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Despite the importance of secondary dormancy for plant life cycle timing and survival, there is insufficient knowledge about the (epigenetic) regulation of this trait at the molecular level. Our aim was to determine the role of (epi)genetic processes in the regulation of secondary seed dormancy using natural genotypes of the widely distributedCapsella bursa-pastoris. Seeds of nine ecotypes were exposed to control conditions or histone deacetylase inhibitors [trichostatin A (TSA), valproic acid] during imbibition to study the effects of hyper-acetylation on secondary seed dormancy induction and germination. Valproic acid increased secondary dormancy and both compounds caused a delay of t50 for germination (radicle emergence) but not of t50 for testa rupture, demonstrating that they reduced speed of germination. Transcriptome analysis of one accession exposed to valproic acidversuswater showed mixed regulation of ABA, negative regulation of GAs, BRs and auxins, as well as up-regulation ofSNLgenes, which might explain the observed delay in germination and increase in secondary dormancy. In addition, two accessions differing in secondary dormancy depth (deepvsnon-deep) were studied using RNA-seq to reveal the potential regulatory processes underlying this trait. Phytohormone synthesis or signalling was generally up-regulated for ABA (e.g.NCED6,NCED2,ABCG40,ABI3) and down-regulated for GAs (GA20ox1,GA20ox2,bHLH93), ethylene (ACO1,ERF4-LIKE, ERF105,ERF109-LIKE), BRs (BIA1,CYP708A2-LIKE, probableWRKY46,BAK1,BEN1,BES1,BRI1) and auxin (GH3.3,GH3.6,ABCB19,TGG4,AUX1,PIN6,WAT1). Epigenetic candidates for variation in secondary dormancy depth includeSNLgenes, histone deacetylases and associated genes (HDA14,HDA6-LIKE,HDA-LIKE,ING2,JMJ30), as well as sequences linked to histone acetyltransferases (bZIP11,ARID1A-LIKE), or to gene silencing through histone methylation (SUVH7,SUVH9,CLF). Together, these results show that phytohormones and epigenetic regulation play an important role in controlling differences in secondary dormancy depth between accessions.

Ecological Intensification (EI) is the enhancement of ecosystem services to complement or substitute for the role of anthropogenic inputs in maintaining or increasing yields. EI has potential to increase farming’s environmental sustainability, for example reducing environmentally harmful management activities while sustaining yields. EI is based upon ecological processes which in turn are influenced by biodiversity. We review how biodiversity — particularly vascular plant diversity — can regulate ecosystem processes relevant to EI at multiple spatial scales. At an individual plant genotype level, complementarity in functional traits has a direct impact on productivity. At in-field, population level, mixtures of crop types confer resilience to minimise the risk of pest and disease incidence and spread. Scaling up to the field level, a diversity of non-crop plants (i.e. weeds) provides resources necessary for in-field functional processes, both below ground (carbon inputs, decomposition) and above ground (resource continuity for pollinators and natural enemies). At the landscape scale, mosaics of semi-natural and managed vegetation provide buffers against extreme events through flood and drought risk mitigation, climate amelioration and pest population regulation. Overall this emphasises the importance of heterogeneity across scales in maintaining ecosystem functions in farmland. Major research challenges highlighted by our review include the need: to better integrate plant functional diversity (from traits to habitat scales) into cropping system design; to quantify the (likely interactive) contribution of plant diversity for effective EI relative to other management options; and to optimise through targeted management the system function benefits of biodiversity for resilient, efficient and productive agroecosystems.

This study aims to explore the possibility of a reduced application of inorganic nitrogen (N) fertiliser on the yield, yield qualities, and biological nitrogen fixation (BNF) of the hydroponic common bean (Phaseolus vulgaris L.), without compromising plant performance, by utilizing the inherent ability of this plant to symbiotically fix N2. Until the flowering stage, plants were supplied with a nutrient solution containing N-concentrations of either a, 100%, conventional standard-practice, 13.8 mM; b, 75% of the standard, 10.35 mM; or c, 50% of the standard, 6.9 mM. During the subsequent reproductive stage, inorganic-N treatments b and c were decreased to 25% of the standard, and the standard (100% level) N-application was not altered. The three different inorganic-N supply treatments were combined with two different rhizobia strains, and a control (no-inoculation) treatment, in a two-factorial experiment. The rhizobia strains applied were either the indigenous strain Rhizobium sophoriradicis PVTN21 or the commercially supplied Rhizobium tropici CIAT 899. Results showed that the 50–25% mineral-N application regime led to significant increases in nodulation, BNF, and fresh-pod yield, compared to the other treatment, with a reduced inorganic-N supply. On the other hand, the 75–25% mineral-N regime applied during the vegetative stage restricted nodulation and BNF, thus incurring significant yield losses. Both rhizobia strains stimulated nodulation and BNF. However, the BNF capacity they facilitated was suppressed as the inorganic-N input increased. In addition, strain PVTN21 was superior to CIAT 899—as 50–25% N-treated plants inoculated with the former showed a yield loss of 11%, compared to the 100%-N-treated plants. In conclusion, N-use efficiency optimises BNF, reduces mineral-N-input dependency, and therefore may reduce any consequential negative environmental consequences of mineral-N over-application.

The aim of the current study wat to comparatively assess the impact of different nitrogen (N) fertilization schemes on fresh pod yield and yield quality in either organically or conventionally grown common beans (Phaseolus vulgaris L.). Prior to common bean crop establishment, the experimental field site was cultivated following either organic (a) or conventional (b) farming practices with a winter non-legume crop (Brassica oleracea var. italica) (BR), or (c) with field bean (Vicia faba sp.) destined to serve as a green manure (GM) crop. At the end of the winter cultivation period the broccoli crop residues (BR) and green manure biomass (GM) were incorporated into the soil and the plots that accommodated the treatments (a) and (c) were followed by an organically cultivated common bean crop, while the conventional broccoli crop was followed by a conventionally cropped common bean crop. Additional to the plant residues (BR), sheep manure (SM) at a rate of 40 kg N ha−1 was also applied to the organically treated common beans, while the plots with a conventionally cropped common bean received 75 kg N ha−1. Organic common bean treated with SM + BR produced smaller pods of higher dry matter and bioactive compound content, responses that are correlated with limited soil N availability. No significant variations were observed on yield components and N levels of pods cultivated under organic (SM + GM) and conventional cropping systems. Pod sugar and starch content was not influenced by the different fertilization practices. In conclusion, we have demonstrated that the combined application of SM + GM can be considered as an efficient N-fertilisation strategy for organic crops of common bean, benefiting their nutritional value without compromising yield.

Well-managed legume-based food systems are uniquely positioned to curtail theexistential challenge posed by climatechangethrough the significant contributionthat legumes can make toward limiting Green House Gas (GHG) emissions. Thispotential is enabled by the specific functional attributes offered only by legumes,which deliver multiple co-benefits through improved ecosystem functions, includingreduced farmland biodiversity loss, and better human-health and -nutrition provisioning.These three critical societal challenges are referred to collectively here as the“climate-biodiversity-nutrition nexus.” Despite the unparalleled potential of the provisionsoffered by legumes, this diverse crop group remains characterized as underutilizedthroughout Europe, and in many regions world-wide. This commentary highlightsthat integrated, diverse, legume-based, regenerative agricultural practices shouldbe allied with more-concerted action on ex-farm gate factors at appropriatebioregional scales.Also,thatthiscanbeachievedwhilstoptimizing production, safeguarding food-security, and minimizing additional land-use requirements. To helpavoid forfeiting the benefits of legume cultivation for system function, a specificand practical methodological and decision-aid framework is offered. This is basedupon the identification and management of sustainable-development indicators forlegume-based value chains, to help manage the key facilitative capacities anddependencies. Solving the wicked problems of the climate-biodiversity-nutrition nexus demands complex solutions and multiple benefits and this legume-focus must beallied with more-concerted policy action, including improved facilitation of the catalyticprovisions provided by collaborative capacity builders—to ensure that the knowledgenetworks are established, that there is unhindered information flow, and that newtransformative value-chain capacities and business models are established.

