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Background: As agriculture has intensified, many once-common wildflowers have declined in arable landscapes, which has wide-spread implications for associated ecosystem services. Incorporation of sustainable practices, for example, growing living mulches (in-field, non-crop plant ground cover, maintained during the target crop growing season), can boost arable biodiversity, but few wildflower species have been utilised in this context. Aims: Our aim was to determine the suitability of arable wildflower species, once considered weeds, for use as living mulches. Methods: We first screened a number of arable wildflower species for germination when growing with a common cereal, barley (Hordeum vulgare). We then grew two (Centaurea cyanus and Scandix pecten-veneris) in pots in a glasshouse with and without barley, and grew barley alone to test the impact of the wildflowers on barley growth and biomass. Results: Neither of the wildflowers significantly negatively impacted barley biomass. Barley initially facilitated germination in S. pecten-veneris, but ultimately suppressed the above-ground biomass of both wildflowers. However, both wildflower species were able to coexist alongside barley. Conclusions: Our experiment provides evidence that wildflowers that were considered weeds in traditional agriculture have the potential to be grown alongside barley and could be incorporated as part of a living mulch.

Tree pathogens are a major threat to forest ecosystems. Conservation management strategies can exploit natural mechanisms of resistance, such as tree genotype and host‐associated microbial communities. However, fungal and bacterial communities are rarely looked at in the same framework, particularly in conjunction with host genotype. Here, we explore these relationships and their influence on ash dieback disease, caused by the pathogen Hymenoscyphus fraxineus, in European common ash trees.\ud \ud We collected leaves from UK ash trees and used microsatellite markers to genotype trees, qPCR to quantify H. fraxineus infection load, and ITS and 16S rRNA amplicon sequencing to identify fungal and bacterial communities, respectively.\ud \ud There was a significant association between H. fraxineus infection intensity and ash leaf fungal and bacterial community composition. Higher infection levels were positively correlated with fungal community alpha diversity, and a number of fungal and bacterial genera were significantly associated with infection presence and intensity. Under higher infection loads, leaf microbial networks were characterised by stronger associations between fewer members than those associated with lower infection levels. Together these results suggest that H. fraxineus disrupts stable endophyte communities after a particular infection threshold is reached, and may enable proliferation of opportunistic microbes. We identified three microbial genera associated with an absence of infection, potentially indicating an antagonistic relationship with H. fraxineus that could be utilised in the development of anti‐pathogen treatments.\ud \ud Host genotype did not directly affect infection, but did significantly affect leaf fungal community composition. Thus, host genotype could have the potential to indirectly affect disease susceptibility through genotype x microbiome interactions, and should be considered when selectively breeding trees.\ud \ud Synthesis. We show the diversity, composition and network structure of ash leaf microbial communities are associated with the severity of infection from ash dieback disease, with evidence of disease‐induced dysbiosis. We also show that host genotype influences leaf fungal community composition, but does not directly influence tree infection. These findings help to elucidate relationships between host genetics, the microbiome, and a tree pathogen, highlighting potential resistance mechanisms and possible co‐infection concerns that could inform ash tree management.

Premise Host-plant genetic variation can shape associated communities of organisms. These community-genetic effects include (1) genetically similar hosts harboring similar associated communities (i.e., the genetic similarity rule) and (2) host-plant heterozygosity increasing associated community diversity. Community-genetic effects are predicted to be less prominent in plant systems with limited genetic variation, such as those at distributional range limits. Yet, empirical evidence from such systems is limited. Methods We sampled a natural population of a mangrove foundation species (Avicennia germinans) at an expanding range limit in Florida, USA. We measured genetic variation within and among 40 host trees with 24 nuclear microsatellite loci and characterized their foliar endophytic fungal communities with internal transcribed spacer (ITS1) gene amplicon sequencing. We evaluated relationships among host-tree genetic variation, host-tree spatial location, and the associated fungal communities. Results Genetic diversity was low across all host trees (mean: 2.6 alleles per locus) and associated fungal communities were relatively homogeneous (five sequence variants represented 78% of all reads). We found (1) genetically similar host trees harbored similar fungal communities, with no detectable effect of interhost geographic distance. (2) Host-tree heterozygosity had no detectable effect, while host-tree absolute spatial location affected community alpha diversity. Conclusions This research supports the genetic similarity rule within a range limit population and helps broaden the current scope of community genetics theory by demonstrating that community-genetic effects can occur even at expanding distributional limits where host-plant genetic variation may be limited. Our findings also provide the first documentation of community-genetic effects in a natural mangrove system.

