Terrestrial Plant Species Research Articles

Evaluating the ecotoxicity of nitrification inhibitors using terrestrial and aquatic test organisms

BackgroundThe increasing demand for food and animal fodder worldwide has led to an intensified agriculture with an increasing use of nitrogen fertilizers. More recently, nitrate leaching and gaseous nitrogen emissions have become the focus of environmental discussions and climate politics. One approach to reduce such negative impacts is the use of nitrification inhibitors (NIs) that have shown to effectively reduce nitrogen losses to the groundwater and the air. However, ecotoxic effects of NIs have been studied to a limited extent only. Therefore, two commercial NIs (Piadin and Vizura) and an active ingredient of another NI, dicyandiamide (DCD), were assayed using various ecotoxicological biotests and test species: the Lemna Growth Inhibition Test (Lemna gibba), the Seed Germination/Root Elongation Toxicity Test (Agrostemma githago, Fagopyrum esculentum, Glycine max, Hordeum vulgare, Lunaria annua, Zea mays), the Seedling Emergence and Seedling Growth Test (A. githago, F. esculentum, Z. mays) and the marine Luminescent Bacteria Test (Aliivibrio fischeri). The fresh water L. gibba and the bacterium A. fischeri were exposed to different test concentrations in liquid growth media, whereas the terrestrial plants were exposed to the test substances diluted/dissolved in deionized water and added to the solid growth medium.ResultsDicyandiamide did not show ecotoxic effects in any test conducted. Piadin and Vizura showed ecotoxic effects throughout all experiments. Frond number and frond area of L. gibba were inhibited with increasing concentrations of both substances with Piadin leading to an earlier inhibition and therefore lower EC50 values. In the Seed Germination Test, Vizura generally inhibited seed germination and root development more effectively than Piadin. Regarding both substances, the endpoint root length was much more sensitive than the endpoint germination. In the Seedling Emergence Test, Z. mays was the least sensitive and the rare weed species A. githago the most sensitive species with regard to the tested endpoints and both substances. A. fischeri was strongly inhibited by Vizura, whereas Piadin had barely effects on the bacteria.ConclusionAll findings indicate ecotoxic effects of Piadin and Vizura, especially on the aquatic species L. gibba and on the root development of several terrestrial plant species. However, the origins of the ecotoxic properties remain unclear as both substances contain a mixture of—to some extent unknown—chemical compounds.

Whole-genome resequencing identifies quantitative trait loci associated with mycorrhizal colonization of soybean.

A whole-genome resequencing-derived SNP dataset identified six quantitative trait loci (QTL) significantly associated with colonization of soybean by an arbuscular mycorrhizal fungus (Rhizophagus intraradices). Candidate genes identified in these QTL regions include homologs to known nodulin protein families and other symbiosis-specific genes. Arbuscular mycorrhizal fungi (AMF) form associations with over 80% of all terrestrial plant species and assist their host plants by increasing their nutrient uptake, drought tolerance, and resilience against pathogens and pests. Genotypic variation of crop plants to AMF colonization has been identified in crops, including soybean; however, the genetics controlling levels of AMF colonization in soybean are unknown. The overall goal of our study was to identify genomic regions associated with mycorrhizal colonization in soybean using genome-wide association analysis. A diverse panel of 350 exotic soybean genotypes inoculated with Rhizophagus intraradices were microscopically evaluated for root colonization using a modified gridline intersect method. Root colonization differed significantly (P < 0.001) among genotypes and ranged from 11 to 70%. A whole-genome resequencing-derived SNP dataset identified six quantitative trait loci (QTL) significantly associated with R. intraradices colonization that explained 24% of the phenotypic variance. Candidate genes identified in these QTL regions include homologs to known nodulin protein families and other symbiosis-specific genes. The results showed there was a significant genetic component to the level of colonization by R. intraradices in soybean. This information may be useful in the development of AMF-sensitive soybean cultivars to enhance nutrient uptake, drought tolerance, and disease resistance in the crop.

