. We parameterized stochastic population models using data from a 14‐year symbiont‐removal experiment including seven grass species that host Epichloë fungal endophytes. Results provide novel evidence that symbiotic benefits arise not only through improved mean fitness, but also through dampened inter‐annual variance. Hosts with "fast" life‐history traits benefited most from symbiont‐mediated demographic buffering. Under current climate conditions, contributions of demographic buffering were modest compared to benefits to mean fitness. However, simulations of increased stochasticity amplified benefits of demographic buffering and made it the more important pathway of host–symbiont mutualism. Microbial‐mediated variance buffering is likely an important, yet cryptic, mechanism of resilience in an increasingly variable world. [ABSTRACT FROM AUTHOR]

We represent a comparative analysis of GBSS1 gene fragment sequences for a number of species related to Elymus caninus: Elymus prokudinii, Elymus viridiglumis, Elymus goloskokovii, as well as a number of morphologically deviating biotypes, inhabiting Russia and Kazakhstan. Microevolutionary relationships between species were assessed from dendrograms derived from sequences of exons and introns. In all taxa, the St subgenome was represented by St2 variants, rather typical of the North American ancestral line of Pseudoroegneria spicata than of the Asian line descending from Pseudoroegneria strigosa. All putative relatives of E. caninus had H1 subgenome variants linked around the Asian diploid carrier of the H genome from Hordeum jubatum and were divided into two subclades. One of them (H1‐1) contained most of the closely related E. caninus clones, including Elymus uralensis. Another subclade (H1‐2) consisted of five variants phylogenetically related to Elymus mutabilis. We have also studied reproductive relationships between species E. goloskokovii, E. prokudinii, and E. viridiglumis and the degree of their integration into the E. caninus complex. Biotypes included in sexual hybridization formed a single recombination gene pool, within which slight differences in reproductive compatibility were observed. A comprehensive study of microevolutionary differentiation of taxa showed the expediency of taxonomic revision. The species mentioned should probably be relegated to the infraspecific rank within E. caninus s. l. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: Plants and agricultural practices are an integral part of human food systems and well‐being. Here, an example of an ethnobotanical research approach is provided to increase our understanding of the relationship between plants and human activities in Madagascar, where the agricultural sector is the local economy basis. This research examines weeds of the Poaceae family, assessing their recognition and societal impacts, and quantifying farmers' perception of the Poaceae weed's status in cropping systems. A better understanding of farmers' weed knowledge will strengthen our ability to inclusively support rural highland Malagasy food systems, incorporating science with traditional knowledge. Summary: Research on the perceptions and knowledge of Poaceae weeds was conducted in three areas of Madagascar's central highlands: Itremo massif, Ambohidray village and Vakinankaratra region. This work aims to identify the best‐known species and understand their roles in crop and livestock systems. Additionally, it presents detailed data on Digitaria species.The approach was based on field surveys and farmer's interviews, with plant voucher specimens and photographs to facilitate identification. Relative frequency of citations, confidence interval, and use values indexes were calculated to assess cultural significance.We carried out 111 interviews, where 87 taxa were mentioned, of which 51 are Poaceae, including 11 Digitaria species. Farmers classify the Poaceae weeds in three ways: their impacts on agricultural activities, use category and vegetative growth patterns, the latter especially significant for Digitaria. Locally common grasses are perceived as weeds when they are abundant and cause yield loss. The most damaging species is Digitaria humbertii, confirmed by half of the interviews. More than 40% of the farmers use Poaceae weeds in composting, more than 20% as fodder, and more than 8% as medicine.Overall, 67% of the species mentioned are judged useful. The diversity of useful species and the associated indigenous knowledge is important to the local communities, but, weeds are still perceived as negative generally. The Poaceae are overall neglected in Malagasy ethnobotany, and an in‐depth analysis of farmer knowledge is needed. The data obtained will be useful for future studies and the conservation of agrobiodiversity, especially endemic species that are not widely known. [ABSTRACT FROM AUTHOR]

Premise: Leaf tensile resistance, a leaf's ability to withstand pulling forces, is an important determinant of plant ecological strategies. One potential driver of leaf tensile resistance is growing season length. When growing seasons are long, strong leaves, which often require more time and resources to construct than weak leaves, may be more advantageous than when growing seasons are short. Growing season length and other ecological conditions may also impact the morphological traits that underlie leaf tensile resistance. Methods: To understand variation in leaf tensile resistance, we measured size‐dependent leaf strength and size‐independent leaf toughness in diverse genotypes of the widespread perennial grass Panicum virgatum (switchgrass) in a common garden. We then used quantitative genetic approaches to estimate the heritability of leaf tensile resistance and whether there were genetic correlations between leaf tensile resistance and other morphological traits. Results: Leaf tensile resistance was positively associated with aboveground biomass (a proxy for fitness). Moreover, both measures of leaf tensile resistance exhibited high heritability and were positively genetically correlated with leaf lamina thickness and leaf mass per area (LMA). Leaf tensile resistance also increased with the growing season length in the habitat of origin, and this effect was mediated by both LMA and leaf thickness. Conclusions: Differences in growing season length may promote selection for different leaf lifespans and may explain existing variation in leaf tensile resistance in P. virgatum. In addition, the high heritability of leaf tensile resistance suggests that P. virgatum will be able to respond to climate change as growing seasons lengthen. [ABSTRACT FROM AUTHOR]

The cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), is a major insect pest of various agricultural crops worldwide. In this study, the effects of eight sorghum [Sorghum bicolor (L.) Moench, Poaceae] cultivars (Payam, Pegah, Sepideh, Spidfid, Kimia, KGS23, KFS2, and KFS18) on life table parameters, feeding performance, and activities of digestive enzymes in H. armigera were assessed under laboratory conditions. The insects were fed grains of the eight cultivars. Furthermore, the phytochemicals starch, proteins, flavonoids, and phenolic compounds in the grains were quantified to investigate their relationship with ecological and physiological parameters in H. armigera. Our results revealed that H. armigera had the shortest development time when reared on cv. Sepideh and the longest development time when reared on cv. Payam. The insects reached the highest and lowest intrinsic rate of increase (r) on cv. Sepideh and Payam, respectively. The relative growth rate (RGR) and efficiency of conversion of digested food (ECD) of larvae were highest and lowest on cv. Sepideh and Payam, respectively. Larval proteolytic activity was highest on cv. KFS18 and lowest on cv. Sepideh. Concerning phytochemicals, protein content was highest in cv. KFS18 and lowest in cv. Payam and KGS 23. Total phenolic levels were highest in cv. Payam and lowest in cv. Sepideh. According to the correlation analysis, overall, plant protein content was negatively correlated with insect development time, but positively correlated with pupal weight and r. Total phenolic content was positively correlated with insect development time, and negatively correlated with r and RGR. Cluster analysis indicated that cv. Sepideh was the most susceptible host, whereas cv. Payam was the most resistant. Therefore, cv. Payam may be a candidate for use in integrated pest management (IPM) against H. armigera. [ABSTRACT FROM AUTHOR]

