An improved approach for estimating root elongation rate from penetrometer resistance and macropore porosity on a silty clay loam soil

The role of macropores is often ignored in classical models for predicting root elongation using soil penetrometer resistance (PR). In this study, we propose an empirical model that includes the effects of macropores and PR on maize (Zea mays L.) root elongation rate (RER) and compare its performance with three previous models. Undisturbed soil cores were collected from an 11-yr tillage experiment (including no-tillage and conventional tillage systems) in Northeast China. For each soil core, soil bulk density (BD), penetrometer resistance (PR), air-filled porosity (AFP), and pore size distribution from water release characteristics, and RER of maize seedlings at a matric potential of \u100000 20 kPa were determined. Results showed that RER negatively correlated with BD, PR, and the volume of ε60 (the volume of pores greater than 60 μm) (P 60 μm), performed better in predicting RER than the previous models, with a root mean square error (RMSE) of 0.36. The new model is useful in simulating maize root distribution under field conditions

Socio-economic factors constrain climate change adaptation in a tropical export crop

Climate change will alter the geographical locations most suited for crop production, but adaptation to these new conditions may be constrained by edaphic and socio-economic factors. Here we investigate climate change adaptation constraints in banana, a major export crop of Latin America and the Caribbean. We derived optimal climatic, edaphic and socio-economic conditions from the distribution of intensive banana production across Latin America and the Caribbean, identifed using remote sensing imagery. We found that intensive banana production is constrained to low-lying, warm aseasonal regions with slightly acidic soils, but is less constrained by precipitation, as irrigation facilitates production in drier regions. Production is limited to areas close to shipping ports and with high human population density. Rising temperatures, coupled with requirements for labour and export infrastructure, will result in a 60% reduction in the area suitable for export banana production, along with yield declines in most current banana producing areas

Starship giant transposable elements cluster by host taxonomy using kmer-based phylogenetics

Starships are a recently established superfamily of giant cargo-mobilising transposable elements in the fungal subphylum Pezizomyotina (phylum Ascomycota). To date, Starship elements have been identified up to ∼700 Kbp in length and carrying hundreds of accessory genes, which can confer both beneficial and deleterious traits to the host genome. Classification of Starship elements has been centred on the tyrosine recombinase gene that mobilises the element, termed the captain. We contribute a new perspective to Starship classification by using an alignment-free kmer-based phylogenetic tree building method, which can infer relationships between elements in their entirety, including both active and degraded elements and irrespective of high variability in element length and cargo content. In doing so we found that relationships between entire Starships differed from those inferred from captain genes and revealed patterns of element relatedness corresponding to host taxonomy. Using Starships from Gaeumannomyces species as a case study, we found that kmer-based relationships correspond with similarity of cargo gene content. Our results suggest that Starship-mediated horizontal transfer events are frequent between species within the same genus but are less prevalent across larger host evolutionary distances. This novel application of a kmer-based phylogenetics approach overcomes the issue of how to represent and compare highly variable Starships elements as a whole, and in effect shifts the perspective from a captain to a cargo-centred concept of Starship identity. SUMMARY We applied a kmer-based phylogenetic classification approach to giant Starship cargo-mobilising elements from species across the Pezizomycotina (Ascomycota, Fungi). We found Starship elements to frequently cluster according to host taxonomy, suggesting horizontal transfer of elements is less common across larger evolutionary distances. Kmer-based phylogenetics approaches show promise for both element classification and to inform our understanding of the evolution of Starships and other giant cargo-mobilising elements

Biomes Affect Baking Properties and Quality Parameters of Different Wheat Genotypes

Wheat (Triticum aestivum L.) is predominantly cultivated in the Atlantic Forest biome. However, the recent expansion of agricultural frontiers in Brazil has led to its introduction into the Savannah biome. The commercial and technological quality parameters of wheat are determined by the interaction between genotype and growing environment. In this context, the objective of this study was to evaluate the effects of six wheat genotypes cultivated in five distinct environments, three located in the Atlantic Forest biome and two in the Savannah biome. The results demonstrated that environmental conditions significantly influenced protein and starch contents, which in turn affected hectoliter weight and falling number. On the other hand, genotypic variation had a marked effect on thousand-grain weight, colorimetric parameters (L* and b*), water and sodium retention capacities, dough tenacity and extensibility, as well as gluten strength. Wheat genotypes cultivated in the Savannah biome exhibited superior baking performance and technological quality, characterized by elevated starch content, enhanced gluten strength (with the exception of the genotype Feroz), and greater dough tenacity (except for the genotype Guardião), when compared to those cultivated in the Atlantic Forest biome. These results highlight the potential for identifying more sustainable cultivation environments, considering the different biomes, for the production of wheat with superior nutritional and technological quality, promoting the efficient use of natural and economic resources throughout the production cycle