Precipitation δ18O Recorded by the α‐Cellulose δ18O of Plant Residues in Surface Soils: Evidence From a Broad Environmental Gradient in Inland China

AbstractIn order to determine the potential of α‐cellulose δ18O (δ18Ocell) data from multiple terrestrial plant species on an ecosystem level to record the δ18O data of precipitation (δ18Op), especially in relatively cold and arid environments, we collected samples of terrestrial plant residues from 104 surface soils covering a large environmental gradient (~29 to 51°N in latitude, ~81 to 124°E in longitude, ~200 to 5,100 m in elevation) in inland China. Despite the diverse vegetation types, wide range of climatic conditions and potentially complex biogeochemical processes operating within the vast study region, the δ18Ocell data show a similar spatial pattern to that of δ18Op. The results demonstrate that the measured values of δ18Ocell data have the potential to record variations in δ18Op. Further analysis indicated that the δ18Ocell data from the Tibetan Plateau were primarily controlled by the moisture sources. Interestingly, there are significant negative correlations between δ18Ocell/δ18Op and altitude on the Tibetan Plateau, implying the potential of δ18Ocell for paleoaltimetry in this region. The δ18Ocell data from the northern region of China (including the East Asian monsoon‐margin and arid central Asia) were mainly controlled by temperature, although the influence of relative humidity in the region is not negligible. Our results provide a fundamental reference for related δ18Ocell studies aimed to improve our understanding of environmental, hydrological, and climatic changes in inland China and elsewhere.

A Review of the Flora and Fauna in the Al Wathba Wetland Reserve in Abu Dhabi, United Arab Emirates

Wetlands play an important role in ecosystem function, and are known to support rich biodiversity, this becomes even more pronounced in hyper-arid climates. The Al Wathba Wetland Reserve in Abu Dhabi Emirate is a wetland mosaic that boasts both brackish and freshwater pools. The levels of nitrate, nitrite, phosphate and total organic carbon is much higher and this can be attributed to various factors such as the lake not having a water outlet, seepage of untreated waste water from an adjacent sewage treatment plant and various industries in the surrounding areas that could lead to these high values. A twenty-year biodiversity assessment and monitoring program, has documented a total of 354 invertebrate species, 16 reptile and amphibian species, 262 bird species, 10 mammalian species, and 39 plant species. These represent 21% of Abu Dhabi Emirate’s terrestrial animal and plant species. Out of a total of 44 marine and terrestrial habitats identified within Abu Dhabi Emirate, 6 of these are represented within AWWR.

Evaluating the ecological realism of plant species distribution models with ecological indicator values

Species distribution models (SDMs) are routinely applied to assess current as well as future species distributions, for example to assess impacts of future environmental change on biodiversity or to underpin conservation planning. It has been repeatedly emphasized that SDMs should be evaluated based not only on their goodness of fit to the data, but also on the realism of the modeled ecological responses. However, possibilities for the latter are hampered by limited knowledge on the true responses as well as a lack of quantitative evaluation methods. Here we compared modeled niche optima obtained from European‐scale SDMs of 1476 terrestrial vascular plant species with empirical ecological indicator values indicating the preferences of plant species for key environmental conditions. For each plant species we first fitted an ensemble SDM including three modeling techniques (GLM, GAM and BRT) and extracted niche optima for climate, soil, land use and nitrogen deposition variables with a large explanatory power for the occurrence of that species. We then compared these SDM‐derived niche optima with the ecological indicator values by means of bivariate correlation analysis. We found weak to moderate correlations in the expected direction between the SDM‐derived niche optima and ecological indicator values. The strongest correlation occurred between the modeled optima for growing degree days and the ecological indicator values for temperature. Correlations were weaker for SDM‐derived niche optima with a more distal relationship to ecological indicator values (notably precipitation and soil moisture). Further, correlations were consistently highest for BRT, followed by GLM and GAM. Our method gives insight into the ecological realism of modeled niche optima and projected core habitats and can be used to improve SDMs by making a more informed selection of environmental variables and modeling techniques.