Aims Myxospermous seed mucilage is multifunctional and is often found in seeds (or achenes) of species occupying arid environments where the trait may influence seed-dispersal and -germination of seeds. The seed mucilage may also enhance soil-water retention, −hydraulic conductivity and -stability. However, the relationship between seed mucilage quantity, seed germination and seedling traits across environmental gradients which determine water-deficit stress has not yet been ascertained. Methods Therefore, we characterised and tested the relationship between seed mucilage quantity, water-deficit stress responses of seeds and seedlings of 36 accessions of four different Plantago species (P. albicans L., P. coronopus L., P. lagopus L. and P. anceolata L.). These were gathered from six regions across Europe, which presented environmental gradients (of rainfall and temperature), and varying soil qualities. Results Seed mucilage was significantly greater in seeds of accessions experiencing: highest summer temperatures; lowest summer precipitation; soils of the same warm dry regions which had greater capacity to retain water within narrow pore spaces. Under water-deficit stress, seeds with most mucilage exhibited a lower base water potential for germination, suffered least seedling mortality and exhibited the most successful seedling development. Conclusions The findings indicate that seed mucilage quantity appeared as an ‘adaptive’ trait and there is a relationship between seed-mucilage quantity, seed germination plus seedling survival and development under environmental conditions of highest water-deficit stress.

The Biospeckle Laser (BSL) induced phenomenon is recorded as light scattered from the surface of illuminated test material, and the methodology is established as a tool for the non-destructive assessment of biological tissues. The output of BSL-based recording is normally numeric data that are processed to generate graphical and visual information. However, BSL outputs could presented in a qualitative audible format as a rapid means by which a test-tissues physiological states may be classified. Here we report a new BSL-data processing methodology that was able to discriminate viable and dead beans (seeds) of coffee (Coffea arabica L.) using single- and multi-frequency wavelength models. BSL-data was rapidly converted from the traditional numeric (graphical) output into forms (‘biospeckle index’) audible to the human ear. The utility and significance of this novel BSL-audio approach is discussed.

Despite the importance of dormancy and dormancy cycling for plants’ fitness and life cycle phenology, a comprehensive characterization of the global and cellular epigenetic patterns across space and time in different seed dormancy states is lacking. Using Capsella bursa-pastoris (L.) Medik. (shepherd’s purse) seeds with primary and secondary dormancy, we investigated the dynamics of global genomic DNA methylation and explored the spatio-temporal distribution of 5-methylcytosine (5-mC) and histone H4 acetylated (H4Ac) epigenetic marks. Seeds were imbibed at 30 °C in a light regime to maintain primary dormancy, or in darkness to induce secondary dormancy. An ELISA-based method was used to quantify DNA methylation, in relation to total genomic cytosines. Immunolocalization of 5-mC and H4Ac within whole seeds (i.e., including testa) was assessed with reference to embryo anatomy. Global DNA methylation levels were highest in prolonged (14 days) imbibed primary dormant seeds, with more 5-mC marked nuclei present only in specific parts of the seed (e.g., SAM and cotyledons). In secondary dormant seeds, global methylation levels and 5-mC signal where higher at 3 and 7 days than 1 or 14 days. With respect to acetylation, seeds had fewer H4Ac marked nuclei (e.g., SAM) in deeper dormant states, for both types of dormancy. However, the RAM still showed signal after 14 days of imbibition under dormancy-inducing conditions, suggesting a central role for the radicle/RAM in the response to perceived ambient changes and the adjustment of the seed dormancy state. Thus, we show that seed dormancy involves extensive cellular remodeling of DNA methylation and H4 acetylation.

The success of seed-based conservation and restoration efforts using native plant species is largely determined by ensuring two key life history transitions are accommodated. These are from “seed to germinated seed” and “germinated seed to established seedling.” In turn, optimization of these life history transitions is determined by a “genetic × environmental” interaction and later largely characterized by localized climatic (abiotic) conditions. It is these environmental stress factors that can act as natural selection agents for specific plant–trait combinations, or phenotypes. In turn, such adaptation may also limit a species range. To test the relationship between these two early plant life history stage transitions, “seed to germinated seed” and “germinated seed to established seedling,” the attributes were characterized for two species of Plantago that occupy contrasting environments and since these species have potential for native seed-based habit restoration and conservation. The species were Plantago coronopus (L.), localized at lower and drier altitudes, and Plantago lanceolata (L.), characterized as occupying higher and wetter altitudinal clines. Seeds were collected from 20 accessions of six natural populations spanning four European countries for both P. lanceolata and P. coronopus. Seed germination (G) and seedling establishment (S) data were determined at six temperatures (T) and six water potentials (Ψ), and the data obtained were analyzed using a generalized linear model (GLM). The results indicate that P. coronopus has adapted physiologically to its high-altitude conditions such that seed germination and seedling establishment may be more readily achieved in this cooler environment where water is less limiting. In contrast, the lower θT of P. lanceolata better facilitates more efficient seed germination and seedling establishment in drier and warmer clines of lower altitude. In addition to establishing a genotypic (species) underpin for seed and seedling trait differences observed, the insights gained may also be exploited to best deploy each species in situ for seed-based conservation and restoration efforts.

Legume grains are traditional crops that have been modernized as processed foods and animal protein alternatives in recent years. This modernization has largely been fueled by new technological developments driven by increased consumer demands for plant protein and gluten-free options. However, consumers must be mindful that legumes have other nutritional attributes besides protein that help achieve healthier diets, and recent evidence suggests that consuming 100 g of legume grains per day would promote nutrient-dense diets and could be a target level to harmonize international strategies for recommended daily allowances. The nutritional richness of legumes has been associated with a decrease in numerous disease risk factors and, given their long shelf life, legumes are excellent choices to combat food waste and may have a role to play in countries where cold storage is often a limitation in food preservation. Besides their inclusion in global diets, legumes should be included in sustainable cropping systems. The high number of edible species and cultivars available render them excellent contributors to biodiverse food and feed systems. Legume cultivation allows reducing environmental impacts by means of the ability of legumes to fix atmospheric nitrogen via a symbiosis with nitrogen-fixing bacteria, making them natural fertilizers. Still, despite the well-known health, nutritional, and environmental benefits, legumes are underrepresented in global agri-food systems. Efforts must be made to make legumes more attractive to the farmer, the industry, and ultimately the consumer, and for this proper local, regional, national, and global policy frameworks must be in place. Here, the local scenario of legumes is showcased, and the most relevant push, pull, and enabling capacities required to achieve sustainable diversified agri-food systems with legumes are discussed.

