The involvement of ethylene in root architectural responses to phosphorus availability was investigated in common bean (Phaseolus vulgaris L.) plants grown with sufficient and deficient phosphorus. Although phosphorus deficiency reduced root mass and lateral root number, main root length was unchanged by phosphorus treatment. This resulted in decreased lateral root density in phosphorus‐deficient plants. The possible involvement of ethylene in growth responses to phosphorus deficiency was investigated by inhibiting endogenous ethylene production with amino‐ethoxyvinylglycine (AVG) and aerating the root system with various concentrations of ethylene. Phosphorus deficiency doubled the root‐to‐shoot ratio, an effect which was suppressed by AVG and partially restored by exogenous ethylene. AVG increased lateral root density in phosphorus‐ deficient plants but reduced it in phosphorus‐sufficient plants. These responses could be reversed by exogenous ethylene, suggesting ethylene involvement in the regulation of main root extension and lateral root spacing. Phosphorus‐deficient roots produced twice as much ethylene per g dry matter as phosphorus‐sufficient roots. Enhanced ethylene production and altered ethylene sensitivity in phosphorus‐deficient plants may be responsible for root responses to phosphorus deficiency.

There is need to better understand the trends and future challenges influencing the marine and coastal environments and identify the opportunities to develop innovative sustainability-oriented solutions to address these. Alongside mainstream decision support tools used in environmental management and conservation sciences, foresight techniques provide comprehensive and well-rounded information and knowledge about likely developments in the long-term future. This study uses a horizon scanning exercise to explore emerging signals and trends of future developments and innovation for the sustainable development of the blue economy looking towards 2030. It derives a series of global developments, challenges and opportunities relating to the blue economy from a review of high-level international reports and studies. Through a workshop conducted with 29 scientists and researchers based in maritime universities in six countries in Europe, the study identifies and prioritizes emerging signals and trends considered of high impact for a sustainability transition. The outputs include a synthesis of 11 global developments in the blue economy and 7 cross-cutting trends and trend projections. These may be valuable to marine scientists as a source of inspiration for a future research agenda or can be used as evidence for decision- and policymakers to deal with future uncertainties about the growth of the blue economy.