In vivo evidence for a regulatory role of phosphorylation of Arabidopsis Rubisco activase at the Thr78 site

Arabidopsis Rubisco activase (Rca) is phosphorylated at threonine-78 (Thr78) in low light and in the dark, suggesting a potential regulatory role in photosynthesis, but this has not been directly tested. To do so, we transformed an rca-knockdown mutant largely lacking redox regulation with wild-type Rca-β or Rca-β with Thr78-to-Ala (T78A) or Thr78-to-Ser (T78S) site-directed mutations. Interestingly, the T78S mutant was hyperphosphorylated at the Ser78 site relative to Thr78 of the Rca-β wild-type control, as evidenced by immunoblotting with custom antibodies and quantitative mass spectrometry. Moreover, plants expressing the T78S mutation had reduced photosynthesis and quantum efficiency of photosystem II (ϕPSII) and reduced growth relative to control plants expressing wild-type Rca-β under all conditions tested. Gene expression was also altered in a manner consistent with reduced growth. In contrast, plants expressing Rca-β with the phospho-null T78A mutation had faster photosynthetic induction kinetics and increased ϕPSII relative to Rca-β controls. While expression of the wild-type Rca-β or the T78A mutant fully rescued the slow-growth phenotype of the rca-knockdown mutant grown in a square-wave light regime, the T78A mutants grew faster than the Rca-β control plants at low light (30 µmol photons m-2 s-1) and in a fluctuating low-light/high-light environment. Collectively, these results suggest that phosphorylation of Thr78 (or Ser78 in the T78S mutant) plays a negative regulatory role in vivo and provides an explanation for the absence of Ser at position 78 in terrestrial plant species.

The scaling of fine root nitrogen versus phosphorus in terrestrial plants: A global synthesis

AbstractLeaves and roots may differ in nitrogen (N), phosphorus (P) and N:P stoichiometry, which can influence plant growth and ecosystem functioning. As compared to leaves, however, relatively little is known about the N versus P scaling relationship and N:P stoichiometry in root systems, particularly in fine roots.We used a global dataset comprising 1,890 observations for a total of 763 terrestrial plant species in 123 families (spanning 433 sites world‐wide) to examine live fine root N and P concentrations and stoichiometry, and to determine the scaling of N versus P within and across different plant groups and ecosystems.The global geometric mean values of fine root N and P concentrations and N:P ratios were 10.84 mg/g, 0.94 mg/g and 11.55, respectively. Fine root N and P concentrations and N:P ratios varied both within and across plant groups and ecosystems. A 0.82‐power law described the scaling of fine root N with respect to P across the entire dataset and for major plant phylogenetic and functional groups; however, the numerical value of the N versus P scaling exponent declined from the tropics to higher latitudes and varied significantly at different local sites. Soil nutrient account for much of the variation observed in the scaling of fine root N versus P concentration at different local sites.This study advances our knowledge about limiting resource allocation strategies in below‐ground organs and has important implications for modelling plant growth at local, regional and global levels.A freePlain Language Summarycan be found within the Supporting Information of this article.

Impacts of long-term elevated atmospheric CO2 concentrations on communities of arbuscular mycorrhizal fungi.

The ecological impacts of long‐term elevated atmospheric CO2 (eCO2) levels on soil microbiota remain largely unknown. This is particularly true for the arbuscular mycorrhizal (AM) fungi, which form mutualistic associations with over two‐thirds of terrestrial plant species and are entirely dependent on their plant hosts for carbon. Here, we use high‐resolution amplicon sequencing (Illumina, HiSeq) to quantify the response of AM fungal communities to the longest running (>15 years) free‐air carbon dioxide enrichment (FACE) experiment in the Northern Hemisphere (GiFACE); providing the first evaluation of these responses from old‐growth (>100 years) semi‐natural grasslands subjected to a 20% increase in atmospheric CO2. eCO2 significantly increased AM fungal richness but had a less‐pronounced impact on the composition of their communities. However, while broader changes in community composition were not observed, more subtle responses of specific AM fungal taxa were with populations both increasing and decreasing in abundance in response to eCO2. Most population‐level responses to eCO2 were not consistent through time, with a significant interaction between sampling time and eCO2 treatment being observed. This suggests that the temporal dynamics of AM fungal populations may be disturbed by anthropogenic stressors. As AM fungi are functionally differentiated, with different taxa providing different benefits to host plants, changes in population densities in response to eCO2 may significantly impact terrestrial plant communities and their productivity. Thus, predictions regarding future terrestrial ecosystems must consider changes both aboveground and belowground, but avoid relying on broad‐scale community‐level responses of soil microbes observed on single occasions.

