Plant Identity Research Articles

English

The objective of this study is to conduct an ethnobotanical survey of medicinal plants used in management of depression among Hausa tribes in order to establish an informational data base. An ethnobotanical survey was conducted in December 2015 in Zaria, Kaduna State, Nigeria. Data were collected based on an oral interview with the aid of semi structured questionnaire. Only data from willing respondents were obtained and documented. Plant specimens were collected along the line, they were subsequently dried and mounted. It was then taken for identification and authentication in the Herbarium Section of Biological Sciences, Ahmadu Bello University, Zaria where specimen voucher numbers were deposited. Information on sources, safety, methods of preparation and administrations, identity, local and botanical names of medicinal plants used in the management of depression among Hausa tribe of Kaduna State was obtained. An informational database was established and specimen with voucher numbers was deposited in the herbarium. Key words: Ethnobotanical survey, depression, botanical names, medicinal plants, safety.

A review of species recognition in the Phenacoccus aceris species-group (Hemiptera: Coccomorpha: Pseudococcidae) using molecular and morphological data

The maple mealybug, Phenacoccus aceris (Signoret) (Hemiptera: Pseudococcidae), is a widespread polyphagous pest. The taxonomy of P. aceris and some congeners is controversial. This study utilized molecular analysis of one mitochondrial (cytochrome oxidase I) and two nuclear (EF-1α and 28S D2D3) genes, and morphological data, to investigate the P. aceris species-group based on 120 individuals collected from 16 localities in China. Analyses of the nucleotide sequence data recovered four well-supported clades that enabled us to reassess the taxonomic utility of some morphological characters used for species recognition in the P. aceris species-group, such as the number, location and width of circuli, and the distribution pattern of oral-collar tubular ducts on the dorsum. Polymorphism in the number of circuli indicated that this character-state alone is unreliable for species separation, but a combination of the number, location and relative width of the circuli provides a significant taxonomic character. The distribution of oral-collar tubular ducts on dorsal segments of the cephalothorax can be used also for species separation. In addition, specimens that keyed morphologically to P. aceris contained three putative species that are not separated by host-plant preferences. These putative species are genetically and morphologically different from P. aceris in France (the type locality of P. aceris) and are thus probably new to science. A network analysis of the COI haplotypes showed that the hosts Fraxinus spp. (Oleaceae) and Zanthoxylum bungeanum (Rutaceae) in North China are attacked by both P. aceris and P. azaleae, so previous identifications of this group based on the identity of these host plants is misleading. The taxonomic confusion in the P. aceris species-group may be due to the co-occurrence of multiple putative species.

The role of macrophyte structural complexity and water flow velocity in determining the epiphytic macroinvertebrate community composition in a lowland stream

Habitat structural complexity provided by aquatic macrophytes in lowland streams affects the associated epiphytic macroinvertebrate assemblages in both direct (increased microhabitat diversity, refuge against predation) and indirect ways (e.g. current attenuation by physical structures). In a correlative field study carried out in two different years in a Belgian stream, we investigated the effects of the factors macrophyte identity, macrophyte complexity (represented as fractal complexity) and current velocity on the composition of the macroinvertebrate community associated with monospecific macrophyte patches, consisting of plants with differing structural complexity; Sparganium emersum Rehmann (least complex), Potamogeton natans L. (intermediate) and Callitriche obtusangula Le Gall (most complex). In addition to significantly lower within-patch current velocity being observed, vegetation stands consisting of complex macrophytes also harboured significantly richer macroinvertebrate communities than stands of simpler macrophytes. A significant part of the variation in the macroinvertebrate community composition could be explained by plant identity, macrophyte complexity and current velocity. However, it was not possible to determine the relative importance of these three factors, because of their high degree of intercorrelation. Additionally, the explanatory power of these factors was higher under conditions of high current velocity, suggesting a role of macrophyte patches as instream flow refugia for macroinvertebrates.

Cis and trans determinants of epigenetic silencing by Polycomb repressive complex 2 in Arabidopsis.