Grasses are one of the most successful and dispersed plant families worldwide and their environmental and economic values are widely acknowledged. They dominate the landscape of Cabo Verde, the southernmost and driest archipelago of Macaronesia, and are relevant natural resources for local populations, but a comprehensive evaluation of their distribution patterns is still lacking. In this study, we aim to evaluate the potential effects of climate change using the long‐term data concerning grass distribution in Cabo Verde and the widely recognized climatic variability of this archipelago, which entails a huge irregularity in spatial and temporal rainfall. We identified two contrasting climatic periods (wet, from 1929 to 1968, and dry, from 1969 to 2007) and gathered all the information available from the bibliography, herbaria, and fieldwork concerning spontaneous grass species recorded in Cabo Verde during those two periods, which amounted to 107 taxa. This information was then used to disclose the patterns of grass diversity as related to climatic and topographic variables (altitude and windward vs. leeward aspects). Different altitudinal shifts in the distribution patterns of grass species assemblages and an assemblage specific to the wet period were revealed by comparing the two climatic periods. The role of exposure in delimiting the altitudinal distribution of the various assemblages was highlighted; the trade winds clearly determine the distribution of grass assemblages. We detected shifts in the distribution of grass assemblages according to the climatic periods (related to the macroclimate) and local topographic factors (associated with mesoclimates). Also, functional traits (i.e., annuals vs. perennials, C3 vs. C4 grasses, and tropical vs. temperate species) were found to vary between wet and dry periods, as well as with altitude and with slope aspect. Understanding species distributions and the role of the climatic variability of Cabo Verde is crucial to predicting how climate change will affect them and thus to support effective management and conservation actions. [ABSTRACT FROM AUTHOR]

Many plant species can exhibit remarkable variation in leaf characteristics, depending on their abiotic and biotic environment. Environmental changes therefore have the potential to alter leaf traits, which in turn scale up to influence ecosystem processes including net primary productivity, susceptibility to fire, and palatability to herbivores. It is not well understood how consistent trait–environment relationships are among species, across sites and over time. This presents a fundamental challenge for functional ecology, because no study can measure all relevant species in all places at all times. Thus, understanding the limits of transferability is critical. We collected leaf trait measurements on 13 species of grass (family: Poaceae) across 11 sites and five years (n = 3091 individuals). Sites were arrayed along a spatial precipitation gradient in coastal northern California (annual precipitation of 590–1350 mm) with substantial interannual precipitation variability (from 60% below the 30‐year average to 100% above average). Temporal and spatial linear relationships between precipitation and specific leaf area (SLA) appear at first idiosyncratic, with each species sometimes displaying positive and sometimes negative responses. However, this variation arises from sampling different portions of an underlying hump‐shaped relationship, which was shared across most species. This hump‐shaped relationship was driven primarily by changes in leaf tissue density. These results suggest the potential for transferability among species, as well as between space and time, as long as the gradients are sufficiently long to capture the nonlinear response. Future work could explore the physiological basis of the nonlinear SLA response, including the possibility that distinct physiological mechanisms are operating at the two extremes of the gradient. [ABSTRACT FROM AUTHOR]

The taxonomic identity and typification of Hemisorghum venustum (Thwaites) Clayton and Capillipedium parviflorum (R.Br.) Stapf. is discussed along with detailed descriptions, photographs, and notes. Morphological differences are presented for easy identification of both the species. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: Madagascar's children are taught that their ancestors destroyed the vast ancient forest, giving rise to modern grasslands, a misleading myth that continues to undermine people's relationship with nature. Replacing this myth with a more nuanced and accurate narrative around grassy ecosystems is fundamental to building a more positive relationship between Madagascar's people and ecosystems, a process that is necessary to build modern conservation practice and environmental governance. The data we present are consistent with a pre‐human grass flora in the region, suggesting the local grassy ecosystems should not be written off as fully anthropogenic and undesirable but are instead in need of recognition and further research attention. Summary: Grassy ecosystems cover over a quarter of dry land, with mosaics of old‐growth and recently formed anthropogenic systems appearing superficially similar to an uninformed observer. Grasses are part of a deep web of historic relationships between grassy ecosystems and local people.We collect and compile the first list of grass species (Poaceae) in north‐west Madagascar in order to make an initial evidence assessment for a pre‐human grass flora. Field surveys and voucher specimen collections were carried out. Specimen identification was performed using morphological character comparison with reference specimens, literature and personal knowledge of grasses from other parts of Madagascar.Seventy species are recorded and assigned to 44 genera. The species list is compared with regional grass checklists from central and south‐central Madagascar. Thirty‐five grasses are unique to Mahajanga, comprising 19% of the multi‐region species pool analysed; the regional species richness is comparable to that of the highlands.The main subfamilies represented are the Panicoideae (64%) and Chloridoideae (29%). Seven species are endemic to Madagascar, reflecting their evolutionary origins on the island. Many of the species are found in multiple types of habitat and substrate, while others are restricted to limited areas and habitats, and local species richness varies significantly with habitat and soil. The main disturbance regimes driving species occurrence include fire and grazing, possibly partly reflecting similar disturbances prior to human arrival. The patterns observed in the grass flora of north‐western Madagascar are overall congruent with a pre‐human grass flora. [ABSTRACT FROM AUTHOR]

Understanding how invasive species respond to changes in abiotic factors and what influences their ability to colonise newly disturbed areas is necessary to predict species expansion, prioritise management efforts, and develop ecological models. We conducted a fully factorial greenhouse experiment using rhizome fragments to examine the effects of four nutrients levels, three soil moisture levels, and two light levels (with five replicates, n = 120) on the growth and resource allocation patterns of Arundo donax, a large‐statured invasive wetland species. We predicted that A. donax's performance‐related traits—traits that directly influence the functionality and fitness of an individual—such as aboveground biomass (AGB), belowground biomass (BGB), net photosynthesis, and average stem height, would be highest under high light, high soil moisture and high nutrient conditions due to the ability of aggressive invasive species to capitalise on greater resource availability. Analyses using general linear mixed‐effects models revealed significant interactions between soil moisture and light. Plants grown in saturated, high light conditions exhibited the highest values for performance‐related traits. However, contrary to predictions, nutrients did not significantly influence these traits. Multivariate analysis of variance demonstrated that nutrients did influence biomass allocation patterns, with plants grown with added nitrogen and phosphorus displaying higher AGB:BGB and stem:leaf ratios. This research highlights A. donax's unique response to nutrient addition and the plasticity of biomass allocation patterns. By understanding how invasive species respond to common abiotic factors, we can better predict their expansion and prioritise management efforts, such as focusing on areas of low overstory shading, while also providing crucial information for ecological model development. [ABSTRACT FROM AUTHOR]

Premise: In frequently burned southeastern USA pine‐grassland communities, wiregrass (Aristida stricta and A. beyrichiana) are dominant bunchgrasses whose flowers are infected during flowering by a smut fungus (Langdonia walkerae). We hypothesized that because prescribed fire timing affects wiregrass flowering patterns, it could affect smut incidence (occurrence of smut on plants) and severity of infection in inflorescences and spikelets. Because soil order could influence plant susceptibility, we hypothesized that these patterns would differ between soil orders. We hypothesized differences between species as representative of geographic variation in this ecosystem. Methods: We surveyed the incidence and severity of L. walkerae in wiregrass populations (85 populations at 14 sites) that had been prescription burned at different times during the previous year. We used binomial regressions to test whether incidence and severity differed by burn day, soil order, or species, with site as a random effect. Results: Fires that occurred in the winter were associated with significantly lower incidence than fires later in the year (as the months progressed into summer). Plants growing on Spodosol soils were significantly less likely to be infected than those on other soils. More variation in incidence, however, was explained by site, suggesting that site‐specific characteristics were important. Smut severity in inflorescences and spikelets was greater overall in populations of A. stricta than in southern populations (A. beyrichiana). Conclusions: Our findings indicate that fire timing and soil order affect L. walkerae incidence in wiregrass plants, but neither appears to be associated with greater severity. Patterns of smut infection are related to site history and geographic variation. [ABSTRACT FROM AUTHOR]