Analyzing airborne environmental DNA: A comparison of extraction methods, primer type, and trap type on the ability to detect airborne eDNA from terrestrial plant communities

AbstractAirborne environmental DNA (eDNA) research has typically focused on the detection of pollen from anemophilous terrestrial plant species; however, recent findings have expanded the definition of airborne eDNA to include a variety of eDNA sources, such as leaf and flower fragments. While methods for capturing pollen are well studied, there is less known about how to best analyze and capture more broadly defined bulk airborne eDNA samples. Therefore, this study aimed to identify efficient techniques for the extraction and amplification of airborne eDNA and how best to capture these samples. First, we collected samples using Big Spring Number Eight dust traps and quantified the influence of three different extraction methods (cetrimonium bromide‐chloroform, DNeasy Plant Maxi Kit, and DNeasy PowerPlant Pro DNA Isolation Kit) and two global plant primer sets (targeting the trnL and ITS2 genes) on quantitative polymerase chain reaction (qPCR)‐based terrestrial plant detection. Additionally, we examined how best to capture airborne eDNA by comparing the performance of three difference passive dust collectors (Big Spring Number Eight, Modified Wilson and Cooke, and Marble dust collectors). We found that the detection of airborne eDNA was significantly influenced by both the extraction methods employed and choice of qPCR primer. Additionally, we found that all three traps preformed similarly but the Big Spring Number Eight dust traps trended as consistently one of the most effective, shedding light on the nonhomogeneous nature of airborne eDNA. This study represents the first methodology paper focusing on airborne eDNA as a bulk environmental sample containing more than just pollen. In the future, additional research should examine more about the ecology of airborne eDNA (origin, state, transport, fate), explore active dust collectors compared to the passive traps used here, and develop the application of metabarcoding for airborne eDNA analysis.

Geese are overlooked dispersal vectors for vascular plants in archipelago environments

AbstractQuestionWe addressed the importance of gut‐mediated dispersal by greylag geese for vascular plants in archipelago environments and asked: (a) What proportion of the local species pool is dispersed by geese? (b) Which plant traits characterize species dispersed by geese? (c) Which plant communities are likely to benefit from endozoochory by geese?LocationThree Swedish Baltic archipelagos.MethodsGoose droppings were collected on 45 islands. Plants germinating from the droppings represent the endozoochorous species pool (ESP). On 108 islands, the presence of vascular plants was recorded in each habitat. These species represent the island species pool (ISP). Differences in functional traits between ESP and ISP were expressed as effect sizes and tested using meta‐regressions. Using indicator species analyses and indicator species for managed semi‐natural grasslands, we identified the primary habitats of the ESP.ResultsGeese dispersed viable diaspores of 97 plant species, which represents 22% of the ISP. Most ESP species were typical for small islands. Geese dispersed a higher proportion of graminoids and less woody plants, higher proportions of chamaephytes and therophytes and less phanerophytes; annuals and bi‐annuals were significantly overrepresented. On average, seed volume of the ESP was 95% smaller than that of the ISP. About 51% of all ESP species were dispersed in at least two archipelagos. Geese showed a bias towards species of rocky shore habitats.ConclusionGeese potentially disperse large amounts of diaspores of many terrestrial island plant species. Through their feeding behaviour, geese select species with certain suites of traits from the regional species pool. Plant dispersal by geese may benefit plants species of rocky shores, but species of formerly managed semi‐natural grasslands may also find refuge sites on epilittoral shores after goose‐mediated dispersal. The relative importance of geese as dispersal vectors may increase under on‐going land‐use changes and cessation of grazing networks.

An ecological perspective on 'plant carnivory beyond bogs': nutritional benefits of prey capture for the Mediterranean carnivorous plant Drosophyllum lusitanicum.