Disruption of gene silencing by Polycomb protein complexes leads to homeotic transformations and altered developmental-phase identity in plants. Here we define short genomic fragments, known as Polycomb response elements (PREs), that direct Polycomb repressive complex 2 (PRC2) placement at developmental genes regulated by silencing in Arabidopsis thaliana. We identify transcription factor families that bind to these PREs, colocalize with PRC2 on chromatin, physically interact with and recruit PRC2, and are required for PRC2-mediated gene silencing in vivo. Two of the cis sequence motifs enriched in the PREs are cognate binding sites for the identified transcription factors and are necessary and sufficient for PRE activity. Thus PRC2 recruitment in Arabidopsis relies in large part on binding of trans-acting factors to cis-localized DNA sequence motifs.

Phylogenetic and Functional Diversity of Fleshy-Fruited Plants Are Positively Associated with Seedling Diversity in a Tropical Montane Forest

Mutualistic interactions between plants and animals can affect both plant and animal communities, and potentially leave imprints on plant demography. Yet, no study has simultaneously tested how trait variation in plant resources shapes the diversity of animal consumers, and how these interactions influence seedling recruitment. Here, we analyzed whether i) phylogenetic diversity and functional diversity of fruiting plants were correlated with the corresponding diversity of frugivorous birds, and ii) whether phylogenetic diversity and functional identity of plant and bird communities influenced the corresponding diversity and identity of seedling communities. We recorded mutualistic interactions between fleshy-fruited plants and frugivorous birds and seedling communities in ten plots along an elevational gradient in the Colombian Andes. We built a phylogeny for plants/seedlings and birds and measured relevant morphological plant and bird traits that influence plant-bird interactions and seedling recruitment. We found that phylogenetic diversity and functional diversity of frugivorous birds were positively associated with the corresponding diversities of fruiting plants, consistent with a bottom-up effect of plants on birds. Moreover, the phylogenetic diversity of seedlings was related to the phylogenetic diversity of plants, but was unrelated to the phylogenetic diversity of frugivorous birds, suggesting that top-down effects of animals on seedlings were weak. Mean seed mass of seedling communities was positively associated with the mean fruit mass of plants, but was not associated with the mean avian body mass in the frugivore communities. Our study shows that variation in the traits of fleshy-fruited plants was associated with the diversity of frugivorous birds and affected the future trajectory of seedling recruitment, whereas the morphological traits of animal seed dispersers were unrelated to the phylogenetic and functional structure of seedling communities. These findings suggest that bottom-up effects are more important than top-down effects for seed-dispersal interactions and seedling recruitment in diverse tropical communities.

Declines in plant palatability from polar to tropical latitudes depend on herbivore and plant identity.

Long-standing theory predicts that the intensity of consumer-prey interactions declines with increasing latitude, yet for plant-herbivore interactions, latitudinal changes in herbivory rates and plant palatability have received variable support. The topic is of growing interest given that lower-latitude species are moving poleward at an accelerating rate due to climate change, and predicting local interactions will depend partly on whether latitudinal gradients occur in these critical biotic interactions. Here, we assayed the palatability of 50 seaweeds collected from polar (Antarctica), temperate (northeastern Pacific; California), and tropical (central Pacific; Fiji) locations to two herbivores native to the tropical and subtropical Atlantic, the generalist crab Mithraculus sculptus and sea urchin Echinometra lucunter. Red seaweeds (Rhodophyta) of polar and temperate origin were more readily consumed by urchins than were tropical reds. The decline in palatability with decreasing latitude is explained by shifts in tissue organic content along with the quantity and quality of secondary metabolites, degree of calcification or both. We detected no latitudinal shift in palatability of red seaweeds to crabs, nor any latitudinal shifts in palatability of brown seaweeds (Phaeophyta) to either crabs or urchins. Our results suggest that evolutionary pressure from tropical herbivores favored red seaweeds with lower palatability, either through the production of greater levels of chemical defenses, calcification, or both. Moreover, our results tentatively suggest that the "tropicalization" of temperate habitats is facilitated by the migration of tropical herbivores into temperate areas dominated by weakly defended and more nutritious foods, and that the removal of these competing seaweeds may facilitate the invasion of better-defended tropical seaweeds.