Hyperspectral remote sensing has the potential to map numerous attributes of the Earth's surface, including spatial patterns of biological diversity. Grasslands are one of the largest biomes on Earth. Accurate mapping of grassland biodiversity relies on spectral discrimination of endmembers of species or plant functional types. We focused on spectral separation of grass lineages that dominate global grassy biomes: Andropogoneae (C4), Chloridoideae (C4), and Pooideae (C3). We examined leaf reflectance spectra (350–2,500 nm) from 43 grass species representing these grass lineages from four representative grassland sites in the Great Plains region of North America. We assessed the utility of leaf reflectance data for classification of grass species into three major lineages and by collection site. Classifications had very high accuracy (94%) that were robust to site differences in species and environment. We also show an information loss using multispectral sensors, that is, classification accuracy of grass lineages using spectral bands provided by current multispectral satellites is much lower (accuracy of 85.2% and 61.3% using Sentinel 2 and Landsat 8 bands, respectively). Our results suggest that hyperspectral data have an exciting potential for mapping grass functional types as informed by phylogeny. Leaf‐level hyperspectral separability of grass lineages is consistent with the potential increase in biodiversity and functional information content from the next generation of satellite‐based spectrometers. Plain Language Summary: Understanding and identifying changes in plant diversity along broad environmental gradients requires scalable and reliable data. Spectroscopy has been shown to provide data across scales with the ability to measure plant reflectance at various extents (e.g., leaf, plot, and landscapes) with high spectral resolution and broad coverage of the electromagnetic spectrum (350–2,500 nm). In grasses, evolutionary lineage captures major axes in plant biodiversity and functional variation. We show that identifying grass evolutionary lineages from spectroscopy is possible based on common characteristics in their leaf‐level spectra. We classified 43 grass species from four sites in North America into their respective evolutionary lineages with very high accuracy (>90%) based on similarities in their leaf spectra. Classifying grass species into lineages using coarser spectral resolution data, similar to existing multispectral satellites, Sentinel 2 and Landsat 8, resulted in lower accuracy due to a loss of information from decreasing the spectral resolution. Grass lineages likely have similar spectra because of common leaf traits that evolved under similar ecological contexts. The importance of these distinctions found in the spectral reflectance of dominant grass lineages, should help our efforts in mapping and understanding grassland ecosystem function and patterns of biodiversity. Key Points: Globally dominant grass lineages are identifiable using hyperspectral leaf signaturesKey wavelengths for separating grass lineages were visible, red‐edge and shortwave infrared regions, rarely measured by multispectral sensorsHyperspectral sensors have the potential to improve remote sensing identification of grass functional types over multispectral sensors [ABSTRACT FROM AUTHOR]

The increasing reliance on native seeds for ecological restoration requires the understanding of seed traits across each species, and the testing of novel processing approaches to optimize germination outcomes. Knowledge regarding Australian native seeds is critical due to the high proportion of species manifesting some degree of seed dormancy. The evaluation of approaches to overcome dormancy and identify optimal conditions for promoting germination in native species has significant applications in the restoration of degraded ecosystems. Grasses are an important component of ecosystems in the Australian monsoonal tropics, a bioregion which covers much of northern Australia, yet they are often forgotten or poorly represented when used in restoration. We investigated the effect of seed processing technique and smoke‐based stimulants on the germination of seven species from the Kimberley region, testing three different hypotheses: (1) florets germinate less than extracted caryopses; (2) acid digestion treatments with different exposure times can enhance germination; and (3) smoke‐based treatments can increase both germination and germination speed. Floret removal was generally helpful in improving germination, whereas the response to acid and smoke‐based treatments was varied. Brief acid exposure produced no to low germination improvements, whereas longer acid treatments showed contrasting results, with some species showing significant germination increase and others showing a severe reduction in germination rate. The only species showing a clear positive germination effect of smoke‐based treatments was Triodia bynoei. These results are helpful for restoration practitioners to improve their potential use in current and future restoration programs in the Australian monsoonal tropics. [ABSTRACT FROM AUTHOR]

Premise: Herbivore pressure can vary across the range of a species, resulting in different defensive strategies. If herbivory is greater at lower latitudes, plants may be better defended there, potentially driving a latitudinal gradient in defense. However, relationships that manifest across the entire range of a species may be confounded by differences within genetic subpopulations, which may obscure the drivers of these latitudinal gradients. Methods: We grew plants of the widespread perennial grass Panicum virgatum in a common garden that included genotypes from three genetic subpopulations spanning an 18.5° latitudinal gradient. We then assessed defensive strategies of these plants by measuring two physical resistance traits—leaf mass per area (LMA) and leaf ash, a proxy for silica—and multiple measures of herbivory by caterpillars of the generalist herbivore fall armyworm (Spodoptera frugiperda). Results: Across all genetic subpopulations, low‐latitude plants experienced less herbivory than high‐latitude plants. Within genetic subpopulations, however, this relationship was inconsistent—the most widely distributed and phenotypically variable subpopulation (Atlantic) exhibited more consistent latitudinal trends than either of the other two subpopulations. The two physical resistance traits, LMA and leaf ash, were both highly heritable and positively associated with resistance to different measures of herbivory across all subpopulations, indicating their importance in defense against herbivores. Again, however, these relationships were inconsistent within subpopulations. Conclusions: Defensive gradients that occur across the entire species range may not arise within localized subpopulations. Thus, identifying the drivers of latitudinal gradients in herbivory defense may depend on adequately sampling the diversity within a species. [ABSTRACT FROM AUTHOR]

Summary: Lateral gene transfer (LGT) is the movement of DNA between organisms without sexual reproduction. The acquired genes represent genetic novelties that have independently evolved in the donor's genome. Phylogenetic methods have shown that LGT is widespread across the entire grass family, although we know little about the underlying dynamics.We identify laterally acquired genes in five de novo reference genomes from the same grass genus (four Alloteropsis semialata and one Alloteropsis angusta). Using additional resequencing data for a further 40 Alloteropsis individuals, we place the acquisition of each gene onto a phylogeny using stochastic character mapping, and then infer rates of gains and losses.We detect 168 laterally acquired genes in the five reference genomes (32–100 per genome). Exponential decay models indicate that the rate of LGT acquisitions (6–28 per Ma) and subsequent losses (11–24% per Ma) varied significantly among lineages. Laterally acquired genes were lost at a higher rate than vertically inherited loci (0.02–0.8% per Ma).This high turnover creates intraspecific gene content variation, with a preponderance of them occurring as accessory genes in the Alloteropsis pangenome. This rapid turnover generates standing variation that can ultimately fuel local adaptation. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: Lateral gene transfer (LGT) refers to the transmission of genetic material without sexual reproduction. LGT is widespread in a number of plant species, including grasses. But how these genes of foreign origin got there is presently unknown. In this review, we show that transformation techniques used to genetically modify organisms could occur in the wild and be responsible for the frequently observed grass‐to‐grass LGTs. The distinction between natural evolutionary processes and genetic engineering might be arbitrary, and its validity will be further debated as agricultural biotechnology becomes more widely used and examples of "natural genetic engineering" through LGT increase. Summary: Lateral gene transfer (LGT) is the transmission of genetic material among species without sexual reproduction. LGT was initially thought to be restricted to prokaryotes, but it has since been reported in a wide range of eukaryotes, including plants. Grasses seem to be particularly prone to LGT and frequently exchange genes among species. However, the mechanism(s) facilitating these transfers in this economically and ecologically important group of plants are debated. Here, we review vector‐mediated, direct tissue‐to‐tissue contact, wide‐crossing and reproductive contamination LGT mechanisms and discuss the likelihood of each in light of recent studies. Of particular relevance are transformation approaches that require minimal human intervention to transfer DNA among grasses in the lab that could mimic the mechanisms facilitating grass‐to‐grass LGT in the wild. These approaches include relatively simple techniques, such as pollen tube pathway‐mediated transformation, that take advantage of the permeability of the reproductive process to introduce alien genetic material from a third individual into an embryo. This process could be easily mirrored in the wild where pollen from one species lands on the stigma of another, acting as a source of alien DNA that can ultimately contaminate the reproductive process. This contamination is likely to be prevalent in wind pollinated species such as grasses, where the rates of illegitimate pollination will be high. In conclusion, plant transformation methods requiring minimal intervention are likely paralleled in the wild where they act as the mechanism underpinning LGT between distantly related grass species. [ABSTRACT FROM AUTHOR]