Little is known about the evolutionary and ecological drivers of carnivory in plants, particularly for those terrestrial species that do not occur in typical swamp or bog habitats. The Mediterranean endemic Drosophyllum lusitanicum (Drosophyllaceae) is one of very few terrestrial carnivorous plant species outside of Australia to occur in seasonally dry, fire-prone habitats, and is thus an ecological rarity. Here we assess the nutritional benefits of prey capture for D. lusitanicum under differing levels of soil fertility in situ. We measured the total nitrogen and stable nitrogen and carbon isotope ratios of D. lusitanicum leaves, neighbouring non-carnivorous plant leaves, and groups of insect prey in three populations in southern Spain. We calculated trophic enrichment (ε15N) and estimated the proportion of prey-derived nitrogen (%Nprey) in D. lusitanicum leaves, and related these factors to soil chemistry parameters measured at each site. In all three populations studied, D. lusitanicum plants were significantly isotopically enriched compared with neighbouring non-carnivorous plants. We estimated that D. lusitanicum gain ~36 %Nprey at the Puerto de Gáliz site, ~54 %Nprey at the Sierra Carbonera site and ~75 %Nprey at the Montera del Torero site. Enrichment in N isotope (ε15N) differed considerably among sites; however, it was not found to be significantly related to log10(soil N), log10(soil P) or log10(soil K). Drosophyllum lusitanicum individuals gain a significant nutritional benefit from captured prey in their natural habitat, exhibiting proportions of prey-derived nitrogen that are similar to those recorded for carnivorous plants occurring in more mesic environments. This study adds to the growing body of literature confirming that carnivory is a highly beneficial nutritional strategy not only in mesic habitats but also in seasonally dry environments, and provides insights to inform conservation strategies for D. lusitanicum in situ.

Effects of endophyte infection on the competitive ability of Achnatherum sibiricum depend on endophyte species and nitrogen availability

Abstract Aims The leaves of almost all terrestrial plant species are colonized by endophytic fungi. Compared to agronomic grasses, which usually harbor few endophytes, native grasses generally possess greater endophyte species diversity. Existing studies examining endophyte effects on natural grasses under competition normally considered the infection status (infected or uninfected), and rarely considered endophyte species. Methods We examined the effects of endophyte infection and of endophyte species on the interspecific competitive ability of a subdominant species, Achnatherum sibiricum, at two nitrogen levels (high nitrogen and low nitrogen). Achnatherum sibiricum plants infected by two different species of endophyte (Epichloë sibirica and E. gansuensis) and uninfected plants were grown in monoculture and binary mixtures with a dominant species, Stipa grandis (six individuals per species for monocultures and three + three individuals of each species in mixtures). Shoot and root biomass, tiller number and total phenolic concentration were measured after 3 months. Moreover, the aggressivity index was calculated to compare the competitive ability of A. sibiricum relative to S. grandis. Important Findings Both E. gansuensis (Eg)- and E. sibirica (Es)-infected A. sibiricum plants showed a greater competitive ability than the uninfected plants under high nitrogen supply, while the opposite result occurred under low nitrogen supply. At high nitrogen levels, Eg plants had a higher tiller number and a greater shoot biomass inhibitory effect on S. grandis than Es plants had when growing in mixture, while Es plants showed better root growth performance than Eg and uninfected plants under mixture conditions at all nitrogen levels. A higher concentration of phenolic compounds in Eg plants than in Es plants might contribute to the higher inhibitory effect of Eg plants on competing plants. Our study indicates that the interaction between endophyte infection and nitrogen availability can alter the competitive ability of the host plant A. sibiricum but that these two endophyte species work in different ways, which may influence the coexistence of A. sibiricum with the dominant species.

Metabolite profiles reveal interspecific variation in operation of the Calvin-Benson cycle in both C4 and C3 plants.