Petroleum Contamination and Plant Identity Influence Soil and Root Microbial Communities While AMF Spores Retrieved from the Same Plants Possess Markedly Different Communities.

Phytoremediation is a promising in situ green technology based on the use of plants to cleanup soils from organic and inorganic pollutants. Microbes, particularly bacteria and fungi, that closely interact with plant roots play key roles in phytoremediation processes. In polluted soils, the root-associated microbes contribute to alleviation of plant stress, improve nutrient uptake and may either degrade or sequester a large range of soil pollutants. Therefore, improving the efficiency of phytoremediation requires a thorough knowledge of the microbial diversity living in the rhizosphere and in close association with plant roots in both the surface and the endosphere. This study aims to assess fungal ITS and bacterial 16S rRNA gene diversity using high-throughput sequencing in rhizospheric soils and roots of three plant species (Solidago canadensis, Populus balsamifera, and Lycopus europaeus) growing spontaneously in three petroleum hydrocarbon polluted sedimentation basins. Microbial community structures of rhizospheric soils and roots were compared with those of microbes associated with arbuscular mycorrhizal fungal (AMF) spores to determine the links between the root and rhizosphere communities and those associated with AMF. Our results showed a difference in OTU richness and community structure composition between soils and roots for both bacteria and fungi. We found that petroleum hydrocarbon pollutant (PHP) concentrations have a significant effect on fungal and bacterial community structures in both soils and roots, whereas plant species identity showed a significant effect only on the roots for bacteria and fungi. Our results also showed that the community composition of bacteria and fungi in soil and roots varied from those associated with AMF spores harvested from the same plants. This let us to speculate that in petroleum hydrocarbon contaminated soils, AMF may release chemical compounds by which they recruit beneficial microbes to tolerate or degrade the PHPs present in the soil.

Selectivity and context dependence of Corsican red deer browsing in a Mediterranean coppice system

To manage potentially contrasting objectives such as ungulate conservation, habitat conservation, and forest harvesting, information about browsing patterns on vegetative regeneration of woody plants is needed. Here, we study browsing patterns of Corsican red deer on vegetative regeneration of coppices in a Mediterranean Holm oak forest. Within the forest management plan, the proportion of browsed shoots per plant was yearly monitored. Regression models were applied to estimate browsing probability of plants ( BrY ) and of shoots ( Br ), and evaluate factors though to affect red deer feeding behaviour, such as plant identity ( Sp ), plant height ( H ), years from coppicing ( Y fC ), density of palatable ( Dp ) and unpalatable plants ( Du ), and presence of wild boars ( WB ). Browsing rates were unrelated to relative abundance of species ( RA ), and strongly affected by Sp , suggesting high feeding selectivity of Corsican red deer. High browsing rates were observed on Quercus ilex ( RA =0.26; BrY =0.81, Br =0.41), and Phillyrea latifolia ( RA =0.07; BrY =0.89, Br =0.63). Early successional shrubs such as Arbutus unedo ( RA =0.39; BrY =0.04, Br =0.01), Erica arborea ( RA =0.14; BrY =0.06, Br =0.01), Cistus monspeliensis ( RA =0.08; BrY =0.05, Br =0.01), and Cistus salvifolius ( RA =0.05; BrY =0.10, Br =0.04), were very seldom browsed. Browsing probability of palatable species decreased with YfC and H , and was affected by Dp and Du . WB did not seem to affect browsing probability. The effect of plant density on browsing was explained in terms of relative palatability and associational resistance, which need to be considered in forest management plans of mixed forests under browsing pressure. To improve the biological understanding underlying forest management decisions, we recommend managers monitoring browsing impact on woody plants through space and time within plans of sustainable harvesting.

Can nutrient enrichment influence the invasion of Phragmites australis?