Plant traits are useful for predicting how species may respond to environmental change and/or influence ecosystem properties. Understanding the extent to which traits vary within species and across climatic gradients is particularly important for understanding how species may respond to climate change. We explored whether climate drives spatial patterns of intraspecific trait variation for three traits (specific leaf area (SLA), plant height, and leaf nitrogen content (Nmass)) across 122 grass species (family: Poaceae) with a combined distribution across six continents. We tested the hypothesis that the sensitivity (i.e. slope) of intraspecific trait responses to climate across space would be related to the species' typical form and function (e.g. leaf economics, stature and lifespan). We observed both positive and negative intraspecific trait responses to climate with the distribution of slope coefficients across species straddling zero for precipitation, temperature and climate seasonality. As hypothesized, variation in slope coefficients across species was partially explained by leaf economics and lifespan. For example, acquisitive species with nitrogen‐rich leaves grew taller and produced leaves with higher SLA in warmer regions compared to species with low Nmass. Compared to perennials, annual grasses invested in leaves with higher SLA yet decreased height and Nmass in regions with high precipitation seasonality (PS). Thus, while the influence of climate on trait expression may at first appear idiosyncratic, variation in trait–climate slope coefficients is at least partially explained by the species' typical form and function. Overall, our results suggest that a species' mean location along one axis of trait variation (e.g. leaf economics) could influence how traits along a separate axis of variation (e.g. plant size) respond to spatial variation in climate. [ABSTRACT FROM AUTHOR]

The fall armyworm (FAW), Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae), is a major migratory invasive pest that poses a severe threat to agricultural production and food security in China. In this study, we estimated the effects of six cereal crops on the development, survival, and fecundity of FAW using the age‐stage, two‐sex life table: maize (Zea mays L.), wheat (Triticum aestivum L.), sorghum [Sorghum bicolor (L.) Moench], oats (Avena sativa L.), millet (species, authority) (all Poaceae), and quinoa (Chenopodium quinoa Willd.) (Amaranthaceae). In a six‐choice test using detached leaf material, FAW larvae preferentially occurred on maize, followed by sorghum, within 6–24 h, and occurred the least on millet and quinoa. After 24 h, they had consumed the most leaf material from sorghum and maize, and the least from quinoa. In no‐choice tests using detached leaf material, they performed best on maize in terms of development (e.g., short development time), survival (e.g., high larval survival and pupation rate), and fecundity (e.g., high number of oviposition days and number of eggs laid per female), resulting in the highest predicted population growth (e.g., high intrinsic rate of increase and net reproductive rate). Although maize was found to be the most appropriate host plant, FAW was able to complete its life cycle on all six tested cereals. Our findings can help in predicting population dynamics and deepening our understanding of the potential damage incurred by FAW infestation, especially in regions under maize cultivation. [ABSTRACT FROM AUTHOR]

Goss's bacterial wilt and leaf blight of maize (Zea mays) caused by the gram‐positive coryneform bacterium Clavibacter nebraskensis is an economically important disease in North America. C. nebraskensis is included within the high‐risk list of quarantine pathogens by several plant protection organizations (EPPO code: CORBMI), hence it is under strict quarantine control around the world. The causal agent was reported for the first time on maize in Nebraska (USA) in 1969. After an outbreak during the 1970s, prevalence of the disease decreased in the 1980s to the early 2000s, before the disease resurged causing a serious threat to maize production in North America. The re‐emergence of Goss's wilt in the corn belt of the United States led to several novel achievements in understanding the pathogen biology and disease control. In this review, we provide an updated overview of the pathogen taxonomy, biology, and epidemiology as well as management strategies of Goss's wilt disease. First, a taxonomic history of the pathogen is provided followed by symptomology and host range, genetic diversity, and pathogenicity mechanisms of the bacterium. Then, utility of high‐throughput molecular approaches in the precise detection and identification of the pathogen and the management strategies of the disease are explained. Finally, we highlight the role of integrated pest management strategies to combat the risk of Goss's wilt in the 21st century maize industry. Disease symptoms: Large (2–15 cm) tan to grey elongated oval lesions with wavy, irregular water‐soaked margins on the leaves. The lesions often start at the leaf tip or are associated with wounding caused by hail or wind damage. Small (1 mm in diameter), dark, discontinuous water‐soaked spots, known as "freckles", can be observed in the periphery of lesions. When backlit, the freckles appear translucent. Early infection (prior to growth stage V6) may become systemic and cause seedlings to wilt, wither, and die. Coalescence of lesions results in leaf blighting. Host range: Maize (Zea mays) is the only economic host of the pathogen. A number of Poaceae species are reported to act as secondary hosts for C. nebraskensis. Taxonomic status of the pathogen: Class: Actinobacteria; Order: Micrococcales; Family: Microbacteriaceae; Genus: Clavibacter; Species: Clavibacter nebraskensis. Synonyms Corynebacterium nebraskense (Schuster, 1970) Vidaver & Mandel 1974; Corynebacterium michiganense pv. nebraskense (Vidaver & Mandel 1974) Dye & Kemp 1977; Corynebacterium michiganense subsp. nebraskense (Vidaver & Mandel 1974) Carlson & Vidaver 1982; Clavibacter michiganense subsp. nebraskense (Vidaver & Mandel 1974) Davis et al. 1984; Clavibacter michiganensis subsp. nebraskensis (Vidaver & Mandel 1974) Davis et al. 1984. Type materials: ATCC 27794T; CFBP 2405T; ICMP 3298T; LMG 3700T; NCPPB 2581T. Microbiological properties: Cells are gram‐positive, orange‐pigmented, pleomorphic club‐ or rod‐shaped, nonspore‐forming, nonmotile, and without flagella, approximately 0.5 × 1–2.0 μm. Distribution: The pathogen is restricted to Canada and the United States. Phytosanitary categorization: EPPO code CORBNE. [ABSTRACT FROM AUTHOR]

Elymus nepalensis, which was described from Nepal in the year 1960 and was considered to be endemic to Nepal and known only by the Type collections, has been rediscovered from Dzoukou valley, situated at the border of Manipur and Nagaland, India. The same has been typified with detailed description, illustration, and distribution. [ABSTRACT FROM AUTHOR]