Low atmospheric CO2 in recent geological time led to the evolution of carbon-concentrating mechanisms (CCMs) such as C4 photosynthesis in >65 terrestrial plant lineages. We know little about the impact of low CO2 on the Calvin-Benson cycle (CBC) in C3 species that did not evolve CCMs, representing >90% of terrestrial plant species. Metabolite profiling provides a top-down strategy to investigate the operational balance in a pathway. We profiled CBC intermediates in a panel of C4 (Zea mays, Setaria viridis, Flaveria bidentis, and F. trinervia) and C3 species (Oryza sativa, Triticium aestivum, Arabidopsis thaliana, Nicotiana tabacum, and Manihot esculenta). Principal component analysis revealed differences between C4 and C3 species that were driven by many metabolites, including lower ribulose 1,5-bisphosphate in C4 species. Strikingly, there was also considerable variation between C3 species. This was partly due to different chlorophyll and protein contents, but mainly to differences in relative levels of metabolites. Correlation analysis indicated that one contributory factor was the balance between fructose-1,6-bisphosphatase, sedoheptulose-1,7-bisphosphatase, phosphoribulokinase, and Rubisco. Our results point to the CBC having experienced different evolutionary trajectories in C3 species since the ancestors of modern plant lineages diverged. They underline the need to understand CBC operation in a wide range of species.

Comparative assessment of the intrinsic sensitivity of crop species and wild plant species to plant protection products and their active substances and potential implications for the risk assessment: A literature review.

A comprehensive critical review was undertaken aiming to compare the intrinsic sensitivity of terrestrial plant species (crop species and noncrop wild species) with published literature and unpublished proprietary data generated for the registration of plant protection products (PPPs), and a database was compiled. Data were assessed to answer the question whether crops differ from noncrop plants in their intrinsic sensitivity to PPPs. Endpoints were assessed considering further potentially relevant parameters by means of different methods, including a quotient approach, in which overall crop endpoints were divided by matching wild species endpoints. Quotients above 1 indicated that wild species were more sensitive than crops, quotients below 1 the opposite. Further methods included a multiple regression analysis and different approaches to assess the statistical power. The overall finding was that there were no consistent differences in sensitivity between wild plant species and crop species, based on ER50, ER25, and ER10 vegetative endpoints (the largest fraction of data). This was also true when censored endpoints, seedling emergence data, and other measured variables such as shoot height were included. Statistically significant differences occurred in both directions and were balanced, that is, there was no clear trend for either crops or noncrop species to be more sensitive than the other. On the basis of multivariate regression analysis, crops were found to be significantly more sensitive than wild plant species, albeit by a small margin (factor ≈1.4). Minimum detectable difference (MDD) analysis and multivariate regression analysis of modified datasets indicated that when using a data set of this size and heterogeneity, any dissimilarity between crop and wild species was detectable if exceeding a factor of 1.4 in either direction. For the taxonomic groups assessed here (i.e., with data), no intrinsic difference in sensitivity to PPPs between crop species and wild plant species was found. Integr Environ Assess Manag 2019;15:176-189. © 2018 SETAC.

Achene traits involved in the water dispersal of the invasive Fallopia × bohemica complex: Variability and dispersal strategies

Secondary dispersal of terrestrial plant species through watercourses increases the dispersal range of floating seeds but their exposure to water may also challenge their viability and colonisation potential. Many terrestrial invasive species benefit from watercourses to extend their invasive range because water exposure can favour seed germination and early survival of seedlings for species sensitive to dry conditions and water flow enhances their dispersal distance downstream. Floatability, germination rate and survival after water exposure are seed traits involved in water dispersal and their variability may lead to different dispersal strategies. To address the question of the variability of achene traits involved in dispersal, we experimentally measured these three traits for Fallopia × bohemica achenes collected from 10 different stands. The floatability of achenes varied between stands from 2.5 to 5 days and their germination in water extended this period to 20 days through the emergence of floating seedlings. Germination proportions also differed between stands from 0.3 to 0.95 and were negatively related to the median germination time. Seedling survival after planting in soil was affected by their exposure time. This effect differed between stands, but a short germination time did not explain a better survival of some stands. These results show that achenes may differ in their dispersal potential in terms of floatability, as well as tolerance of seedlings to water exposure during dispersal. This study also highlights the fact that achenes of some stands present a combination of traits particularly adapted to long distance dispersal through watercourses, which can contribute to the extension of the invaded area.