Plant invasion and nutrient enrichment because of anthropogenic landscape modifications seriously threaten native plant community diversity in aquatic and wetland ecosystems. It is poorly understood, however, whether these two disturbances interact with the functional identity of recipient native plants to drive community change. We performed combined studies in the fields and greenhouse to examine whether nutrient enrichment may trigger the invasion of Phragmites australis in wetlands through competitive advantage over native Melaleuca ericifolia. Chemical characterizations of rhizosphere water were distinguished in two different nutrient enriched wetlands associated with and without Phragmites over the seasons. Significant changes in rhizosphere water were observed in invaded area compared to uninvaded area at both sites. High nitrogen (NO3−), phosphorous (PO43−), dissolved organic carbon, phenolics contents, with low pH were found in invaded areas compared to uninvaded areas. Total biomass of Phragmites was positively regressed with rhizosphere water nitrogen (NO3−) and phosphorous (PO43−) content. Nutrient addition significantly enhanced the growth and competitive ability of Phragmites over Melaleuca. In contrast, Melaleuca was significantly less competitive than Phragmites. There was a significantly positive correlation between the growth of Phragmites grown alone and its competitive ability. The findings in greenhouse studies coupled with characteristics of Phragmites and its' rhizosphere chemistry in the nutrient enriched fields suggest that nutrient enrichment may enhance Phragmites invasion through correspondingly increasing growth and maintaining inherent competitive advantages of Phragmites. Nutrient management could limit the vigorous growth of Phragmites in wetlands and thereby reduce invasion through competitive advantages over natives, which might have important management implications for wetland managers.

Direct and indirect effects of climate, human disturbance and plant traits on avian functional diversity

AbstractAimClimate change and an increase in human disturbance are major drivers of global biodiversity loss. Yet it is not clear to what extent their effects on animal communities are direct or indirectly mediated by changes in biotic factors, such as plant diversity. Here, we disentangle the direct and indirect effects of climate, human disturbance, vegetation structure and plant functional traits on the functional diversity of avian frugivore communities across a large environmental gradient.LocationMount Kilimanjaro.Time periodSampling between November 2013 and October 2015.Major taxa studiedFleshy‐fruited plants, frugivorous birds.MethodsWe sampled plant and bird communities along an elevational and a human disturbance gradient and measured corresponding morphological traits of plants and birds to calculate indices of functional identity and functional diversity of plant and bird communities. We used structural equation models to disentangle direct and indirect effects of all variables on functional identity and diversity of frugivorous bird communities.ResultsBoth functional identity and diversity of frugivorous bird communities were consistently related to the functional identity and diversity of plant communities. Climate had almost exclusively indirect effects on functional identity and diversity of bird communities mediated through effects on plant functional identity and diversity. In contrast, human disturbance also had direct negative effects on bird diversity.Main conclusionsWe show that plant functional identity and diversity are the most important drivers of functional identity and diversity of frugivorous birds. Although effects of climate on bird communities are almost exclusively mediated indirectly through plant communities, human disturbance resulted in a direct reduction of bird diversity. The high degree of trait matching between interdependent trophic levels over a large environmental gradient demonstrates the importance of biotic drivers for animal communities and shows that biodiversity models need to consider such bottom‐up effects in future conditions.

Host plant and competitor identity matter in genotype × genotype × environment interactions between vetch and pea aphids

1. Selection does not only operate in a genotype (G) × environment (E) context, but can also be modulated by the activities of organisms interacting with their environment (G × G × E). 2. The influences of aphid clonal identity and host plant (Vicia faba) intraspecific genetic variation on the performance of five genotypes of pea aphid (Acyrthosiphon pisum) were investigated – with and without interaction with a competing heterospecific clone of vetch aphid (Megoura viciae) – across three cultivars of V. faba. 3. Pea aphid performance in the presence of a competing vetch aphid clone (G × G × E) compared with the absence of competition (G × E) revealed strong context-dependent, genotype-specific shifts in performance, influenced by plant cultivar, competitor presence and their interaction. 4. The performance of vetch aphid in competition with each pea aphid clone was also compared. Here, competitor's genotype and abundance underlay a remarkably varied response by vetch aphid across interactions. 5. The study shows that aphid genotypes exhibit a varying degree of risk spreading, contingent on competitor identity and the patterns of aggregation across three plant cultivars. Owing to feedback loops between species activities and selective forces acting on them, our findings suggest that there are context-dependent responses by competitors that are shaped via the interplay of the co-occurring species and their biotic environment. 6. This work highlights the complexity of species interactions and the importance of investigating reciprocity between competition and intraspecific genetic variation. A better understanding of the eco-evolutionary interactions between phloem-feeding insects and their host plants can potentially be used to enhance crop protection and pest control.