Towards a sustainable phosphorus network in Africa

Global collaborative action for sustainable management of phosphorus is vital to ensure food production and the protection of water quality. This requires balancing competing phosphorus demands and a growing population through coordinated actions at local, national, regional and international scales. Phosphorus is mainly used in the agricultural sector as an essential nutrient for plant growth and animal feed. It is also used to a lesser extent in the food industry as an additive, as an additive in steel production and most recently in the production of lithium batteries for electric cars. Phosphorus is a finite resource, making its sustainable use a global priority. Yet, losses from the global phosphorus system risk pollution of aquatic ecosystems associated with biodiversity loss and human health risks associated with harmful algal blooms. While phosphorus supplies from reserves are not of immediate concern, there is nonetheless a need to ensure sustainable phosphorus use at the global level. Africa’s use of phosphorus fertilisers is sub-optimal, with a reported decline in phosphorus fertiliser use of about 233 % by the turn of the 21st century, and remains low. The Sustainable Phosphorus Summit (SPS) is the only global conference series supporting discourse on phosphorus sustainability spanning across the academic, agriculture, environmental, wastewater, policy and industry sectors. Since its inception in 2010, the SPS series has been held every 2–4 years on all continents – except Africa. The hosting of the 8th SPS (SPS8) in Accra, Ghana, will present an opportunity to set the agenda for sustainable phosphorus management in Africa, and to place African contexts into the global discussion. Being organised by different teams led by an African Local Organising Committee, SPS8 aims to pave the way towards the establishment of an African Sustainable Phosphorus Network, serving as a platform for collaboration, networking and knowledge co-creation and exchange to ensure sustainable phosphorus use in the region and beyond. Sustainable phosphorus management in Africa is feasible in the medium to long-term, with a focus on ensuring adequate phosphorus fertiliser availability, access and use, while minimising the environmental impacts from losses by matching soil-crop phosphorus needs and enhancing circular phosphorus use systems, and informing ecosystem recovery planning

Biomass burning smoke pollution stimulates painted lady butterflies (Vanessa cardui L.) to increase flight speed

Smoke from biomass burning significantly degrades air quality due to high concentrations of particulate matter (PM2.5) and trace gases. While the ecological and health impacts of smoke pollution are well documented, its effects on insect migration remain poorly understood. In this study, we conducted two experiments to investigate the flight performance of Vanessa cardui butterflies under varying smoke conditions and identify the mechanisms influencing their behaviour. Butterflies were tethered to flight mills (TFMs) for 6 h, during which flight speed, distance, and duration were recorded across clean-air conditions and three levels of PM2.5 concentrations. Statistical analysis revealed that flight speed increases significantly as smoke concentration increases, although the increased range decreases. At a mean PM2.5 concentration of 120 μg m−3, flight speed increased by 52 % compared to clean-air conditions. To determine whether particulate matter was driving this response, individuals were exposed to smoke with and without particulates. In smoke with particulates retained, butterflies exhibited nearly double the flight speed compared to filtered smoke, indicating that particulates play a key role in altering flight behaviour. Scanning electron microscopy revealed significant deposition of smoke particulates on the antennae and abdomen, suggesting a sensory or physical response triggering accelerated flight. We interpret these findings as evidence that Vanessa cardui accelerates flight in smoky environments as an escape response. This study highlights the remarkable sensitivity of butterflies to smoke pollution and provides novel insights into the ecological consequences of biomass burning, particularly its potential impacts on insect behaviour and migration dynamics

Induction of α-amylase and endosperm-imposed seed dormancy: two pioneering papers in gibberellin research

Main conclusion Two papers with quite different objectives established protocols that proved pivotal for future work on the role of gibberellins in seed germination Abstract: In their paper published in 1967, Russell Jones and Joseph Varner (Planta 72: 155-161) developed a bioassay based on induction of α-amylase activity in barley embryo-less half-seeds that was specific for bioactive gibberellins. The induction of α-amylase in the aleurone of barley and other cereals was to become the experimental system of choice to study gibberellin signalling. However, despite much progress in identifying the molecular events linking gibberellin action and α-amylase gene expression, in many cases their role in the process is still unclear. In 1987 Steven Groot and Cees Karssen (Planta 171:525-531) showed that germination of tomato seeds was limited by the ability of the radicle to penetrate the surrounding layers, with the endosperm forming the major barrier. They used a modified needle attached to a tensiometer to measure the force required to break through the endosperm. While in wild-type seeds a factor from the embryo, assumed to be gibberellin, promoted breakdown of the endosperm, gibberellin-deficient seeds required an external supply of the hormone to weaken the endosperm or for it to be mechanically disrupted for germination to occur. The paradigm of seed germination being physically restricted by surrounding layers and the role of gibberellin in weakening these tissues has been confirmed in many eudicot species. Gibberellin signalling induces the production of cell-wall loosening enzymes in the micropylar endosperm adjacent to the radicle, but it is unclear whether or not this is a direct response. In both eudicot and monocot systems, there is still much to learn about the role of gibberellin signalling in germination