The potential to utilize low nitrogen barley for production of distilling quality malt was studied.This presents an opportunity to reduce the environmental impact of nitrogen fertilizer applications.Malting barley (cv. Octavia) was grown without the application of inorganic nitrogen fertilizer,to produce grain with a relatively low nitrogen concentration (1.16%, dry weight basis).Following micro-malting trials, dextrinizing units (58 DU) obtained from low nitrogen malt weremuch higher than a typical specification of 45 DU for malt with a conventional nitrogen concentration(

Common bean (Phaseolus vulgaris L.) is the most important legume for human consumption worldwide and an important source of vegetable protein, minerals, antioxidants, and bioactive compounds. The N2-fixation capacity of this crop reduces its demand for synthetic N fertilizer application to increase yield and quality. Fertilization, yield, and quality of common bean may be optimised by several other agronomic practices such as irrigation, rhizobia application, sowing density, etc. Taking this into consideration, a systematic review integrated with a bibliometric analysis of several agronomic practices that increase common bean yield and quality was conducted, based on the literature published during 1971–2021. A total of 250 publications were found dealing with breeding (n = 61), sowing density and season (n = 14), irrigation (n = 36), fertilization (n = 27), intercropping (n = 12), soilless culture (n = 5), tillage (n = 7), rhizobia application (n = 36), biostimulant/biofertilizer application (n = 21), disease management (n = 15), pest management (n = 2) and weed management (n = 14). The leading research production sites were Asia and South America, whereas from the Australian continent, only four papers were identified as relevant. The keyword co-occurrence network analyses revealed that the main topics addressed in relation to common bean yield in the scientific literature related to that of “pod”, “grain”, “growth”, “cultivar” and “genotype”, followed by “soil”, “nitrogen”, “inoculation”, “rhizobia”, “environment”, and “irrigation”. Limited international collaboration among scientists was found, and most reported research was from Brazil. Moreover, there is a complete lack in interdisciplinary interactions. Breeding for increased yield and selection of genotypes adapted to semi-arid environmental conditions combined with the suitable sowing densities are important agronomic practices affecting productivity of common bean. Application of fertilizers and irrigation practices adjusted to the needs of the plants according to the developmental stage and selection of the appropriate tillage system are also of high importance to increase common bean yield and yield qualities. Reducing N-fertilization via improved N-fixation through rhizobia inoculation and/or biostimulants application appeared as a main consideration to optimise crop performance and sustainable management of this crop. Disease and weed management practices appear neglected areas of research attention, including integrated pest management.

Testing rhizobial inoculation of common bean (Phaseolus vulgaris L.) in hydroponics enables accurate quantification of biological N2 fixation (BNF) and provides information about the potential of reducing inorganic N fertilizer use. In view of this background, common bean grown on pumice was inoculated with Rhizobium tropici CIAT899 (Rt) and supplied with either full-N (total nitrogen 11.2 mmol L-1 ), 1/3 of full-N or N-free nutrient solution (NS). BNF was quantified at the early pod-filling stage using the 15 N natural abundance method.; Results: Full-N supply to Rt-inoculated plants resulted in markedly smaller nodules than less- or zero-N supply, and no BNF. Rt inoculation of full-N-treated plants did not increase biomass and pod yield compared with non-inoculation. Restriction (1/3 of full-N) or omission of inorganic N resulted in successful nodulation and BNF (54.3 and 49.2 kg N ha-1 , corresponding to 58 and 100% of total plant N content respectively) but suppressed dry shoot biomass from 191.7 (full-N, +Rt) to 107.4 and 43.2 g per plant respectively. Nutrient cation uptake was reduced when inorganic N supply was less or omitted.; Conclusion: Rt inoculation of hydroponic bean provides no advantage when full-N NS is supplied, while 1/3 of full-N or N-free NS suppresses plant biomass and yield, partly because the restricted NO3- supply impairs cation uptake. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.

Legume grains are traditional crops that have been modernized as processed foods and animal protein alternatives in recent years. This modernization has largely been fueled by new technological developments driven by increased consumer demands for plant protein and gluten-free options. However, consumers must be mindful that legumes have other nutritional attributes besides protein that help achieve healthier diets, and recent evidence suggests that consuming 100 g of legume grains per day would promote nutrient-dense diets and could be a target level to harmonize international strategies for recommended daily allowances. The nutritional richness of legumes has been associated with a decrease in numerous disease risk factors and, given their long shelf life, legumes are excellent choices to combat food waste and may have a role to play in countries where cold storage is often a limitation in food preservation. Besides their inclusion in global diets, legumes should be included in sustainable cropping systems. The high number of edible species and cultivars available render them excellent contributors to biodiverse food and feed systems. Legume cultivation allows reducing environmental impacts by means of the ability of legumes to fix atmospheric nitrogen via a symbiosis with nitrogen-fixing bacteria, making them natural fertilizers. Still, despite the well-known health, nutritional, and environmental benefits, legumes are underrepresented in global agri-food systems. Efforts must be made to make legumes more attractive to the farmer, the industry, and ultimately the consumer, and for this proper local, regional, national, and global policy frameworks must be in place. Here, the local scenario of legumes is showcased, and the most relevant push, pull, and enabling capacities required to achieve sustainable diversified agri-food systems with legumes are discussed.

Background There is an urgent need to ensure that food production is maintained in response to either a reduction in use or lack of availability of natural resources. To this end, several strategies have been investigated to determine which agronomic approaches may improve crop yields under conditions of reduced water and/or nutrients provision, with special attention upon nitrogen (N) and phosphorus (P). New technologies and practices have been developed for key commercial crops, such as tomatoes. However, few of these are widely adopted in the field and evidence of their value in this production setting is limited. Methods This protocol sets out a systematic map methodology that aims to provide a coherent synthesis of the available evidence among the literature on the techniques and management approaches that may ensure the productivity of field-grown tomatoes under conditions of water-, N- and/or P-deficits, either as single or combined stresses. To conduct the literature search, a search strategy was produced to define the scope of the systematic map and to allow reproducibility of the approach. A list of published and unpublished sources of literature were selected and a preliminary trial identified best-fit-for-purpose search-terms and -strings. A literature screening process was set with consistency checks amongst reviewers at the title, abstract and full text screening stages. A series of eligibility criteria were defined to ensure objectivity and consistency in the selection of studies that are best suited to address the research question of the systematic map. In addition, a coding strategy was designed to set the means for meta-data extraction out from the literature for review. A drafted structured questionnaire will serve as the base for collating the meta-data to produce a database where variables will be queried for the evidence synthesis. This work is expected to inform stakeholders, researchers and policy makers regarding the extent and nature of the existing evidence base, and so serve as a basis by-which specific approaches may be highlighted as potential focal-areas in future.

Industrialised agriculture is heavily reliant upon synthetic nitrogen fertilisers and imported protein feeds, posing environmental and food security challenges. Increasing the cultivation of leguminous crops that biologically fix nitrogen and provide high protein feed and food could help to address these challenges. We report on the innovative use of an important leguminous crop, pea (Pisum sativum L.), as a source of starch for alcohol (gin) production, yielding protein-rich animal feed as a co-product. We undertook life cycle assessment (LCA) to compare the environmental footprint of 1 L of packaged gin produced from either 1.43 kg of wheat grain or 2.42 kg of peas via fermentation and distillation into neutral spirit. Allocated environmental footprints for pea-gin were smaller than for wheat-gin across 12 of 14 environmental impact categories considered. Global warming, resource depletion, human toxicity, acidification and terrestrial eutrophication footprints were, respectively, 12%, 15%, 15%, 48% and 68% smaller, but direct land occupation was 112% greater, for pea-gin versus wheat-gin. Expansion of LCA boundaries indicated that co-products arising from the production of 1 L of wheat- or pea-gin could substitute up to 0.33 or 0.66 kg soybean animal feed, respectively, mitigating considerable greenhouse gas emissions associated with land clearing, cultivation, processing and transport of such feed. For pea-gin, this mitigation effect exceeds emissions from gin production and packaging, so that each L of bottled pea gin avoids 2.2 kg CO2 eq. There is great potential to scale the use of legume starches in production of alcoholic beverages and biofuels, reducing dependence on Latin American soybean associated with deforestation and offering considerable global mitigation potential in terms of climate change and nutrient leakage — estimated at circa 439 Tg CO2 eq. and 8.45 Tg N eq. annually. Keywords: Pea, Legumes, Life cycle assessment, LCA, Animal feed, DDGS, Distillation, Ethanol