Desiccation-tolerant vascular (DT) plants are predominant occupants of rock outcrops in tropical regions. Though rock outcrops are common landscapes in the Western Ghats (WG), a biodiversity hotspot in India, knowledge of DT plants in the region is poor. This study provides an overview of Indian DT vascular plants, emphasizing the WG, and includes an inventory of species with their habitat preferences. Outcrop species were scrutinized for their DT properties by seasonal field observations, followed by relative water content estimation protocols. The inventory revealed 62 DT species, many more than the earlier known nine species. Nine genera of DT plants are reported as new also in a global perspective, and Tripogon capillatus represent the first record of an epiphytic DT angiosperm. We also provide the first field observation-based proof of DT properties of the gesneriad Corallodiscus lanuginosus. Of the 62 species, 16 are Indian endemic, and 12 are exclusive to Western Ghat outcrops, highlighting WG's importance as a global DT hotspot. In addition to rock outcrops, partially shaded sites in forests are crucial habitats for DT species. This pioneering inventory addresses India's need for more knowledge on DT plants and opens new research avenues. [ABSTRACT FROM AUTHOR]

Despite morphological similarity of lemmas and paleas in rice, lemma gene expression is similar to that of glumes, while palea gene expression is similar to that of lodicules and reproductive organs (Zong et al., [17]). Keywords: developmental genetics; evolution of floral development; floral homology; monocots; Poaceae; sepals; tepals EN developmental genetics evolution of floral development floral homology monocots Poaceae sepals tepals 1 4 4 05/03/23 20230401 NES 230401 Plant form is astonishingly diverse. If, for instance, ChINs for bract and sepal identity were defined, they could be compared to genes involved in lemma development to determine whether lemmas rely on the leaf ChIN, sepal ChIN, or a combination of both. [Extracted from the article]

Both theory and prior studies predict that climate warming should increase attack rates by herbivores and pathogens on plants. However, past work has often assumed that variation in abiotic conditions other than temperature (e.g. precipitation) do not alter warming responses of plant damage by natural enemies. Studies over short time periods span low variation in weather, and studies over long time‐scales often neglect to account for fine‐scale weather conditions.Here, we used a 20+ year warming experiment to investigate if warming affects on herbivory and pathogen disease are dependent on variation in ambient weather observed over 3 years. We studied three common grass species in a subalpine meadow in the Colorado Rocky Mountains, USA. We visually estimated herbivory and disease every 2 weeks during the growing season and evaluated weather conditions during the previous 2‐ or 4‐week time interval (2‐week average air temperature, 2‐ and 4‐week cumulative precipitation) as predictors of the probability and amount of damage.Herbivore attack was 13% more likely and damage amount was 29% greater in warmed plots than controls across the focal species but warming treatment had little affect on plant disease. Herbivory presence and damage increased the most with experimental warming when preceded by wetter, rather than drier, fine‐scale weather, but preceding ambient temperature did not strongly interact with elevated warming to influence herbivory.Disease presence and amount increased, on average, with warmer weather and more precipitation regardless of warming.Synthesis. The effect of warming over reference climate on herbivore damage is dependent on and amplified by fine‐scale weather variation, suggesting more boom‐and‐bust damage dynamics with increasing climate variability. However, the mean effect of regional climate change is likely reduced monsoon rainfall, for which we predict a reduction in insect herbivore damage. Plant disease was generally unresponsive to warming, which may be a consequence of our coarse disease estimates that did not track specific pathogen species or guilds. The results point towards temperature as an important but not sufficient determinant and regulator of species interactions, where precipitation and other constraints may determine the affect of warming. [ABSTRACT FROM AUTHOR]

Although the agricultural use of genetically engineered (GE) plants has been employed extensively, its adoption is still controversial and its impact on arthropods has rarely been scrutinized at the community level. If this technology is aimed at a drastic reduction of a key community component, significant community‐level impact is expected and needs to be assessed. Thus, food web analysis was used to assess the short‐term impact of genetically modified maize plants, Zea mays L. (Poaceae), expressing insecticidal proteins of the bacterium Bacillus thuringiensis Berliner (i.e., Bt maize), on the associated arthropod assemblage in a neotropical scenario. Arthropods associated with winter and summer cultivations with Bt and non‐Bt (isoline) maize were thus sampled using sweep nets and whole‐plant collections throughout the plant phenological cycle. The collected information was used to build a plant‐consumer‐predator trivariate network based on data of individual arthropod body mass, numerical abundance, and biomass abundance using food web analysis. Eighty‐five arthropod species were sampled, and whereas cultivation season significantly affected arthropod species richness and abundance, only marginal differences existed between maize hybrids (Bt vs. non‐Bt). The recognized food webs also indicated significant differences between seasons. In contrast, Bt‐maize‐hosted food webs were similar to those of the non‐Bt isoline indicating no significant impact on arthropod food webs. Nonetheless, Bt maize did not provide significant control of the target pest species, the fall armyworm, nor did it lead to higher crop yield, raising questions about its current usefulness in the region. [ABSTRACT FROM AUTHOR]

Premise: Seed germination is controlled by the soil microclimate, which is expected to change with the temperature increase and rainfall irregularity predicted for the future. Because changes in soil characteristics directly affect species recruitment, vegetation dynamics and resilience, we investigated how caryopses of native grasses from dry and wet grasslands respond to water stress under current and future temperature regimes. Methods: Caryopses were collected from 10 grass species in dry and wet grasslands, subjected or not to a fire event, and tested for germination at increasing osmotic potential (0 to –1.0 MPa) at current (17°/27°C night/day) and future (23°/33°C) simulated temperatures. Results: The viability and germination percentages of caryopses from both dry and wet grassland species were progressively reduced as osmotic stress increased, irrespective of temperature regime. The viability of caryopses from wet grassland species was reduced under the future temperature regime, irrespective of osmotic potential. The slow germination of caryopses of dry grassland species at the present temperature regime was absent when they were incubated in the future temperature regime. Conclusions: More intense water stress reduced the survival of caryopses for both dry and wet grassland grass species. The predicted future temperature regime reduced the viability of wet grassland species and altered the germination strategy of dry grassland species. These results indicate that increasing water stress and temperature predicted for the future may compromise the recruitment potential of dry and wet grassland species and directly impact the dynamics and resilience of these ecosystems. [ABSTRACT FROM AUTHOR]

Many grasses (Poaceae) defend their basal meristems with silicified trichomes, prickles, and spines. These leaf features are often unidirectional, pointing from the leaf base to the tip. They have been hypothesized to direct small herbivores away from vulnerable meristems, making grasses tolerant of the loss of leaf tissue. The aim of this study was to determine whether leaves of rice (Oryza sativa L.) and broomsedge (Andropogon virginicus L.) with silicified non‐glandular trichomes and prickles experience more chewing damage to leaf tips than to leaf bases, and whether the unidirectional leaf features were responsible for this pattern. Rice and A. virginicus leaves received 4× and 3× more chewing damage, respectively, to tips than middle sections, and 3× and 8× more damage to middle sections compared to basal sections. Removing trichomes and prickles from half of each leaf did not increase the overall frequency of damage to those leaves. However, removing silicified structures caused herbivores to increase the frequency of damage to leaf sections without trichomes and prickles, including basal leaf sections. Leaves of A. virginicus were experimentally folded in half such that the middle section was above the tip and basal sections; folded leaves received more damage to tips and bases than to middle sections. This indicates that herbivores do not choose to feed on the tallest leaf tissue but are likely influenced by the orientation of the silicified leaf features. Previous studies have shown variation in silicified structures on the leaves of many crop species. As these structures are involved in directing herbivores away from basal meristems, they should be considered as targets for crop breeding. [ABSTRACT FROM AUTHOR]