Active navigation and meteorological selectivity drive insect migration patterns through the Levant

Insect migration is crucial to many natural processes and human activities, yet large-scale patterns remain poorly understood. On the Mediterranean’s eastern shores lies a 70 km-wide stretch of hospitable habitat between the sea and the Arabian Desert, which we term the Levantine Corridor, extending ~400 km south from Turkey to the edge of the Sahara. We deployed 7 biological radars over 8 years, recording 6.3 million individual large insects (>10 mg) and revealing an important migration route at the nexus of three continents, with over 700 million large insects estimated to cross annually. However, a comparison with European insect migration flows suggests that Levantine insect fluxes are lower than at higher latitudes, challenging the conjecture that the Levantine Corridor acts as a funnel for insect migration as reported for birds. Insects showed strong migratory directionality differing from prevailing wind direction in spring and autumn, with mass migrations separated by periods of weaker movements. Migration intensity strongly depended on the weather, with insects preferentially migrating in seasonally beneficial tailwinds when possible and in warmer temperatures. The study reveals an unexplored insect migration route with implications for food webs, pollination, disease transmission, pest outbreaks and species invasions across West Asia, East Europe and Northeast Africa

Trade-offs associated with changing cropping patterns in semi-arid areas of Morocco

We developed a model-based framework to support land-use and management decision-making. This framework integrates data and models to support an assessment of scenarios related to crop choices and irrigation management. The framework includes the IPCC models to describe nutrient losses, the Rothamsted carbon model to predict soil organic carbon and Cornel's Environmental Impact Quotient model to predict impacts from pesticides (fungicides, herbicides and insecticides). We used Monte Carlo simulations to quantify model uncertainties. Shaded arrays were used to communicate the uncertainties to end users of the framework. We parameterised our framework to explore outcomes for an irrigated agricultural area in a semi-arid region of Morocco. We used the framework to explore scenarios that were codesigned with farming stakeholders. The scenarios related to crop diversification, and to recent policies on the expansion of olive cultivation and the adoption of efficient irrigation technologies. For the outcomes considered (production, profitability, soil carbon, nutrient losses, pesticide impacts), there were clear trade-offs associated with the cropping system choice. Compared to the baseline scenario of rotated crops, olive production led to greater carbon sequestration (average 4 % increase by doubling olive production), reduced water use (average 3 % reduction by doubling olive production), and reduced emissions (average 42 % reduction by doubling olive production) but was less profitable and provided fewer edible calories. Additionally, olive cultivation was associated with higher environmental impacts from pesticides. Diversified systems, while less profitable, were associated with less harmful pesticide use. Drip irrigation was associated with positive outcomes for profit (average 23 % increase), water use (average 13 % reduction in water use), and reduced nitrogen leaching (average 40 % reduction) with negligible changes in other metrics. However, we did not account for factors associated with increased groundwater depletion. We conclude that such frameworks are a useful means for policy-stakeholders to explore the outcomes of their decisions, thereby, helping to minimise unintended consequences

Variation in suppression of black-grass by modern and ancestral cereal root exudates

This study aimed to determine the variability of hexaploid wheat Triticum aestivum, ancestral diploid wheat T. monococcum, and rye Secale cereale root exudates, in their potential to inhibit the arable weed black-grass Alopecurus myosuroides, informed by precedent for variability in resistance to herbivorous pests and pathogens across this cereal germplasm. As benzoxazinoids are suggested to play a role in resistance against these stressors, and also in allelopathy, we also aimed to identify these compounds in collected root exudates. We conducted in vitro and glasshouse bioassays to determine the efficacy of a wide range of crude cereal root exudates and their constituent compounds in inhibiting black-grass in both axenic and biologically-active media. LC-MS analysis was used to characterise the constituents of these exudates and their differences between hexaploid wheat, diploid wheat and rye. Root development of black-grass was suppressed to various degrees by crude root exudates of this diverse range of cereals, with the most effective being S. cereale var. Edmondo, and T. monococcum MDR037. Benzoxazinoid content of root exudates appeared to vary, with ancestral wheat lines and rye exuding fewer of these compounds than hexaploid wheat, but with greater variability between lines. Co-culture with T. aestivum var. Gravity was significantly inhibitory to early shoot growth and biomass of black-grass seedlings, but individual benzoxazinoids had no effect on black-grass in the same system. These data provide evidence that cereal-black-grass interactions are influenced by root exudates, but that their effects cannot be replicated through the direct application of individual constituent compounds