Production of animal-based protein is a significant global source of greenhouse gases, a major driver of agricultural land use and a source of nutrient loss to the environment. In this study, we provide a new assessment of the current sources of proteins in the human diet and analyze the options for increasing the use of plant-based sources, taking the protein quality, as indicated by the amino acid composition, into account. The results demonstrate the importance of sustainable global supply of lysine, one of the amino acids essential for human nutrition. It is demonstrated here that the current production of plant-based lysine that can be considered as replacement of lysine obtained from animal protein largely comes from soybean originating from a small number of countries. There are limited large-scale options to broaden the supply of plant-based lysine, namely increase of soya production outside its current main production areas, increase of production of legumes other than soya or other lysine-rich crops, obtaining plantbased lysine from sources not currently used for human consumption, or manufacturing lysine from non-standard plant-based sources (e.g., through fermentation from sugar). All of these options would require major changes in the structure of global agricultural production and associated agri-food systems and would especially have consequences on agricultural land use.

The long-term sustainability of crop production depends on the complex network of interactions and trade-offs between biotic, abiotic and economic components of agroecosystems. An integrated arable management system was designed to maintain yields, whilst enhancing biodiversity and minimising environmental impact. Management interventions included conservation tillage and organic matter incorporation for soil biophysical health, reduced crop protection inputs and integrated pest management strategies for enhanced biodiversity and ecosystem functions, and intercropping, cover cropping and under-sowing to achieve more sustainable nutrient management. This system was compared directly with standard commercial practice in a split-field experimental design over a six-year crop rotation. The effect of the cropping treatment was assessed according to the responses of a suite of indicators, which were used to parameterise a qualitative multi-attribute model. Scenarios were run to test whether the integrated cropping system achieved greater levels of overall sustainability relative to standard commercial practice. Overall sustainability was rated high for both integrated and conventional management of bean, barley and wheat crops. Winter oilseed crops scored medium for both cropping systems and potatoes scored very low under standard management but achieved a medium level of sustainability with integrated management. In general, high scores for environmental sustainability in integrated cropping systems were offset by low scores for economic sustainability relative to standard commercial practice. This case study demonstrates the value of a &lsquo, whole cropping systems&rsquo, approach using qualitative multi-attribute modelling for the assessment of existing cropping systems and for predicting the likely impact of new management interventions on arable sustainability.

Root nodule bacteria were isolated from nodules on Mimosa pudica L. growing in neutral-alkaline soils from the Distrito Federal in central Brazil. The 16S rRNA gene sequence analysis of 10 strains placed them into the genus Rhizobium with the closest neighbouring species (each with 99 % similarity) being Rhizobium grahamii, Rhizobium cauense, Rhizobium mesoamericanum and Rhizobium tibeticum. This high similarity, however, was not confirmed by multi-locus sequence analysis (MLSA) using three housekeeping genes (recA, glnII and rpoB), which revealed R. mesoamericanum CCGE 501T to be the closest type strain (92 % sequence similarity or less). Chemotaxonomic data, including fatty acid profiles [with majority being C19 : 0 cyclo ω8c and summed feature 8 (C18 : 1ω7c/C18 : 1ω6c)], DNA G+C content (57.6 mol%), and carbon compound utilization patterns supported the placement of the novel strains in the genus Rhizobium. Results of average nucleotide identity (ANI) differentiated the novel strains from the closest species of the genus Rhizobium, R. mesoamericanum, R. grahamii and R. tibeticum with 89.0, 88.1 and 87.8 % similarity, respectively. The symbiotic genes essential for nodulation (nodC) and nitrogen fixation (nifH) were most similar (99-100 %) to those of R. mesoamericanum, another Mimosa-nodulating species. Based on the current data, these 10 strains represent a novel species of the genus Rhizobium for which the name Rhizobium altiplani sp. nov. is proposed. The type strain is BR 10423T (=HAMBI 3664T).

The common bean (Phaseolous vulgaris L.) is a grain legume functionally characterized by its capacity for symbiotic of biological nitrogen fixation. As such, it does not demand the application of synthetic nitrogenous fertilizer and can offer environmental benefits as part of holistic cropping systems. While common bean commodities are highly nutritious, commercial cultivation of this crop is declining in already-industrialized countries. However, recent interest of consumers towards diets that benefit environmental and personal health has rekindled commercial interest in legumes, including the common bean. The aim of this protocol is to identify agronomic practices that are capable of increasing the yield and quality of the common bean for use as food. To address this research question, published literature will be screened for inclusion on the basis of defined eligibility criteria to ensure data sources are selected in an objective and consistent manner. Consistency checks will be carried out for the title, abstract and full texts of the literature collated. The output is expected to be a summary of the knowledge available to maximize the productivity and quality of the common bean as food. This anticipated synthesis will be of utility for a wide range of value-chain stakeholders from farmers and consumers, to research scientists and policy makers.

To date, few attempts have been made to assess the impact of Rhizobium inoculation on N2 fixation and plant yield in soilless cultivations of common bean. In the present study, common bean (P. vulgaris L.) grown on an inert medium (pumice) was inoculated with either Rhizobium tropici CIAT899 or a commercial product containing a mix of N2-fixing bacteria, specifically rhizobia, and Azotobacter sp. The plants treated with both inoculants were supplied with nitrogen (N)-free (0% N) nutrient solution (NS) throughout the cropping period. A third treatment with non-inoculated plants, which were supplied with a standard (100% N) NS was applied as a control. Inoculation with R. tropici significantly increased the total number of root nodules (80 nodules per plant on average) in comparison with the other two treatments (nine nodules per plant on average). The supply of N-free NS restricted markedly both total plant biomass and pod yield, whereas the inoculation with R. tropici mitigated this effect. The aboveground tissues of plants fed with N-free NS contained appreciably less N than those fed with standard solution when they were inoculated with the commercial inoculant (1.7 vs. 29 mg·g−1 dry weight, respectively). The shoot total N concentration 45, 65, and 90 days after transplanting (32, 31, and 29 mg·g−1 dry weight, respectively) was not reduced by the supply of N-free NS when the plants were inoculated with R. tropici. This finding indicates that, at least from the first sampling date onward, the tissue N level was not a limiting factor for growth and yield in plants inoculated with R. tropici. The supply of N-free NS restricted appreciably the potassium (K), magnesium (Mg), and zinc (Zn) levels in the aboveground plant biomass, regardless of inoculation treatment. The impaired growth and yield in plants fed with N-free NS and inoculated with R. tropici is ascribed to both a N shortage at early growth stages and a reduced K+ uptake aimed at electrochemically balancing the anion-to-cation uptake ratio under conditions of no external NO3– supply.