An empirical investigation of the possibility of adaptability of arbuscular mycorrhizal fungi to new hosts.

Little is known about the adaptive capacity of arbuscular mycorrhizal (AM) fungi to novel hosts. Here we assessed the possibility of two heterospecific AM fungal isolates to adaptively change, in terms of host biomass response, as a function of host plant identity, over the course of a growing season. First, we produced pure inocula of Rhizophagus clarus and Rhizophagus intraradices, each starting from a single spore. Second, we "trained" each isolate individually in a community with two plants, sudangrass (Sorgum bicolour subsp. drummondii) and leek (Aliium ampeloprasum var. porrum), using a dual-compartment system to allow the establishment of a common mycorrhizal network between the two hosts. Third, we conducted a greenhouse experiment to reciprocally test each "trained" clone, obtained from each compartment, either with the same (home), or the other host (away) under two contrasting phosphorus levels. Overall, results did not support adaptive responses of the AM fungi to their hosts (i.e., greater host biomass under "home" relative to "away" conditions), but the opposite (i.e., greater host biomass under "away" relative to "home" conditions) was more frequently observed. These changes in AM fungal symbiotic functioning open the possibility for relatively rapid genetic change of arbuscular mycorrhizal fungi in response to new hosts, which represents one step forward from in vitro experiments.

The effects of ant nests on soil fertility and plant performance: a meta‐analysis

Ants are recognized as one of the major sources of soil disturbance world-wide. However, this view is largely based on isolated studies and qualitative reviews. Here, for the first time, we quantitatively determined whether ant nests affect soil fertility and plant performance, and identified the possible sources of variation of these effects. Using Bayesian mixed-models meta-analysis, we tested the hypotheses that ant effects on soil fertility and plant performance depend on the substrate sampled, ant feeding type, latitude, habitat and the plant response variable measured. Ant nests showed higher nutrient and cation content than adjacent non-nest soil samples, but similar pH. Nutrient content was higher in ant refuse materials than in nest soils. The fertilizer effect of ant nests was also higher in dry habitats than in grasslands or savannas. Cation content was higher in nests of plant-feeding ants than in nests of omnivorous species, and lower in nests from agro-ecosystems than in nests from any other habitat. Plants showed higher green/root biomass and fitness on ant nests soils than in adjacent, non-nest sites; but plant density and diversity were unaffected by the presence of ant nests. Root growth was particularly higher in refuse materials than in ant nest soils, in leaf-cutting ant nests and in deserts habitats. Our results confirm the major role of ant nests in influencing soil fertility and vegetation patterns and provide information about the factors that mediate these effects. First, ant nests improve soil fertility mainly through the accumulation of refuse materials. Thus, different refuse dump locations (external or in underground nest chambers) could benefit different vegetation life-forms. Second, ant nests could increase plant diversity at larger spatial scales only if the identity of favoured plants changes along environmental gradients (i.e. enhancing β-diversity). Third, ant species that feed on plants play a relevant role fertilizing soils, which may balance their known influence as primary consumers. Fourth, the effects of ant nests as fertility islands are larger in arid lands, possibly because fertility is intrinsically lower in these habitats. Overall, this study provide novel and quantitative evidence confirming that ant nests are key soil modifiers, emphasizing their role as ecological engineers.