Premise: Anthropogenic nitrogen (N) addition alters the abiotic and biotic environment, potentially leading to changes in patterns of natural selection (i.e., trait–fitness relationships) and the opportunity for selection (i.e., variance in relative fitness). Because N addition favors species with light acquisition strategies (e.g., tall species), we predicted that N would strengthen selection favoring those same traits. We also predicted that N could alter the opportunity for selection via its effects on mean fitness and/or competitive asymmetries. Methods: We quantified the strength of selection and the opportunity for selection in replicated populations of the annual grass Setaria faberi (giant foxtail) growing in a long‐term N addition experiment. We also correlated these population‐level parameters with community‐level metrics to identify the proximate causes of N‐mediated evolutionary effects. Results: N addition increased aboveground productivity, light asymmetry, and reduced species diversity. Contrary to expectations, N addition did not strengthen selection for trait values associated with higher light acquisition such as greater height and specific leaf area (SLA); rather, it strengthened selection favoring lower SLA. Light asymmetry and species diversity were associated with selection for height and SLA, suggesting a role for these factors in driving N‐mediated selection. The opportunity for selection was not influenced by N addition but was negatively associated with species diversity. Conclusions: Our results indicate that anthropogenic N enrichment can affect evolutionary processes, but that evolutionary changes in plant traits within populations are unlikely to parallel the shifts in plant traits observed at the community level. [ABSTRACT FROM AUTHOR]

Premise: Many studies have assessed the various responses of alien plants to changes in overall nutrient or different nitrogen (N) availabilities. However, in natural soils, nutrients are present as different elements (e.g., N and phosphorus [P]) and forms (e.g., inorganic and organic). Few studies have explored whether invasive and native species differ in their responses to varying P availability and forms. Methods: We grew five taxonomically related pairs of common herbaceous, invasive and native species alone or in competition under six different conditions of P availability or forms and assessed their growth performance. Results: Invasive species overall did not produce more biomass than native species did in the various P conditions. However, the biomass response to organic forms of P was, relative to the response to inorganic forms of P, stronger for the invasive species than that for the native species and agreed with invasive species mainly allocating biomass to the root system under organic P conditions. Conclusions: While invasive species were not more promiscuous than the native species, they took great advantage of the organic P forms. Therefore, the invasion risk of alien species may increase in habitats with more organic P sources. [ABSTRACT FROM AUTHOR]

The awn of grasses is a long, conspicuous outgrowth of the floral bracts in a grass spikelet. It is known to impact agricultural yield, but we know little about its broader ecological function, nor the selective forces that lead to its evolution. Grass awns are phenotypically diverse across the extant ~12,000 species of Poaceae. Awns have been lost and gained repeatedly over evolutionary time, between and within lineages, suggesting that they could be under selection and might provide adaptive benefit in some environments. Despite the phylogenetic context, we know of no studies that have tested whether the origin of awns correlates with putative selective forces on their form and function. Presence or absence of awns is not plastic; rather, heritability is high. The awns of grasses often are suggested as adaptations for dispersal, and most experimental work has been aimed at testing this hypothesis. Proposed dispersal functions include soil burial, epizoochory, and aerial orientation. Awns may also protect the seed from drought, herbivores, or fire by helping it become buried in soil. We do not fully understand the fitness or nutrient costs of awn production, but in some species awns function in photosynthesis, providing carbon to the seed. Here we show that awns likely provide an adaptive advantage, but argue that studies on awn function have lacked critical phylogenetic information to demonstrate adaptive convergent evolution, are taxonomically biased, and often lack clear alternative hypotheses. [ABSTRACT FROM AUTHOR]

Plants are often sequentially attacked by multiple herbivores; feeding by one herbivore can alter host plant quality that affects the performance of subsequent herbivores. Previous studies suggest that silicon (Si) is a highly inducible defence in grasses (Poaceae) following herbivory, so could mediate such temporally separated insect herbivore interactions. Elevated atmospheric CO2 concentrations (eCO2), in contrast, often reduce Si accumulation, which potentially weakens this interaction. We examined the effects of prior feeding by Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) on the performance of crickets, Acheta domesticus (L.) (Orthoptera: Gryllidae), subsequently feeding on the same plant. We used Brachypodium distachyon (L.) P. Beauv. grass supplemented or non‐supplemented with Si and grown in the glasshouse maintained at ambient (aCO2) or eCO2 concentrations. As hypothesized, prior feeding by caterpillars induced Si accumulation. Despite eCO2 reducing Si accumulation, initial herbivore induction of Si negated the effects of eCO2. Both, previous caterpillar herbivory and Si supplementation reduced cricket performance. Si induction by successive herbivory was additive. Plant biomass was similar in plants attacked by caterpillars alone or both herbivores, suggesting that initial Si induction by caterpillars deterred feeding by crickets. Our results demonstrate that Si induction by one herbivore negatively impacts successive herbivores, as has been demonstrated for secondary metabolite‐mediated interactions. Uniquely, however, Si induction is an irreversible defence and potentially a stronger, or perhaps longer‐lasting mediator of such herbivore interactions in some plant taxa. [ABSTRACT FROM AUTHOR]

Seed dormancy varies greatly between species, clades, communities, and regions. We propose that fireprone ecosystems create ideal conditions for the selection of seed dormancy as fire provides a mechanism for dormancy release and postfire conditions are optimal for germination. Thus, fire‐released seed dormancy should vary in type and abundance under different fire regimes. To test these predictions, we compiled data from a wide range of fire‐related germination experiments for species in different ecosystems across the globe. We identified four dormancy syndromes: heat‐released (physical) dormancy, smoke‐released (physiological) dormancy, non‐fire‐released dormancy, and non‐dormancy. In fireprone ecosystems, fire, in the form of heat and/or chemical by‐products (collectively termed 'smoke'), are the predominant stimuli for dormancy release and subsequent germination, with climate (cold or warm stratification) and light sometimes playing important secondary roles. Fire (heat or smoke)‐released dormancy is best expressed where woody vegetation is dense and fires are intense, i.e. in crown‐fire ecosystems. In such environments, seed dormancy allows shade‐intolerant species to take advantage of vegetation gaps created by fire and synchronize germination with optimal recruitment conditions. In grassy fireprone ecosystems (e.g. savannas), where fires are less intense but more frequent, seed dormancy is less common and dormancy release is often not directly related to fire (non‐fire‐released dormancy). Rates of germination, whether controls or postfire, are twice as fast in savannas than in mediterranean ecosystems. Fire‐released dormancy is rare to absent in arid ecosystems and rainforests. The seeds of many species with fire‐released dormancy also possess elaiosomes that promote ant dispersal. Burial by ants increases insulation of seeds from fires and places them in a suitable location for fire‐released dormancy. The distribution of these dormancy syndromes across seed plants is not random – certain dormancy types are associated with particular lineages (phylogenetic conservatism). Heat‐released dormancy can be traced back to fireprone floras in the 'fiery' mid‐Cretaceous, followed by smoke‐released dormancy, with loss of fire‐related dormancy among recent events associated with the advent of open savannas and non‐fireprone habitats. Anthropogenic influences are now modifying dormancy‐release mechanisms, usually decreasing the role of fire as exaptive effects. We conclude that contrasting fire regimes are a key driver of the evolution and maintenance of diverse seed dormancy types in many of the world's natural ecosystems. [ABSTRACT FROM AUTHOR]