Lathyrus linifolius L. (Reichard) Bässler (bitter vetch) is a fabaceous nitrogen (N) fixing species. A coloniser of low nutrient (N) soils it supports biodiversity such as key moth and butterfly species and its roots are known for their organoleptic and claimed therapeutic properties. Thus, the species has high potential for restoration, conservation, novel cropping and as model species. The latter owing to its genetic synteny with important pulse crops. However, regeneration and functional attributes of L. linifolius remain to be characterised. Seeds of L. linifolius were characterised using physical, colourimetric and chemical data. Ultrastructural and functional characterisation of the N fixing root nodules included immunolabelling with nifH-protein antibodies (recognising the N fixing enzyme, nitrogenase). Endosymbiotic bacteria were isolated from the root nodules and characterised phylogenetically using 16S rRNA, nodA and nodD gene sequeneces. L. linifolius yielded hetermorphic seeds of distinct colour classes: green and brown. Seed morphotypes had similar carbon:N ratios and were equally germinable (ca. 90%) after scarification at differing optimal temperatures (16 and 20°C, respectively). Brown seeds were larger and comprised a larger proportion of the seed batch (69%). L. linifolius root nodules appeared indeterminate in structure, effective (capable of fixing atmospheric N) and accommodated strains with high similarity to Rhizobium leguminosarum biovar viciae. The findings and rhizobial isolates have potential application for ecological restoration and horticulture using native seeds. Also, the data and rhizobial resources have potential application in comparative and functional studies with related and socio-economically important crops such as Pisum, Lens and Vicia.

A comparative analysis was carried out of published methods to assess seed viability using 2,3,5-triphenyltetrazolium chloride (TTC) based assays of seed batches. The tests were carried out on seeds of barley (Hordeum vulgare cv. Optic) as a model. We established that 10% [w/v] trichloroacetic acid (TCA)/methanol is superior to the acetone and methanol-only based methods: allowing the highest recovery of formazan and the lowest background optical density (OD) readings, across seed lots comprising different ratios of viable and dead seeds. The method allowed a linear-model to accurately capture the statistically significant relationship between the quantity of formazan that could be extracted using the method we developed and the seed temperature-response, and seed viability as a function of artificially aged seed lots. Other quality control steps are defined to help ensure the assay is robust and these are reported in a Standard Operating Procedure.

Myxospermous seeds become bound by mucilage upon hydration and this trait is ecologically important. Major impacts could be enhancing seed-soil contact and improving water retention, which we quantify in this study. Myxospermous or demucilaged seeds of Capsella bursa-pastoris L. Medik. (shepherd’s purse) were added to a test sandy clay loam at seed : soil densities of 5 and 10 % [w/w]. The soil water retention and hydraulic conductivity were assessed. Soil rheology was also assessed using extracted mucilage only amendment at 0.5 and 1 % [w/w]. Shepherd’s purse seeds increased soil water retention and reduced soil hydraulic conductivity for myxospermous and demucilaged seeds. Soil rheological properties (complex shear modulus, viscosity and yield stress) increased in response to seed mucilage addition, and became more pronounced as soil dried. The mucilage had greatest impact on the yield stress compared to the other rheology parameters. The densities of myxospermous and non-myxospermous seeds, and mucilage tested here reflect that may be found naturally in soil seedbanks. The findings provide the first evidence that the soil seedbank provided from a wild arable species may regulate the soil water retention and enhance soil stability, and that this capacity is greater for myxospermous seeds.

The outer surface of myxospermous seed coats contains mucilage which absorbs large amounts of water relative to its dry weight. Ecologically, the seed mucilage can affect seed germination and dormancy. Upon hydration, a large proportion of the seed mucilage is lost to the soil and the physics of soil-seed mucilage interactions has not been assessed. Towards that end, the dynamic rheological properties of mucilage extracted from Capsella bursa-pastoris L. Medik. (shepherd's purse) seeds were assessed as a function of mucilage concentration (1-10% (w/w)), temperature (0-80 ◦ C) and shear frequency (0.1- 100 rad s −1 ). The seed mucilage was shear thinning and was classified as a highly viscous "weak gel". The relationship between the viscoelastic parameters (viscosity, η ∗ , storage and loss modulus, Gand G �� , yield and flow stresses, τy and τf ) and mucilage concentration were well fitted by power law models. The values of η ∗ , Gand G �� increased as temperature increased above 40 ◦ C and were also slightly frequency dependent. The shepherd's purse seed mucilage is more viscous than that from other plant parts, such as fruits and roots. These properties highlight the possibility that seed mucilage may affect soil conditions and therefore present an additional facilitative ecological role (beyond that already reported, which directly affect seed biology); and this is discussed.

There is increasing pressure on the agricultural industry to maintain or increase production of high‐quality food while maintaining long‐term environmental sustainability. and policies and practices have been developed and implemented in an attempt to improve the sustainability and efficiency of arable farming and satisfy these potentially conflicting requirements. However, to the authors' knowledge, there has been no attempt to quantify whether new interventions have the desired effect on improving sustainability at a whole‐systems level. Most studies focus on one, or a few, elements of a specific system and therefore fail to account for trade‐offs and conflicts between the many different interacting components. Here, we propose a whole‐systems approach based on a suite of indicators for a complete and holistic assessment of the efficacy of policies to improve economic, environmental, and ecological sustainability.

The potential of biological nitrogen fixation (BNF) to provide sufficient N for production has encouraged re-appraisal of cropping systems that deploy legumes. It has been argued that legume-derived N can maintain productivity as an alternative to the application of mineral fertilizer, although few studies have systematically evaluated the effect of optimizing the balance between legumes and non N-fixing crops to optimize production. In addition, the shortage, or even absence in some regions, of measurements of BNF in crops and forages severely limits the ability to design and evaluate new legume-based agroecosystems. To provide an indication of the magnitude of BNF in European agriculture, a soil-surface N-balance approach was applied to historical data from 8 experimental cropping systems that compared legume and non-legume crop types (e.g., grains, forages and intercrops) across pedoclimatic regions of Europe. Mean BNF for different legume types ranged from 32 to 115 kg ha(-1) annually. Output in terms of total biomass (grain, forage, etc.) was 30% greater in non-legumes, which used N to produce dry matter more efficiently than legumes, whereas output of N was greater from legumes. When examined over the crop sequence, the contribution of BNF to the N-balance increased to reach a maximum when the legume fraction was around 0.5 (legume crops were present in half the years). BNF was lower when the legume fraction increased to 0.6-0.8, not because of any feature of the legume, but because the cropping systems in this range were dominated by mixtures of legume and non-legume forages to which inorganic N as fertilizer was normally applied. Forage (e.g., grass and clover), as opposed to grain crops in this range maintained high outputs of biomass and N. In conclusion, BNF through grain and forage legumes has the potential to generate major benefit in terms of reducing or dispensing with the need for mineral N without loss of total output.

The ability of wild indigenous legumes to form root nodules capable of biological nitrogen (N 2) fixation has rarely been demonstrated for species in natural ecosystems in large parts of Europe. In ...