Agroecological and environmental factors influence Barley yellow dwarf viruses in grasslands in the US Pacific Northwest

Plant pathogens can play a role in the competitive interactions between plant species and have been understudied in native prairies, which are declining globally, and in Conservation Reserve Program (CRP) lands in the United States. Barley/Cereal yellow dwarf virus (B/CYDV) are among the most economically important disease-causing agents of small grain cereal crops, such as wheat, and are known to infect over 150 Poaceae species, including many of the grass species present in prairies and CRP lands. Field surveys of Poaceae species were conducted in endangered Palouse Prairie and CRP habitats of southeastern Washington and adjacent northern Idaho, USA from 2010 to 2012 to examine for the presence of B/CYDV among plant hosts and aphid vectors. Viral species were identified via cloning and sequencing. Landscape, soil and climate data were retrieved from USDA-NASS and USDA-NRCS databases. Analyses were conducted to examine effects of diverse agroecological and environmental factors on virus prevalence. A total of 2271 grass samples representing 30 species were collected; 28 of these were infected with BYDV in at least one location. BYDV infection was detected at every CRP and prairie remnant sampled, with an overall infection of 46%. BYDV-SGV and BYDV-PAV were the only two B/CYDV species encountered, with BYDV-SGV being more prevalent. Sampling time (season) and host plant identity were the main variables explaining variation in virus prevalence among sites. BYDV was more prevalent in perennial compared to annual grass species. Aphids were encountered only once suggesting non-colonizing aphids, potentially from neighboring cereal fields, are responsible for disease spread in these habitats. BYDV prevalence increased in sampled habitats as cereal crop cover increased within a 1-km radius of a habitat patch. Results demonstrate moderate to high and persistent prevalence of BYDV in an endangered grassland habitat. Species composition and susceptibility to pathogens should be considered when creating seed mixes for CRP sites, especially in relation to agricultural crops and diseases in a region. Future work exploring host abundance, competence and habitat utilization by vectors is required to fully elucidate BYDV ecology and epidemiology in grassland habitats.

Does leaf litter from invasive plants contribute the same support of a stream ecosystem function as native vegetation?

AbstractRiparian habitats are highly susceptible to invasion and the spread of non‐native plants. Many freshwater organisms and processes are dependent on allochthonous subsidies, and thus, riparian invasions are often associated with changes in aquatic ecosystems. We studied the potential effects of riparian plant invasions on instream decomposition and detritivore communities. We compared decomposition rates (k) of leaf litter from species native and invasive to coastal British Columbia, and the macroinvertebrate assemblages associated with the local and novel resource subsidy. Five native and five invasive species of riparian plants representing various growth forms (i.e., herbs, shrubs, and trees) were used in a litter bag experiment. Litter bags were distributed in stream‐side experimental channels, ensuring similarity in background environmental conditions (substrate, flow, and temperature). Compared to native litter, the k‐values of invasive plants were 2.6 times higher for herbs and 1.3 times higher for trees, while shrubs did not differ. Shrubs also decomposed significantly slower than trees and herbs. These patterns could be partially explained by the chemical properties of the litter. Throughout the whole experiment, decomposition rates were negatively related to the content of structural carbohydrates which tended to be higher in native leaves of herbs and shrubs. The k‐values also had positive relationships with nitrogen content measured in the unconditioned and conditioned litter, and invasive plant species had some of the highest values of leaf nitrogen. We found no significant relationships between decomposition rates and the lignin content of the conditioned and unconditioned leaf litter. Taxonomic richness of all aquatic macroinvertebrates and densities of all aquatic macroinvertebrates and shredders were significantly higher on the invasive litter incubated for 21 but not for 53 d. Finally, richness of shredders explained the highest proportion of the variance in decomposition rates, when compared to other biological (all macroinvertebrate densities and richness) and litter chemistry variables. Our results indicate that riparian plant invasions are associated with changes in aquatic litter decomposition; however, the direction of the change is largely dependent on litter quality and plant identity rather than growth form or exotic status.