Diversity among species and genetic diversity within species are both important components of ecological communities that can determine the outcome of species interactions, especially between hosts and parasites. We sought to understand the impact of species diversity on host community resistance to infection by a keystone parasitic plant (Rhinanthus minor L.) and genetic diversity of the parasite on its successful establishment in a grassland community.We used an experimental approach where large pots were planted with mixtures of mesotrophic grassland species at high and low species diversity. The parasitic plant was sown in a proportion of these with high and low genetic diversity treatments. Establishment of the parasite was monitored over 2 years and the pots harvested at the end of each growing season to determine the impact of infection on plant community biomass.We found a strong effect of host plant species diversity on the establishment of the parasitic plant, with successful establishment considerably lower in the high species diversity treatment. Genetic diversity appeared to promote establishment of the parasite in the high species diversity treatment, and also facilitated longer term fitness in the low species diversity treatment. Host community structure was influenced by R. minor, with grass relative biomass decreasing and legume relative biomass increasing when the parasite was present. There was no direct impact of the presence of the parasite on the relative biomass of nonleguminous forbs.Synthesis. Our data demonstrate the importance of host community species diversity in deterring the establishment of a generalist parasite. They also highlight the role of genetic diversity in determining the outcome of host–parasite interactions in multispecies communities. These findings, therefore, have important implications for the establishment and management of species‐rich grasslands and provide insight into the community dynamics of parasitic plants and their hosts.

Wildflower mixes are often planted around field margins to provide forage for pollinators. Although seed for these mixtures is often wild-sourced, for species where agricultural cultivars are available, for example red clover (Trifolium pratense), cultivars can also be included. Previous evidence suggests that plant genetic background can have a strong influence on plant-arthropod interactions and therefore the provenance and genetic background of the plants included in wildflower mixes could impact plant-pollinator interactions. We tested the performance of five individual T. pratense cultivars against two commercially available wild-sourced T. pratense populations in terms of their ability to attract potential pollinator species (focusing on bumblebees) and their floral traits using greenhouse and garden experiments. The main bumblebee observed interacting with T. pratense was Bombus pascuorum and we found no difference in the absolute number of B. pascuorum visiting the cultivars or wild populations. However, we found variation among cultivars and between wild populations in their ability to attract bumblebees, which seems to be related to their relative investment in different floral traits. There was a positive relationship between biomass and number of inflorescences produced by the wild populations of T. pratense, which was not apparent for the cultivars. This suggests that artificial selection on the cultivars has changed the G-matrix of correlated traits. We show that agricultural cultivars of T. pratense can be as effective as wild populations at attracting pollinators such as bumblebees, but that the genetic background of both cultivars and wild populations can have a significant impact on the attractiveness of the plant to pollinators. We also show divergence in the correlated traits of T. pratense cultivars and wild populations that could lead to outbreeding depression if the plants interbreed.

The use of in vitro techniques for conservation has been rising steadily since their inclusion in The Convention on Biological Diversity and The Global Strategy for Plant Conservation. Unfortunately, bryophytes are often overlooked in conservation initiatives, but they are important in a number of large-scale ecosystem processes, i.e. nutrient, water and carbon cycling. There is a long history of the use of tissue culture in cultivating bryophytes, and many species respond well to in vitro techniques. For 6 yr (2000–2006), The Royal Botanic Gardens, Kew and the UK statutory conservation agencies supported a project for the ex situ conservation of bryophytes. Living and cryopreserved collections of UK threatened species were successfully established and the cryopreserved collection continues to be maintained. Other in vitro conservation collections are maintained over Europe, at botanic gardens, museums and by individual university researchers, but there is no coherent European collection of bryophytes for conservation, or standardisation of techniques. A major issue for many in vitro collections is the maintenance of within species genetic diversity. Such diversity is considered to be important, as it is the basis by which populations of species can adapt to new conditions and evolve. We are proposing to establish a European network for in vitro conservation of bryophytes. We envisage that this will include living collections, cryopreserved collections and spore collections. Conservation of genetic diversity would be a priority and the collections would provide a valuable resource for conservation initiatives and support research into rare and threatened species.