Late Quaternary Aboriginal hunter-gatherer occupation of the Greater Swan Region, south-western Australia

The Greater Swan Region is an archaeological study area on the Indian Ocean coast in south-western Australia. It covers the central Swan Coastal Plain and the adjacent part of the formerly emergent Rottnest Shelf. Assessment of Aboriginal hunter-gatherer activity throughout this late Quaternary coastal landscape is based on dated records of open-air sites within their environmental settings, informed by historical accounts of mainland subsistence activities. Artefacts flaked from Eocene fossiliferous chert and other stone, identified, in situ, in dated dune soils on the mainland and in palaeosols and Tamala Limestone successions on Rottnest Island, show that during regressive sea levels human groups were distributed across a sand plain reaching from the Darling Scarp 70 km westward across the emergent Rottnest Shelf. On the mainland, open-air site settings near freshwater sources and terrestrial and estuarine habitats give insight into adaptive strategies of Aboriginal occupiers. A similar occupation pattern is proposed for the emergent shelf. Early Holocene records of terrestrial plant species and freshwater microfauna from Barker Swamp on Rottnest Island imply that freshwater sources and terrestrial habitats were comparable to those of the mainland. Further archaeological investigations on the Rottnest Shelf should include extant and former freshwater swamps on Rottnest Island.

Terrestrial Plants Evolve Highly Assembled Photosystem Complexes in Adaptation to Light Shifts.

It has been known that PSI and PSII supercomplexes are involved in the linear and cyclic electron transfer, dynamics of light capture, and the repair cycle of PSII under environmental stresses. However, evolutions of photosystem (PS) complexes from evolutionarily divergent species are largely unknown. Here, we improved the blue native polyacrylamide gel electrophoresis (BN-PAGE) separation method and successfully separated PS complexes from all terrestrial plants. It is well known that reversible D1 protein phosphorylation is an important protective mechanism against oxidative damages to chloroplasts through the PSII photoinhibition-repair cycle. The results indicate that antibody-detectable phosphorylation of D1 protein is the latest event in the evolution of PS protein phosphorylation and occurs exclusively in seed plants. Compared to angiosperms, other terrestrial plant species presented much lower contents of PS supercomplexes. The amount of light-harvesting complexes II (LHCII) trimers was higher than that of LHCII monomers in angiosperms, whereas it was opposite in gymnosperms, pteridophytes, and bryophytes. LHCII assembly may be one of the evolutionary characteristics of vascular plants. In vivo chloroplast fluorescence measurements indicated that lower plants (bryophytes especially) showed slower changes in state transition and nonphotochemical quenching (NPQ) in response to light shifts. Therefore, the evolution of PS supercomplexes may be correlated with their acclimations to environments.

Brazilian efforts towards achieving a comprehensive extinction risk assessment for its known flora

Abstract Brazil houses nearly 36,400 native terrestrial plant species. The country is a signatory of the Global Strategy for Plant Conservation (GSPC) and has to develop tools to achieve GSPC targets. Target 2 states that countries must undertake risk assessments of its entire known plant species by 2020. Here, we offer a panorama on how far has Brazil gone towards achieving this target. We compiled data on all risk assessments for plant species ever made in the country and produced the first synthesis of results with respect to these assessments. We found that the Brazilian Red List Authority for plants has assessed the extinction risk of 5,646 species so far, which corresponds to 15.5% of all known flora in Brazil. Among these species, 2,738 (48%) are currently threatened. Those species are distributed across all Brazilian Biomes and states. Families with the highest number of threatened species are Asteraceae and Bromeliaceae. We conclude that Brazil is far from achieving GSPC target 2 by 2020. However, given the enormous flora of the country and the huge amount of effort and resources put into this particular task, Brazil is following a good path towards a reliable assessment of it entire flora.