Edible Insect Larvae in Kaytetye: Their Nomenclature and Significance

Insects have traditionally constituted an important source of food in many cultures, but changes in dietary practices and other lifestyle traits are threatening the transmission of insect-related knowledge and vocabulary to younger generations of Indigenous Australians. This paper describes the rich cultural and culinary traditions surrounding an important insect group, namely a class of edible insect larvae consumed by a desert community in central Australia. Twenty-nine different edible insect larvae are named in the Kaytetye language, with the names encoding the identity of the host plant on which the larvae are found. We describe the complexities involved in the naming system, paying special attention to cultural and linguistic factors. The difficulties in the scientific identification of these ethnotaxa are discussed, as are the significance of our data to (1) questions of universal patterns in ethnoclassification and nomenclature and (2) the purported lack of binomially-labeled folk species in the languages of hunter-gatherer societies.

Misapplied names, synonyms and new species of Ipomoea (Convolvulaceae) from South America

SummaryThe identities of plants treated under the names Ipomoea goyazensis Gardner, I. bignonioides Sims, I. patula Choisy, I. fiebrigii Hassl. ex O’Donell, I. hirsutissima Gardner and I. carajasensis D. F. Austin are evaluated. It is shown that the name I. goyazensis should be used for the cerrado species often known under the name I. decora Meisn., rather than a plant from southern Brazil which is here described as a new species I. austrobrasiliensis J. R. I. Wood & Scotland. I. bignonioides Sims is synonymised with I. mauritiana Jacq., and an epitype is selected to fix the application of this name and ensure it is not confused with I. goyazensis. I. patula is lectotypified and treated as a synonym of the African I. crassipes Hook. The different recognised varieties of I. patula are evaluated; var. monticola Meisn. is treated as a species under the name I. langsdorffii Choisy; var. villosa Meisn. is shown to be a synonym of I. guaranitica Chodat & Hassl., in which is included the little-known species I. cornucopia Chodat & Hassl. Specimens from Paraguay, originally also treated as I. patula var. villosa or I. malvaeoides Meisn. var. ovata Hallier f., are treated as a distinct species named I. cordillerae J. R. I. Wood & Scotland. Plants from Brazil treated in various herbaria under the name of the Paraguayan species I. fiebrigii are shown to be a distinct species, which is described as new under the name I. angustissima J. R. I. Wood & Scotland. Species sometimes included in I. hirsutissima are discussed and a key to distinguish them is provided. I. pyrenea Taub. is illustrated and shown to be distinct and a plant from Paraguay sometimes named I. hirsutissima is described as new under the name I. megalantha J. R. I. Wood & Scotland. I. carajasensis D. F. Austin is shown to be a synonym of I. maurandioides Meisn. and plants from the cerrados of central Brazil often identified as this species are described as new under the name I. aequiloba J. R. I. Wood & Scotland. Two other commonly misunderstood species I. elegans A. Dietr. and I. serpens Meisn. are also discussed. All new species and some little-known species are illustrated, maps of contrasting distributions are provided and various lectotypifications are made to fix the concepts of several species discussed in this paper.

Plant traits and plant biogeography control the biotic resistance provided by generalist herbivores