Background and Aims Successful cryopreservation of bryophytes is linked to intrinsic desiccation tolerance and survival can be enhanced by pre-treatment with abscisic acid (ABA) and sucrose. The pioneer moss Ditrichum plumbicola is naturally subjected to desiccation in the field but showed unexpectedly low survival of cryopreservation, as well as a poor response to pre-treatment. The effects of the cryopreservation protocol on protonemata of D. plumbicola were investigated in order to explore possible relationships between the production in vitro of cryopreservation-tolerant asexual propagules and the reproductive biology of D. plumbicola in nature. Methods Protonemata were prepared for cryopreservation using a four-step protocol involving encapsulation in sodium alginate, pre-treatment for 2 weeks with ABA and sucrose, desiccation for 6 h and rapid freezing in liquid nitrogen. After each stage, protonemata were prepared for light and electron microscopy and growth on standard medium was monitored. Further samples were prepared for light and electron microscopy at intervals over a 24-h period following removal from liquid nitrogen and re-hydration. Key Results Pre-treatment with ABA and sucrose caused dramatic changes to the protonemata. Growth was arrested and propagules induced with pronounced morphological and cytological changes. Most cells died, but those that survived were characterized by thick, deeply pigmented walls, numerous small vacuoles and lipid droplets in their cytoplasm. Desiccation and cryopreservation elicited no dramatic cytological changes. Cells returned to their pre-dehydration and cryopreservation state within 2 h of re-hydration and/or removal from liquid nitrogen. Regeneration was normal once the ABA/sucrose stimulus was removed. Conclusions The ABA/sucrose pre-treatment induced the formation of highly desiccation- and cryopreservation-tolerant propagules from the protonemata of D. plumbicola. This parallels behaviour in the wild, where highly desiccation-tolerant rhizoids function as perennating organs allowing the moss to endure extreme environmental conditions. An involvement of endogenous ABA in the desiccation tolerance of D. plumbicola is suggested.

In vitro techniques have found increasing use in the conservation of threatened plants in recent years and this trend is likely to continue as more species face risk of extinction. The Micropropagation Unit at Royal Botanic Gardens, Kew, UK (RBG Kew) has an extensive collection of in vitro plants including many threatened species from throughout the world. The long history of the unit and the range of plants cultured have enabled considerable expertise to be amassed in identifying the problems and developing experimental strategies for propagation and conservation of threatened plants. While a large body of knowledge is available on the in vitro culture of plants, there are limited publications relating to threatened plant conservation. This review highlights the progress in in vitro culture and conservation of threatened plants in the past decade (1995–2005) and suggests future research directions. Works on non-threatened plants are also included wherever methods have applications in rare plant conservation. Recalcitrant plant materials collected from the wild or ex situ collections are difficult to grow in culture. Different methods of sterilization and other treatments to establish clean material for culture initiation are reviewed. Application of different culture methods for multiplication, and use of unconventional materials for rooting and transplantation are reviewed. As the available plant material for culture initiation is scarce and in many cases associated with inherent problems such as low viability and endogenous contamination, reliable protocols on multiplication, rooting, and storage methods are very important. In this context, photoautotrophic micropropagation has the potential for development as a routine method for the in vitro conservation of endangered plants. Long-term storage of material in culture is challenging and the potential applications of cryopreservation are significant in this area. Future conservation biotechnology research and its applications must be aimed at conserving highly threatened, mainly endemic, plants from conservation hotspots.

The systemic herbicide asulam is used extensively to control the weedy fern bracken ( Pteridium aquilinum (L.) Kuhn). Other ferns were thought to be highly sensitive to asulam exposure, but there has been a dearth of experimental evidence. Eight fern species were exposed to asulam spray at three different application rates or a control of water. Asulam was applied at the recommended field application rate for bracken clearance, and at two further rates corresponding to 10 and 50 m downwind of an aerial spray event. Damage was assessed over two seasons. All ferns tested were severely damaged by exposure to the highest application rate, but sensitivity varied between species. Maximum damage occurred 1 year after spraying, and limited signs of recovery could be seen by the second season. The effects of adding the adjuvant Agral® to applications of asulam were tested on the threatened pteridophyte Pilularia globulifera L. No damage additional to that caused by exposure to asulam was observed. This work supports the view that 50 m buffer zones are sufficient to protect sensitive ferns from the effects of aerial spraying with asulam, provided that drift-reducing nozzles are used and the manufacturer’s application guidelines are observed.

Protonemata of three mosses (Bryum rubens Mitt., Campylopus introflexus (Hedw.) Brid,. and Polytrichum formosum Hedw.) were exposed in sterile cultures to low concentrations of the bracken herbicide asulam, added to the solidified growth medium. Protonemata were either exposed for 24 hours and then transferred onto media without asulam, or exposed constantly to the asulam media. Growth was measured over a three-week period as the mean of two plug diameters, and development of leafy gametophores was noted. A 24-hour exposure period to asulam had no effect on the growth or development of the mosses at concentrations of 0.001–1 g a.i. (active ingredient) l−1. The growth and development of all three species was significantly affected by continuous exposure to asulam at concentrations of 0.01 g a.i. l−1 and above. Dose-response curves were fitted to the data and EC50 values calculated. Campylopus introflexus was the least sensitive species tested and P. formosum the most sensitive, with a 10-fold diff...