†Background and Aims The duration of the plant life cycle is an important attribute that determines fitness and coexistence of weeds in arable fields. It depends on the timing of two key life-history traits: time from seed dispersal to germination and time from germination to flowering. These traits are components of the time to reproduction. Dormancy results in reduced and delayed germination, thus increasing time to reproduction. Genotypes in the arable seedbank predominantly have short time to flowering. Synergy between reduced seed dormancy and reduced flowering time would create stronger contrasts between genotypes, offering greater adaptation in-field. Therefore, we studied differences in seed dormancy between in-field flowering time genotypes of shepherd’s purse. †Methods Genotypes with early, intermediate or late flowering time were grown in a glasshouse to provide seed stock for germination tests. Secondary dormancy was assessed by comparing germination before and after darkincubation. Dormancy was characterized separately for seed myxospermy heteromorphs, observed in each genotype. Seed carbon and nitrogen content and seed mass were determined as indicators of seed filling and resource partitioning associated with dormancy. †Key Results Although no differences were observed in primary dormancy, secondary dormancy was weaker among the seeds of early-flowering genotypes. On average, myxospermous seeds showed stronger secondary dormancy than non-myxospermous seeds in all genotypes. Seed filling was similar between the genotypes, but nitrogen partitioning was higher in early-flowering genotypes and in non-myxospermous seeds. †Conclusions In shepherd’s purse, early flowering and reduced seed dormancy coincide and appear to be linked. The seed heteromorphism contributes to variation in dormancy. Three functional groups of seed dormancy were identified, varying in dormancy depth and nitrate response. One of these groups (FG-III) was distinct for earlyflowering genotypes. The weaker secondary dormancy of early-flowering genotypes confers a selective advantage in arable fields.

Wild arable plants can be an economic burden but they also support diverse arable food webs and contribute to valuable ecosystem functions. Th ese benefi ts may have been compromised over recent decades by declining weed diversity. Th e decline in wild arable plant diversity has been viewed predominantly in terms of species shifts a view that ignores the genetic and functional variation existing within species and the impact on ecological and evolutionary processes which this may have. To examine within-species diversity, ISSR markers were used in parallel with environmental and phenotypic characterisation, to investigate the population structure and diversity of Capsella bursa-pastoris (shepherd ’ s purse) from arable fi elds in the UK. Analysis of 338 ISSR products for 109 individuals from 51 accessions obtained from the seed banks of 33 arable fi elds showed that in-fi eld populations of shepherd’s purse were genetically diff erentiated between individuals, and among accessions and fi elds. In addition, cluster analysis identifi ed three genetically distinct regional-scale populations. Phenotypic variation was present at all scales of genetic diff erentiation, including the regional scale where populations diff ered in their key life-history traits: fl owering time, fecundity and dormancy. Genetic drift is proposed as a contributor to diff erentiation among genetically isolated but locally co-occurring accessions. In addition, the genetic and phenotypic variation in shepherd ’ s purse exhibited large scale, spatial trends and showed statistically signifi cant associations with cropping intensity and soil-pH. Th ese results suggest that adaptation as a result of selection by cropping practise and soil-pH has played a role in the ability of shepherd ’ s purse to colonise and persist in arable fi elds.

†Background and Aims Myxospermy is a term which describes the ability of a seed to produce mucilage upon hydration. The mucilage is mainly comprised of plant cell-wall polysaccharides which are deposited during development of those cells that comprise the seed coat (testa). Myxospermy is more prevalent among those plant species adapted to surviving on arid sandy soils, though its significance in determining the ecological fitness of plants is unclear. In this study, the first mathematical model of myxospermous seed mucilage expansion is presented based on seeds of the model plant species Capsella bursa-pastoris (shepherd’s purse). †Methods The structures underpinning the expansion process were described using light, electron and time-lapse confocal micrographs. The data and experimental observations were used to create a mathematical model of myxospermous seed mucilage expansion based on diffusion equations. †Key Results The mucilage expansion was rapid, taking 5 s, during which the cell mucilage volume increased 75-fold. At the level of the seed, this represented a 6-fold increase in seed volume and a 2.5-fold increase in seed surface area. These increases were shown to be a function of water uptake (16 g water g 21 mucilage dry weight), and relaxation of the polymers which comprised the mucilage. In addition, the osmotic pressure of the seed mucilage, estimated by assessing the mucilage expansion of seeds hydrated in solutions of varying osmotic pressure, was ‐0.54 MPa (equivalent to 0.11 M or 6. 6g L 21 NaCl). †Conclusions The results showed that the mucilage may be characterized as hydrogel and seed-mucilage expansion may be modelled using the diffusion equation described. The potential of myxospermous seeds to affect the ecological services provided by soil is discussed briefly.

Summary Arable weeds are believed to sustain disease outbreaks of the potato crop pathogen Tobacco Rattle Virus (TRV), which is particularly well-known for the costly damage it may cause to potato tubers. We describe a TRV-specific TaqManbased molecular-diagnostic quantitative RT-PCR method which showed that ecotypes of the widespread and common weed Cap- sella bursa-pastoris (shepherds purse) are highly sus- ceptible to TRV infection and may be suitable as indicator species of TRV presence in situ. Soils from two sites (S1 and S2), previously diagnosed as harbour- ing high levels of TRV, were the subjects of infection tests using C. bursa-pastoris and the susceptible model bait species Petunia x hybrida. TRV infection was only detected in all S1-soil, but in none of the plants grown in S2-soil. S1 soil had been treated annually with nemati- cide and herbicide, whilst continuing to cultivate TRV susceptible crops. S2 soil had been farmed for 5 years without the application of synthetic pesticides according to organic standards and had been sown with non-TRV susceptible crops in three out of the 5 years of the rotation. Our observations led us to question the current recommendations that: Weed control is important. Organic practices and set-aside may facilitate the re-introduction of TRV and ⁄ or the increase the distri- bution of the virus within a field. We suggest that more effective and less environmentally damaging crop pro- tection can be achieved using rotations that employ non- susceptible crops, in concert with management strategies that encourage crop-weed co-existence.

Summary • The transcriptome of an organism is its set of gene transcripts (mRNAs) at a defined spatial and temporal locus. Because gene expression is affected markedly by environmental and developmental perturbations, it is widely assumed that transcriptome divergence among taxa represents adaptive phenotypic selection. This assumption has been challenged by neutral theories which propose that stochastic processes drive transcriptome evolution. • To test for evidence of neutral transcriptome evolution in plants, we quantified 18 494 gene transcripts in nonsenescent leaves of 14 taxa of Brassicaceae using robust cross-species transcriptomics which includes a two-step physical and in silico-based normalization procedure based on DNA similarity among taxa. • Transcriptome divergence correlates positively with evolutionary distance between taxa and with variation in gene expression among samples. Results are similar for pseudogenes and chloroplast genes evolving at different rates. Remarkably, variation in transcript abundance among root-cell samples correlates positively with transcriptome divergence among root tissues and among taxa. • Because neutral processes affect transcriptome evolution in plants, many differences in gene expression among or within taxa may be nonfunctional, reflecting ancestral plasticity and founder effects. Appropriate null models are required when comparing transcriptomes in space and time.

Summary The arable plant Capsella bursa-pastoris is phenotypically variable in many life history traits, particularly time from germination to flowering. The hypothesis was investigated that, associated with this variation, there are differences in traits that influence plant quality for insect herbivores. Significant within-species variation was found in plant growth, leaf surface characteristics and tissue nutrient composition among 21 accessions of Capsella. Short flowering time plants exhibited slow vegetative growth, relatively large shoot nitrogen content, high leaf hair densities and differences in phloem composition, compared with long flowering time plants. Insect herbivore response to distinctive trait combinations was assessed on a subset of seven accessions using the phloem-feeding aphids Aphis fabae and Myzus persicae. Variation in aphid performance was small but significant, with 15–25% fewer nymphs produced on plant variants that exhibited greater tissue water content and low tissue C:N ratio (A. fabae) or on variants with less phloem nitrogen (M. persicae). The differential responses exhibited by the two aphid species to the test accessions confirmed that quantifying intraspecific plant variation is a necessary first step in understanding plant functional diversity and its impact on consumers in arable systems.