Many essential oils have excellent insecticidal activity and have the potential to be developed as alternatives to chemical insecticides for pest control. Previously, we showed that β‐asarone, a major constituent of the essential oil derived from Acorus calamus L. (Acoraceae), has strong pesticidal activity against brown planthopper, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), the most notorious rice pest in Asia. Here, we report the first evaluation of the sublethal and transgenerational effects of β‐asarone on N. lugens. β‐Asarone significantly decreased female longevity, male longevity, fecundity, and hatchability of F0 generation individuals exposed to the LD30 and LD45 of β‐asarone relative to the acetone control. Moreover, compared with acetone, exposure to LD30 and LD45 of β‐asarone significantly shortened the duration of the egg stage, developmental duration of first instars, and female longevity of F1 generation individuals. Furthermore, the intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rates (R0) of insects treated with LD30 and LD45 of β‐asarone were significantly lower than those of insects treated with acetone. Compared with acetone, the fecundity and hatchability of F1 generation individuals were significantly decreased after exposure to β‐asarone at LD30 and LD45. These findings indicate the negative effects of sublethal doses of β‐asarone on N. lugens and provide novel information on the potential use of β‐asarone as a substitute chemical pesticide. [ABSTRACT FROM AUTHOR]

Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) is one of the major lepidopteran pests throughout the Western Hemisphere. In Argentina, it causes significant losses mainly in sugarcane (Saccharum officinarum L.) and corn (maize, Zea mays L.) (both Poaceae). Previous studies determined the existence of reproductive incompatibilities between populations from Buenos Aires and Tucumán from different host plants; however, the genetic basis of this incompatibility is still unknown. As the effectiveness of pest control programs mainly depends on strategies that minimize the risk of favoring insecticide‐resistant genotypes, estimating the level of mating between genotypes is important to monitor and manage resistance. The aim of this study was to characterize the genetic structure of D. saccharalis populations collected from various hosts and regions in Argentina, comparing with those from Brazil, through cytochrome c oxidase subunit I (COI) analysis and next‐generation sequencing (NGS). The COI analysis showed a haplotypic diversity of 0.8 and a nucleotide diversity of 0.0058. Analysis of molecular variance revealed greater variation within populations than among them. The 17 haplotypes detected were linked in a single parsimony network that did not reveal clusters based on geography or host plants. In total, 4549 single nucleotide polymorphism markers (SNPs) were obtained through NGS. Out of the 2349 outlier loci, 84 showed similarities with previously characterized proteins. The coefficient of inbreeding showed evidence of random matings as well as some degree of selection. The fixation index values showed high genetic variation between Argentinean and Brazilian populations; however, there was no clear trend based on distance or hosts. Similarly, the discriminant analysis of principal components revealed three separate groups: one Brazilian and two Argentinean. Results generated important clarification of the population genetic structure of D. saccharalis in South America, which provides information about routes of dispersal and the development of suitable management strategies. [ABSTRACT FROM AUTHOR]

Ungulate herbivory is a key driver of leaf trait syndromes and defense strategies at the ecological and macroevolutionary levels. Herbivory should also cause short‐term evolution within plant populations, but few studies have experimentally tested this prediction. We set out to experimentally assess the plastic and heritable effects of contemporary history of ungulate herbivory on 1) leaf trait syndromes at the intraspecific level, and on the defense traits, 2) leaf size and 3) size of spines. We measured leaf traits (specific leaf area, leaf dry matter content, leaf nitrogen concentration and leaf mechanical resistance) in populations of six grass and four woody legume species that had grown under contrasting pressures of domestic ungulate herbivory for at least 40 years. We then performed a common garden experiment, measuring the same traits. Next, we performed cutting experiments on the plants grown in the common garden to measure leaf trait plasticity. In the woody species, we also measured the length of spines and the leaf size (average area per leaf), in the field and in the common garden experiment. We found that in grasses field herbivory over decades produced a displacement toward more acquisitive leaf trait syndromes. Most of these changes appeared largely due to plasticity. In woody legume species, in contrast, herbivory produced a displacement towards more conservative leaves, longer spines and smaller leaves, with the trait differences between histories of herbivory being mostly hereditary. These results point out that vertebrate herbivory can lead to evolutionary processes at contemporary time scales even in long‐lived perennial plant species, but the direction of such change depends on the life form of the species. These divergent effects could depend on the predominant anti‐herbivore strategies in the different life forms (tolerance versus resistance). [ABSTRACT FROM AUTHOR]

Flower visitors use different parts of the landscape through the plants they visit, however these connections vary within and among land uses. Identifying which flower‐visiting insects are carrying pollen, and from where in the landscape, can elucidate key pollen–insect interactions and identify the most important sites for maintaining community‐level interactions across land uses. We developed a bipartite meta‐network, linking pollen–insect interactions with the sites they occur in. We used this to identify which land‐use types at the site‐ and landscape‐scale (within 500 m of a site) are most important for conserving pollen–insect interactions. We compared pollen–insect interactions across four different land uses (remnant native forest, avocado orchard, dairy farm, rotational potato crop) within a mosaic agricultural landscape. We sampled insects using flight intercept traps, identified pollen carried on their bodies and quantified distinct pollen–insect interactions that were highly specialized to both natural and modified land uses. We found that sites in crops and dairy farms had higher richness of pollen–insect interactions and higher interaction strength than small forest patches and orchards. Further, many interactions involved pollinator groups such as flies, wasps, and beetles that are often under‐represented in pollen–insect network studies, but were often connector species in our networks. These insect groups require greater attention to enable wholistic pollinator community conservation. Pollen samples were dominated by grass (Poaceae) pollen, indicating anemophilous plant species may provide important food resources for pollinators, particularly in modified land uses. Field‐scale land use (within 100 m of a site) better predicted pollen–insect interaction richness, uniqueness, and strength than landscape‐scale. Thus, management focused at smaller scales may provide more tractable outcomes for conserving or restoring pollen–insect interactions in modified landscapes. For instance, actions aimed at linking high‐richness sites with those containing unique (i.e., rare) interactions by enhancing floral corridors along field boundaries and between different land uses may best aid interaction diversity and connectance. The ability to map interactions across sites using a meta‐network approach is practical and can inform land‐use planning, whereby conservation efforts can be targeted toward areas that host key interactions between plant and pollinator species. [ABSTRACT FROM AUTHOR]

In classification and identification of plant species, palyno morphological character has remain helpful for plant taxonomist. The aim to investigation this study was to identify the characteristic features of Asteraceae and Poaceae family member collected from lower Himalayas of Pakistan. Light microscope and Scanning electron microscope were used for feature study of allergenic pollen. Our study includes 10 species of Asteraceae and Poaceae family. The most dominant shape of pollen was Oblate‐spheroidal, Prolate‐Spheroidal, Prolate and Suboblate shape of pollen. Quantitative character of pollen includes maximum pollen diameter found in Dichanthium annulatum (46.0 μm) and minimum polar axis pollen diameter found in Parthenium hysterophorous (16.0 μm). Similarly highest value of P/E ratio was noted in Cenchrus echinatus (1.05) and smallest value of P/E ratio was observed in Erigeron bonariensis (0.88). Poaceae family member were monoporate. Character feature of exine sculpturing include Microechinate, granulate, echinate, conical base, lacunae Nanogammate, Aerolate‐Scabratre, Verrucate, like variation found in exine of both family member. Highest value of pollen fertility was observed in P. hysterophorous 93%, Similarly maximum value of pollen sterility was noted in E. bonariensis and Brachiaria reptans 24%. This investigation provides the characteristic feature of allergenic pollen species and help to arrange them in define class. Research Highlights: Pollen has affected many people around the world.Using microscopic techniques, morpho‐palynological analysis of Asteraceae and Poaceae families were recognized.LM and SEM study show both qualitative and quantitative character of pollen.Identification of allergenic pollen and microscopic identified character play important role for proper guideline of identification of pollen having allergenic potential. [ABSTRACT FROM AUTHOR]