Asulox is a herbicide used to control bracken. Its effects on mosses were investigated to ascertain whether exposure proved as detrimental as found in parallel studies on pteridophytes. Mature gametophytes of 18 mosses were exposed to a range of concentrations of Asulox under standard conditions and the effects on growth monitored. Plants were cut to a standard length, exposed to Asulox solution for 24 h, grown for 3 weeks and total elongation (main stem and branches) measured. EC50 values were calculated and species ranked according to sensitivity. The effects of exposure on total elongation were compared with those on main stem elongation alone. Under the conditions tested, the total elongation of all species was inhibited after exposure to Asulox. The amount of elongation observed after exposure was different for different species and inhibition of elongation occurred at different exposure concentrations. A single regression equation was not adequate to describe the dose response curves of all species tested. An ability to produce secondary branches may confer increased tolerance to Asulox exposure. It is concluded that mosses suffer detrimental effects after exposure to Asulox at concentrations similar to those that affect fern gametophytes such as bracken.

The effects of genetic variation in species can have large impacts on direct and indirect species interactions, associated biodiversity and ecosystem function. Biodiversity and ecosystem function can change as a consequence of evolutionary dynamics (Barbour et al., 2009), thus, linking evolution strongly with community and ecosystem ecology. At the 2011 International Botanical Congress in Melbourne, Australia, a symposium entitled, ‘Community and ecosystem genetics: the extended genetic effects of plant species’, examined new research in the field of community and ecosystem genetics. Talks focused on: links between contemporary ecological interactions and historic evolutionary dynamics; the role of feedbacks as mechanisms in driving patterns of biodiversity and ecosystem function; and application of these approaches to management and conservation issues as they relate to global change. The symposium concluded that an understanding of evolutionary divergence and adaptation, and the role of ecological feedbacks in natural systems, will be fundamental to successful outcomes in future conservation, restoration and management decisions.

Local adaptation may be important for the preservation of genetic diversity and the promotion of speciation. However, local adaptation may also constrain establishment in different environments. The consequences of local adaptation depend strongly on the pleiotropic effects of the genes involved in adaptation. Here, we investigated the pleiotropic effects of the genetic response to selection in outbred lines of Arabidopsis artificially selected to flower earlier under both winter- and spring-annual simulated conditions. The consequences of adaptation were evaluated by reciprocally transplanting selected and control lines between the two conditions. Selected lines always flower earlier than their controls, independent of growing conditions. However, selected lines, growing in the same condition in which they were selected, flower earlier than plants selected in the alternative environment. Plants selected to flower earlier in spring produce more fruits than controls when growing in the spring, and less fruits when growing in the winter; indicating that local adaptation has negative pleiotropic effects in another environment. Our results indicate that local adaptation can arise even when selection targets the same trait in the same direction. Furthermore, it suggests that adaptation under the two different environments can generate fitness trade-offs that can maintain genetic variation for flowering time.