Testing of seed and grain lots is essential in the enforcement of GM labelling legislation and needs reliable procedures for which associated errors have been identified and minimised. In this paper we consider the testing of oilseed rape seed lots obtained from the harvest of a non-GM crop known to be contaminated by volunteer plants from a GM herbicide tolerant variety. The objective was to identify and quantify the error associated with the testing of these lots from the initial sampling to completion of the real-time PCR assay with which the level of GM contamination was quantified. The results showed that, under the controlled conditions of a single laboratory, the error associated with the real-time PCR assay to be negligible in comparison with sampling error, which was exacerbated by heterogeneity in the distribution of GM seeds, most notably at a small scale, i.e. 25 cm3. Sampling error was reduced by one to two thirds on the application of appropriate homogenisation procedures.

Agricultural intensification has led to a systematic erosion of the biodiversity in arable ecosystems. Despite this, densities of plant species in the seedbank of arable fields are still sufficient to provide the potential for recovery of the arable flora and associated fauna. Identification of management practices to achieve this, while minimising negative effects of weed competition on crop yield, requires a mechanistic understanding of functional diversity in arable systems. However, a review of the ecological, physiological and genetic characteristics of 66 representative UK arable weed species revealed major gaps in this knowledge for even the most common species. Even less is known about the degree of variation between individuals within these species that contributes to overall levels of functional diversity. Classification of organisms into functional groups on the basis of species-level taxonomy is inadequate to describe the functional diversity of a system, since variability in a particular physiological trait can be as great between individuals within a species as between species. We therefore propose an individual based approach to examine the functional attributes of arable plants that affect resource acquisition, partitioning and energy transfer through the food web. Capsella (shepherd's purse) is proposed as a key species that is widespread, ecologically important, and physiologically and genetically diverse. Current understanding of Capsella systematics is therefore reviewed and a methodological approach is described that establishes a foundation for studies of biodiversity and function in arable systems.

Globally, annual expenditure on ecological restoration of degraded areas for habitat improvement and biodiversity conservation is approximately $18bn. Seed farming of native plant species is crucial to meet restoration goals, but may be stymied by the disconnection of academic research in seed science and the lack of effective policies that regulate native seed production/supply. To illustrate this problem, we identified 1,122 plant species important for European grasslands of conservation concern and found that only 32% have both fundamental seed germination data available and can be purchased as seed. The "restoration species pool," or set of species available in practice, acts as a significant biodiversity selection filter for species use in restoration projects. For improvement, we propose: (1) substantial expansion of research and development on native seed quality, viability, and production; (2) open-source knowledge transfer between sectors; and (3) creation of supportive policy intended to stimulate demand for biodiverse seed.

During raspberry (Rubus ideaus L. cv Glen Clova) fruit ripening, endo-β-1,4-glucanase (EGase; EC 3.2.1.4) specific activity (per g fresh weight) increases approximately 15-fold. Highest activity was associated with the surfaces of the receptacles where the weakening abscission zones are located. Immunoblotting using antibodies raised against a bean abscission-EGase (ab.-EGase) identified a single protein of M r 52 kDa that was present only in ripe fruit and was most prominent in the receptacle. Using reverse transcription-polymerase chain reaction (RT-PCR), two 497-bp partial putative EGase clones were obtained from ripe receptacle mRNA (termed RI-EGL1 and 2) which share 53% amino acid identity. The more abundant RI-EGL1 was used to obtain its full length clone from a ripe receptacle cDNA library. The deduced amino acid sequence of RI-EGL1 was similar to other ab.-EGase sequences (ca 67%) and contained the conserved motifs present in all E2-class EGases. Northern analysis revealed that RI-EGL1 expression was limited to ripe-fruit receptacles. Application of the ethylene antagonist 1-methylcyclopropene (1-MCP) to green fruits indicated that endogenous ethylene accelerates raspberry abscission and increases both EGase activity and RI-EGL1 expression.

A structural analysis was conducted to determine whether glycoprotein-containing intercellular space occlusions are involved in medium-term regulation of O 2 diffusion in soybean (Glycine max) nodules. Alterations in O 2 diffusion were induced by a 3 h detopping treatment, and glycoprotein was immunolocalized with the monoclonal antibodies MAC236 and MAC265. Western blots of unstressed nodules revealed that these antibodies recognize antigens with two different molecular weights in soybean nodules. Tissue printing of halved nodules showed that both antigens were present in fresh nodules from control and 3 h detopped plants. The main localization appeared to be the inner cortex, but some immunolabelling also occurred in the infected region. ELISAs demonstrated a significant increase in total nodule concentration of intercellular glycoprotein following detopping, and cryosections of fresh nodules from this treatment also showed localization of antigens within the intercellular spaces of the infected region. The production of intercellular space occlusions in both the mid-cortex and infected regions after 3 h detopping was confirmed by light microscopy and silver-enhanced immunolabelling; cortical changes were quantified by image analysis techniques. Electron microscopy revealed that the occlusions within the infected region were less dense and less heavily labelled than those in the cortex. These results are discussed in relation to O 2 diffusion regulation in soybean nodules.

This study focuses on four raspberry (Rubus idaeus) genotypes from two different genetic backgrounds: cvs Glen Prosen and Glen Clova, bred at the Scottish Crop Research Institute (SCRI) and genotypes bred at Horticulture Research International (HRI), East Malling (EM), EM 4997 and EM 5007. The ripe fruit of each genotype pair were characterised subjectively by raspberry breeders as relatively firm or soft, respectively. Different stages of fruit development from each genotype were used to quantify fruit firmness, rates of ethylene evolution and ripening rate. Penetrometry data confirmed suspected firmness differences. Firmness correlated with rates of ethylene evolution. Rates of ethylene production also correlated with receptacle size. Storage of green fruits in 20 μl l -1 ethylene reduced fruit firmness, enhanced respiration rate and colour (anthocyanin) development and stimulated the development of cell wall hydrolase activities. However, during natural ripening in the field, fruit respiration rate declined, which indicates a non-climacteric ripening pattern. In drupelets, the activities of polygalacturonase (PG), pectin methylesterase (PME), Cx-cellulase (Cx) and β-galactosidase (β-gal.) increased substantially as ripening progressed. More detailed studies with ripe fruit of cv. Glen Clova indicated major isoforms of PG at pIs 3.3, 8.6 and 10.1; of PME at pIs 7.2, 8.5, 8.7, 8.8; of Cx at pI 2.4; and of β-gal. at pIs 6.3 and 6.7.

Plant polygalacturonase-inhibiting proteins (PGIPs) inhibit endo-polygalacturonases (endo-PGs) released by invasive fungi. Two potential PGIP cDNAs have been cloned from raspberry (Rubus idaeus). PGIP1 corresponds to a full-length PGIP cDNA with a high degree of identity with previously isolated genes and maintains all the characteristic features of PGIP peptides. A genomic fragment of PGIP1 identifies a single 243 bp intron which is efficiently spliced out of the PGIP1 pre-mRNA transcript. PGIP2 contains a frame shift mutation which would lead to the loss of 105 amino acids off the C-terminus. Contrary to PGIP activity levels in raspberry (Johnston et al., 1993), expression analysis detected PGIP1 at equal levels throughout fruit development from closed flower, through to ripe fruit.