Effect factors of terrestrial acidification in Brazil for use in Life Cycle Impact Assessment

In Life Cycle Impact Assessment, atmospheric fate factors, soil exposure factors, and effect factors are combined to characterize potential impacts of acidifying substances in terrestrial environments. Due to the low availability of global data sets, effect factors (EFs) have been reported as the major contributors to statistical uncertainties of characterization factors and they are the focus of this study. We aim to develop spatially differentiated EFs taking Brazil as case and explore new methodological ways to derive them. EFs are calculated based on a comprehensive database reporting observations of approximately 30,000 plant species at biome and ecoregion levels. Species richness distributions as function of soil pH are developed and translated into potentially not occurring fraction (PNOF) of species, which can be equated to the more commonly used potentially disappeared fraction of species, to assess effects of changes in soil hydrogen ion concentration on terrestrial plant species. Potentially extinct fraction (PXF) of species is proposed as a complementary metric for LCIA models based on distributions of range-restricted species (species only occurring in one ecoregion of Brazil). Different approaches for determining EFs from the species richness distributions are evaluated. Area-weighted EFs are explored to determine potential effects when considering both acid and alkaline sides of species richness curves, thus integrating potentially positive effects of acidification on biodiversity. Spatially differentiated EFs are provided for 6 biomes and 45 ecoregions composing Brazil. Comparisons with previous EFs demonstrate that data availability might significantly influence regression analyses, and the use of more representative data can lead to more consistent EFs. Moreover, consideration of the entire species richness curves yields positive and negative EFs. Adding acidifying substances onto specific soils in Brazilian ecoregions may therefore be associated with increased species richness if the pH approaches the optimum pH from the alkaline side of the curve. The meaningfulness of species richness as indicator of acidification stress is discussed based on this finding, as is the inclusion of the metric PXF, highlighting species whose loss could cause irreversible damages to the environment. We recommend the calculation of area-weighted EFs to be integrated into characterization models for terrestrial acidification, and we therefore advocate that similar work be done for other regions in the world than Brazil to enhance the consistency of the EFs and reduce their uncertainties. We additionally recommend that LCIA method developers further explore the application of PXF for other impact categories than acidification.

Impact of Beneficial Microorganisms on Strawberry Growth, Fruit Production, Nutritional Quality, and Volatilome.

Arbuscular mycorrhizal fungi (AMF) colonize the roots of most terrestrial plant species, improving plant growth, nutrient uptake and biotic/abiotic stress resistance and tolerance. Similarly, plant growth promoting bacteria (PGPB) enhance plant fitness and production. In this study, three different AMF (Funneliformis mosseae, Septoglomus viscosum, and Rhizophagus irregularis) were used in combination with three different strains of Pseudomonas sp. (19Fv1t, 5Vm1K and Pf4) to inoculate plantlets of Fragaria × ananassa var. Eliana F1. The effects of the different fungus/bacterium combinations were assessed on plant growth parameters, fruit production and quality, including health-promoting compounds. Inoculated and uninoculated plants were maintained in a greenhouse for 4 months and irrigated with a nutrient solution at two different phosphate levels. The number of flowers and fruits were recorded weekly. At harvest, fresh and dry weights of roots and shoots, mycorrhizal colonization and concentration of leaf photosynthetic pigments were measured in each plant. The following fruit parameters were recorded: pH, titratable acids, concentration of organic acids, soluble sugars, ascorbic acids, and anthocyanidins; volatile and elemental composition were also evaluated. Data were statistically analyzed by ANOVA and PCA/PCA-DA. Mycorrhizal colonization was higher in plants inoculated with R. irregularis, followed by F. mosseae and S. viscosum. In general, AMF mostly affected the parameters associated with the vegetative portion of the plant, while PGPB were especially relevant for fruit yield and quality. The plant physiological status was differentially affected by inoculations, resulting in enhanced root and shoot biomass. Inoculation with Pf4 bacterial strain increased flower and fruit production per plant and malic acid content in fruits, while decreased the pH value, regardless of the used fungus. Inoculations affected fruit nutritional quality, increasing sugar and anthocyanin concentrations, and modulated pH, malic acid, volatile compounds and elements. In the present study, we show for the first time that strawberry fruit concentration of some elements and/or volatiles can be affected by the presence of specific beneficial soil microorganisms. In addition, our results indicated that it is possible to select the best plant-microorganism combination for field applications, and improving fruit production and quality, also in terms of health promoting properties.