Physcomitrella patens – the so-called Arabidopsis of the moss world or ‘green yeast’ – is the first non-vascular plant to have its genome sequenced. This book is a review of previous and current research on this model moss and an invitation for others to consider using P. patens for their work. This is a beautifully produced, well edited and generally easy-to-read volume for plant scientists. Bryological terms are well explained and there is a useful glossary for those unfamiliar with some common bryological terms and concepts. More knowledge is assumed with regard to molecular techniques, and an expanded glossary for those perhaps more familiar with the bryology but less so with the experimental biology would have been useful. Such an addition might also widen the target audience somewhat from the specialist plant scientist to the interested biologist. The editors state in the preface that the book covers a broad range of topics including evolutionary and ecological studies using P. patens, its unique features and particular value in a variety of molecular work, as well as the use of P. patens to investigate standard biological processes. They have, on the whole, produced such a book and should be congratulated for this achievement. There is a focus on molecular work, which reflects the bulk of research to date on P. patens, but serious attempts are made to widen the scope and address some of the scientific gaps in recent studies. The opening chapter is an up-to-date and easy-to-understand introduction to the current state of knowledge of the evolutionary history of land plants, and the positioning of bryophytes, especially mosses, on the tree of life. Despite promises in the chapter title, ecology is scarcely covered, which highlights the main omission in this volume and also previous research. Chapter 2 gives an excellent overview of the limited amount of experimental evolutionary studies on mosses in general, suggesting that ‘classical genetic analysis of natural variation has been under utilised in the moss research community of late’. How true this is! This chapter pertinently illuminates the vast and exciting possibilities for future research in this area. Of particular interest is the recent development of P. patens mapping lines by the author. Further chapters cover a vast range of research areas, some better established than others. Topics include: genomics, gene targeting and small RNAs, development, maintenance and the stress responses of P. patens. The exploration of gametangial development is accompanied by some clear figures that nicely illustrate the different growth stages, while the explanation of gene trapping techniques to identify novel genes important in development brings this section up to date. The chapter on the role of abscissic acid in stress (particularly dehydration and desiccation) is clear and succinct, providing a good overview of the current state of knowledge. The final chapter on pathogenesis in mosses is a comprehensive view of the great potential for using P. patens in molecular plant pathology studies. Interestingly, P. patens appears to be susceptible to numerous infections in the lab, yet is much less susceptible to disease in nature – although as the authors point out, this is likely due to limited sampling in the field. The section of colour prints in the middle of the book is formed from a composite of figures from the different chapters. This was initially confusing, but the beautiful colour prints are a wonderful addition and serve to highlight the difference in detail that can be observed from the black and white photographs. This is an excellent book on P. patens and will hopefully encourage its further use by molecular plant scientists. However, the scope of this book is broader and it should also be of interest to evolutionary biologists and ecologists. Just as the value of Arabidopsis in such studies is increasing, I hope that this book is the spark that ignites greater amounts of research on the evolution and ecology of mosses.

Our last review, of the first edition, was broadly favourable, but made several suggestions that have not been taken up. Doubtless the editors had many conflicts to resolve, but while this compilation may prove enormously frustrating for the non-expert, it certainly does fit the back cover description‘..an authoritative treatment of bryophyte biology, with rich citation of the current literature, suitable for advanced students and researchers’. There remain no references to being ‘accessible and well illustrated’ (in the first edition), so the editors have obviously decided to pitch to the cognoscenti. The book achieves its aims – providing the reader has an understanding of the meaning of terms such as ‘prosenchymatous’, ‘anacrogynous’, ‘Bauplan’, ‘superincumbent’ and ‘nematodontous’ or access to a good bryological dictionary, there is a huge amount of useful information to be had. Illustrations are sparse and exclusively black and white, but typographical errors are very few (e.g. achegoniate) and mismatch of message the same (please let's agree on substrate/substratum!), so the reader is faced with an exceptionally rich and well-edited resource. The editors have collected many of the major bryological players and generated a tome of enormous merit. We take exception to the concept of the bryophyte life cycle being ‘peculiar’ (p. 394) as we are comfortable that it is the master plan, with all subsequent life cycles being mere derivatives, but have few other constitutional disagreements. Once again, the book starts with morphology and classification – not for the faint hearted, and laden with jargon, but bang up to date and richly referenced. We especially liked the idea of ‘papillae as snorkels emerging from the water surface’ and were intrigued to learn that leafy shoots remain viable after passage through bats. The going gets easier with the chapter on ‘mosses as model organisms … ’ by Andrew Cuming, a refreshing non-‘Arabidocentric’ view of the plant kingdom that makes recent research extremely accessible to the non-expert. Michael Proctor continues the tone – we especially liked the explanation of desiccation tolerance as the reversible biological equivalent of good electron microscopy fixation! Jeff Bates shows a particularly keen awareness of recent developments in his account of mineral nutrition and substratum ecology, and his section on internal recycling is an incredibly useful compilation. Alain Vanderpoorten and Tomas Hallingback's chapter on conservation is as information-dense as the rest of the book. All of the chapters require a careful read, and re-read with a dictionary at hand, but the attention is richly repaid. To anyone embarking on conservation projects involving bryophytes – read this chapter first! This is a comprehensive review of why bryophytes need conserving – but serves to highlight how little we actually know. Places of conservation interest for bryophytes only partially overlap areas of interest for angiosperms and animals. This suggests that bryophytes are not good indicators of overall diversity but follow different rules. It is a pity that the authors have missed recent papers showing that desiccation-intolerant species can be cryopreserved, but this is a minor complaint. We end with an unapologetic self-plagiarized quote from the review of the first edition – this ‘should be an essential purchase for budding bryologists with plenty of background literature to hand, to all established bryological researchers [we defy you not to learn something new!] and to all libraries’.