The tropical wetland legume Sesbania rostrata Brem. produces nitrogen-fixing stem nodules which are green and contain chlorophyll, the chloroplasts being concentrated in a hand in the inner and mid-cortex close to the nitrogen-fixing cells. The photosystem II thylakoid membrane proteins D1, D2 and PsbO, which are essential for photo-synthetic O2 evolution, were shown by immunoblotting to be present in extracts of leaves and stem nodules. Immunogold labelling confirmed their presence on stem nodule thylakoids and showed that labelling was most intense in well-developed chloroplasts in the mid-cortex and least intense in the smaller, less-abundant chloroplasts adjacent to the nitrogen-fixing cells. Concentrations of the oxygen-carrying protein leghaemoglobin (Lb) did not differ between stem and S. rostrata root nodules, and Lb was localized in bacteroid-containing cells, including those immediately adjacent to the cortex, in both nodule types. Moreover, nitrogenase component 2 was localized in bacteroids within the outermost layers of infected cells, suggesting that a low pO2 was maintained, despite the nearby chloroplasts. Nodule extracts examined by ELISA and immunoblots, using the monoclonal antibody MAC265, showed greatly enhanced expression of a 139 kDa glycoprotein in stem compared to root nodules. Immunogold labelling showed that material containing the MAC265 antigen occluded intercellular spaces, and was present in cell walls, throughout the cortex of stem nodules (particularly in the chloroplasl-rich inner and mid-cortex), but was considerably less evident in root nodules.

The oxygen diffusion resistance of Lupinus albus (L.) cv. Multolupa root nodules was increased by subjection to short-term stresses; lowering rhizosphere temperature from 25 to 16 °C (2 h), detopping plants (3 h), darkening plants (21 h) or exposing roots to 20 mol m-3 KN03 for 2, 4 or 6 d. Microscopic observations and measurements showed that this resulted in the area of open intercellular spaces within the inner cortex being reduced due to both cell expansion and increased production of an occluding glycoprotein. Electrophoretic and Western Blot analysis using the monoclonal antibodies MAC236 and MAC265 showed two distinct glycoprotein antigens with molecular weights of 240 and 135 kDa, respectively. Both antigens are localized within intercellular spaces of the inner cortex. The amount of glycoprotein was determined using either ELISA, with MAC265, or quantification of immunolabelling with MAC236. This immunolabelling also localized the glycoprotein within globules adhering to the inside of the inner cortical cell walls.

An enzyme-linked immunosorbant assay (ELISA) method based on a monoclonal antibody (MAC236) is described in which relative amounts of an intercellular glycoprotein were quantified in extracts of whole legume nodules. This glycoprotein has recently been shown to be an important component of the cortical oxygen diffusion barrier. The ELISA method is demonstrated on three examples of soybean (Glycine max L. Merr.) nodule systems which have been the subject of previously published investigations: (a), cv. Clarke inoculated with Bradyrhizobium japonicum RCR3442, nodulated root systems of which were subject to 10, 21 or 40% oxygen continuously for 28 d; (b), cv. Bragg and its supernodulating mutant derivative (nts382) inoculated with Bradyrhizobium japonicum USDA110; (c), cv. Clarke inoculated with Bradyrhizobium japonicum RCR3442 or RCR3407. ELISA results are related to oxygen diffusion characteristics defined in previous publications and show that increases in the amount of glycoprotein present correlated with increases in supra-ambient (40%) levels of rhizosphere pO2, in minimum gas diffusion resistance and in speed of diffusion barrier response. Area data of component parts of nodule inner cortices suggest that diffusion resistance control under sub-ambient (10%) oxygen levels also involves cell expansion. The amount of MAC236 antigen in nodules is affected by both host plant genotype and rhizobial strain and the latter also appears to be involved in determining the morphological development of the nodule inner cortex.

A protocol is described which allows the detection of transglycosylase isoenzyme activity. Crude extracts of cauliflower (Brassica oleracea var. botrytis) florets were treated with 1 M sodium chloride, filtered through cellulose acetate, dialysed, concentrated and subjected to isoelectric focusing under non-denaturing conditions in a polyacrylamide gel. After electrophoresis, the gel was overlaid with a test paper impregnated with a mixture of high-Mr xyloglucan and a sulphorhodamine-conjugated oligosaccharide of xyloglucan. Transglycosylation caused the production of sulphorhodamine-labelled polysaccharide, which remained bound to the test paper after prolonged washing in water, revealing eight fluorescent bands corresponding to XET isoenzymes with pI values of 8.8, 8.6, 7.8, 7.6, 7.3, 7.1, 6.7 and 6.6. Copyright © 1999 John Wiley & Sons, Ltd.

The implementation of co-existence in the commercialisation of GM crops requires GM and non-GM products to be segregated in production and supply. However, maintaining segregation in oilseed rape will be made difficult by the highly persistent nature of this species. An understanding of its population dynamics is needed to predict persistence and develop potential strategies for control, while to ensure segregation is being achieved, the production of GM oilseed rape must be accompanied by the monitoring of GM levels in crop or seed populations. Heterogeneity in the spatial distribution of oilseed rape has the potential to affect both control and monitoring and, although a universal phenomenon in arable weeds and harvested seed lots, spatial heterogeneity in oilseed rape populations remains to be demonstrated and quantified. Here we investigate the distribution of crop and volunteer populations in a commercial field before and during the cultivation of the first conventional oilseed rape (winter) crop since the cultivation of a GM glufosinate-tolerant oilseed rape crop (spring) three years previously. GM presence was detected by ELISA for the PAT protein in each of three morphologically distinguishable phenotypes: autumn germinating crop-type plants (3% GM), autumn-germinating ‘regrowths’ (72% GM) and spring germinating ‘small-type’ plants (17% GM). Statistical models (Poisson log-normal and binomial logit-normal) were used to describe the spatial distribution of these populations at multiple spatial scales in the field and of GM presence in the harvested seed lot. Heterogeneity was a consistent feature in the distribution of GM and conventional oilseed rape. Large trends across the field (50 × 400 m) and seed lot (4 × 1.5 × 1.5 m) were observed in addition to small-scale heterogeneity, less than 20 m in the field and 20 cm in the seed lot. The heterogeneity was greater for the ‘regrowth’ and ‘small’ phenotypes, which were likely to be volunteers and included most of the GM plants detected, than for the largely non-GM ‘crop’ phenotype. The implications of the volunteer heterogeneity for field management and GM-sampling are discussed.

Contains fulltext : 35876pub.pdf (Publisher’s version ) (Closed access) Laser photoacoustic spectroscopy continuously quantified the ethylene (C2H4) produced by strawberry flowers and fruits developing in planta. C2H4 was first detected as flower buds opened and exhibited diurnal oscillations (to approximately 200 pl flower(-1) h(-1)) before petal abscission. Exogenous application of silver thiosulphate (STS) to detached flowers inhibited petal abscission and flower senescence. In fruit, C2H4 production was maintained at a 'low level' (10-60 pl fruit(-1) h(-1)) until fruit expanded when levels increased in a diurnal pattern (to 200 pl fruit(-1) h(-1)). After expansion, C2H4 production declined to a low level until fruit attained the red-ripe stage for at least 24 h. After this time, C2H4 levels increased linearly (no diurnal fluctuation) to approximately 1 nL fruit(-1) h(-1). Twenty-four hours after the re-initiation of C2H4 production by red fruit, CO2 levels increased approximately three-fold, indicative of a respiratory climacteric. STS applied to fruits developing in planta and dissected fruit parts ex situ established that C2H4 production is regulated by negative feedback until fruits had expanded. The C2H4 produced by red-ripe fruit was regulated by positive feedback. Anti-1-amino-cyclopropane-1-carboxylic acid oxidase IgG localization identified immunoreactive antigens of 40 and 30 kDa (M-r) within the fruit achenes of expanding and red-ripe fruit. Analysis of dissected fruit showed that seed C2H4 accounts for 50% the C2H4 that is detectable from ripe fruit.