C4 photosynthesis is thought to have evolved via intermediate stages, with changes towards the C4 phenotype gradually enhancing photosynthetic performance. This hypothesis is widely supported by modelling studies, but experimental tests are missing. Mixing of C4 components to generate artificial intermediates can be achieved via crossing, and the grass Alloteropsis semialata represents an outstanding study system since it includes C4 and non‐C4 populations. Here, we analyse F1 hybrids between C3 and C4, and C3+C4 and C4 genotypes to determine whether the acquisition of C4 characteristics increases photosynthetic performance. The hybrids have leaf anatomical characters and C4 gene expression profiles that are largely intermediate between those of their parents. Carbon isotope ratios are similarly intermediate, which suggests that a partial C4 cycle coexists with C3 carbon fixation in the hybrids. This partial C4 phenotype is associated with C4‐like photosynthetic efficiency in C3+C4 × C4, but not in C3 × C4 hybrids, which are overall less efficient than both parents. Our results support the hypothesis that the photosynthetic gains from the upregulation of C4 characteristics depend on coordinated changes in anatomy and biochemistry. The order of acquisition of C4 components is thus constrained, with C3+C4 species providing an essential step for C4 evolution. Summary statement: We analyse hybrids between C3 and C4, and C3+C4 and C4 accessions of the grass Alloteropsis semialata. While hybrids have upregulated C4 features, these do not consistently increase photosynthetic efficiency, highlighting the importance of the order of acquisition of components during C4 evolution. [ABSTRACT FROM AUTHOR]

Species of the Heteropogon‐Themeda clade are ecologically important grasses distributed across the tropics, including widespread species, such as the pantropical Heteropogon contortus and Themeda triandra, and range‐restricted species such as Heteropogon ritchiei and Themeda anathera. Here, we examine habitat preferences of the grassland/savanna and wetland species by describing bioclimatic niche characteristics, characterizing functional traits, and investigating the evolution of functional traits of 31 species in the Heteropogon‐Themeda clade in relation to precipitation and temperature. The climatic limits of the clade are linked to mean annual precipitation and seasonality that also distinguish seven wetland species from 24 grassland/savanna species. Tests of niche equivalency highlighted the unique bioclimatic niche of the wetland species. However, climatic factors do not fully explain species geographic range, and other factors are likely to contribute to their distribution ranges. Trait analyses demonstrated that the wetland and grassland/savanna species were separated by culm height, leaf length, leaf area, awn length, and awn types. Phylogenetic analyses showed that the wetland species had tall stature with long and large leaves and lack of hygroscopic awns, which suggest selective pressures in the shift between savanna/grassland and wetland. The two most widespread species, H. contortus and T. triandra, have significantly different bioclimatic niches, but we also found that climatic niche alone does not explain the current geographic distributions of H. contortus and T. triandra. Our study provides a new understanding of the biogeography and evolutionary history of an ecologically important clade of C4 tropical grasses. [ABSTRACT FROM AUTHOR]

To investigate the evolutionary relationships among species of Afrotrichloris, Apochiton, Coelachyrum, Dinebra, Eleusine, Leptochloa, and Schoenefeldia of subtribe Eleusininae, a phylogeny based on DNA sequences from nine gene regions (ITS, rps16‐trnK, rps3, rps16, rpoC2, rpl32‐trnL, ndhF, ndhA, ccsA) is presented. Previous molecular phylogenies indicated that Coelachyrum was polyphyletic and Schoenefeldia was paraphyletic, with Afrotrichloris embedded within it. Apochiton burttii was embedded in the Coelachyrum clade paired with C. longiglume, Coelachyrum poiflorum was placed outside of Coelachyrum and sister to Eleusine, and Schoenefeldia is paraphyletic, with its two species forming a grade sister to Afrotrichoris. Our molecular phylogeny supports recognition of a new genus, Schoenefeldiella, and a new combination, Schoenfeldiella transiens. In addition, we provide generic emendations for Coelachyrum, which now includes five species including a new combination proposed here, Coelachyrum burttii, and Eleusine, which now includes 11 species. [ABSTRACT FROM AUTHOR]

This study highlighted the taxonomic utilization of palynological metaphors for selected members (53) of family Poaceae. Multiple microscopic technique light and scanning electrons had been employed for detailed analysis. Results reported monad pollen type in all studied 53 members, which showed its limited taxonomic value up to family level. In relation to shape of pollen both polar and equatorial views strikingly differed from each other. Like semi angular pollen observed in Dactyloctenium aegyptium (L.) Wild. whereas round‐minutely irregular pollen in Lolium temulentum L. Polar and equatorial diameter also showed variation, that is, Desmostachya bipinnata (L.) Stapf. can be differentiated from Sorghum bicolor (L.) Moench on diameter variation basis. A pore characteristic does not show much qualitative variation; however pore sizes differ species to species. The most frequently scarbate sculpturing was observed in 28 species followed by verrucate. Hence it can be said that pollen shape, polar, and equatorial diameters, pore size, P/E ratio, pore sculpturing are of good taxonomic value and holds a significant position in identification and delimitation of Poaceae taxa. [ABSTRACT FROM AUTHOR]

Climate change is driving abiotic shifts that can threaten the conservation of foundation species and the habitats they support. Directional range shifting is one mechanism of escape, but requires the successful colonization of habitats where interspecific interactions may differ from those to which a species has adapted. For plants with multiple reproductive strategies, these range‐edge interactions may alter the investment or allocation toward a given reproductive strategy. In this study, we quantified sexual reproduction of the clonal marsh grass Spartina patens across an inland colonization front into maritime forest being driven by sea‐level rise. We find that flowering is variable across S. patens meadows, but consistently reduced in low light conditions like those of the forest understory. Observational surveys of S. patens flowering at four sites in the Delmarva Peninsula agreed with the results of two experimental manipulations of light availability (shading experiment in S. patens‐dominated marsh and a forest dieback manipulation). These three approaches pinpointed light limitation as a principal control on S. patens flowering capacity, suggesting that light competition with taller upland species can suppress S. patens flowering along its upland migration front. Consequently, all propagation in shaded conditions must occur clonally or via seeds from the marsh, a reproductive restriction that could limit the potential for local adaptation and reduce genetic diversity. Future research is needed to determine whether the lack of flowering is the result of a trade‐off between sexual and clonal reproduction or results from insufficient photosynthetic products needed to achieve either reproductive method. [ABSTRACT FROM AUTHOR]

Micromorphology of 15 grass caryopsis was investigated through scanning electron microscopy for its implications in the identification of grasses. Both macro and micromorphological characters especially caryopsis shape and surface morphology were found significant in the taxonomic diagnosis. Shape morphology of caryopsis varied among the species and lanceolate, fusiform, narrow ellipsoidal, ovate, elliptical, plano‐convex, fusiform, linear ovate, broadly elliptical, broadly pllipsoidal, plano‐convex, oblique ovate, and subglobose shapes were recorded. Digitaria nodosa (3.31 × 0.7 mm) and Echinochloa crus‐galli (3.26 × 1.44 mm) had the largest caryopsis size, while Acrachne racemosa (0.76 × 0.54 mm) and Eragrostis minor (0.62 × 0.38 mm) had the smallest caryopsis size. Macro and micromorphological characters were useful for the diagnosis of genus and species. Utilizing both qualitative and quantitative character taxonomic key at generic and species level were made. [ABSTRACT FROM AUTHOR]