Summary Globalization and climate change trigger species invasions and range shifts, which reshuffle communities at an exceptional rate and expose plant migrants to unfamiliar herbivores. Dominant hypotheses to predict plant success are based on evolutionary novelty: either herbivores are maladapted to consume novel plants (enemy release hypothesis), or novel plants are maladapted to deter herbivores (biotic resistance hypothesis). Since novelty can work both ways, it fails to consistently predict when herbivores will consume novel over non‐novel plants. Surprisingly, the value of using plant traits to predict herbivore consumption of novel plants remains largely unexplored. We hypothesized that (i) plant traits explain generalist herbivore consumption rates of novel and non‐novel plants, and (ii) any effect of novelty will be grounded in consistent trait differences between native and novel plants. Lastly, we expected to find (iii) differences in plant traits and plant consumption rates across latitude. To test these hypotheses, we measured the consumption rate of plant species for a tropical and a temperate generalist herbivore in controlled feeding trials by offering them a large variety of 40 plant species from different geographical origins. Therefore, whether a plant was novel depended on the herbivore used, allowing us to disentangle plant identity from plant novelty. We also measured plant chemical traits and determined whether traits, geographical origin or novelty best explained herbivore consumption rates. Both generalist herbivores consumed more of plants with a high nitrogen‐to‐phenolic compounds ratio, irrespective of the plant's novelty to the herbivore. A pattern of increasing plant's nitrogen‐to‐phenolics ratio with latitude could explain why both the tropical and temperate herbivore consumed more of plants from temperate regions. Plant novelty and its geographical origin no longer explained consumption rates once differences in nitrogen‐to‐phenolic compounds ratio were taken into account. We show that differences in plant traits along a latitudinal cline determine herbivore consumption rates, irrespective of whether plants are novel or familiar. Therefore, we propose that integrating evolutionary novelty theory with plant traits and biogeography will increase our understanding of the consequences of plant species migration beyond biogeographical barriers. A lay summary is available for this article.

Functional characterization of a novel Brassica LEAFY homolog from Indian mustard: Expression pattern and gain-of-function studies

LEAFY plays a central role in regulation of flowering time and floral meristem identity in plants. Unfortunately, LFY function remains uncharacterized in agronomicaly important Brassicas. Herein, we illustrate fine-mapping of expression domains of LFY in 15 cultivars of 6 Brassica species and describe gain-of-function phenotypes in Arabidopsis and Brassica. We depict early flowering and altered fatty-acid composition in transgenic seed. The cDNA encoding BjuLFY (417aa) shared only 85% identity with reported homolog of B.juncea implying distinctness. Quantitative RT-PCR based coarse expression mapping of BjuLFY in tissue samples representing 3 time points at specific days after sowing (DAS), pre-flowering (30 DAS), flowering (75 DAS) and post-flowering (110 DAS), depicted an intense pulse of BjuLFY expression restricted to primary floral buds (75 DAS) which subsided in secondary floral buds (110 DAS); expression in root samples was also recorded implying neo-functionalization. Fine-mapping of expression during flowering confirmed tightly regulated LFY expression during early stages of bud development in 15 cultivars of 6 Brassica species implying functional conservation. Ectopic expression of BjuLFY in A. thaliana and B. juncea caused floral meristem defects and precocious flowering. B. juncea transgenics (T1) over-expressing BjuLFY flowered 20days earlier produced normal flowers. GC–MS analysis of mature seed from Brassica transgenics showed an altered fatty-acid profile suggestive of seed maturation occurring at lower temperatures vis-à-vis control. Our findings implicate BjuLFY as a regulator of flowering in B. juncea and suggest its application in developing climate resilient crops.

Effect of plant diversity on the diversity of soil organic compounds.

The effect of plant diversity on aboveground organisms and processes was largely studied but there is still a lack of knowledge regarding the link between plant diversity and soil characteristics. Here, we analyzed the effect of plant identity and diversity on the diversity of extractible soil organic compounds (ESOC) using 87 experimental grassland plots with different levels of plant diversity and based on a pool of over 50 plant species. Two pools of low molecular weight organic compounds, LMW1 and LMW2, were characterized by GC-MS and HPLC-DAD, respectively. These pools include specific organic acids, fatty acids and phenolics, with more organic acids in LMW1 and more phenolics in LMW2. Plant effect on the diversity of LMW1 and LMW2 compounds was strong and weak, respectively. LMW1 richness observed for bare soil was lower than that observed for all planted soils; and the richness of these soil compounds increased twofold when dominant plant species richness increased from 1 to 6. Comparing the richness of LMW1 compounds observed for a range of plant mixtures and for plant monocultures of species present in these mixtures, we showed that plant species richness increases the richness of these ESOC mainly through complementarity effects among plant species associated with contrasted spectra of soil compounds. This could explain previously reported effects of plant diversity on the diversity of soil heterotrophic microorganisms.