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The leaves of Festuca arundinacea can excrete cadmium (Cd) out onto the leaf surface, leading to a bio-pump phytoremediation strategy based on "root uptake—root-to-leaf translocation—leaf excretion". However, the bio-bump efficiency of soil Cd is a limiting factor for the implementation of this novel technology. Bio-bump remediation involves the bioprocess of plant root uptake from soil, root-to-leaf translocation, and leaf hydathode excretion. Here we show the significant effects of phytohormones in regulating the bio-pump phytoextraction efficiency. The results showed that salicylic acid and ethylene enhanced the whole process of Cd root uptake, root-to-leaf translocation, and leaf excretion, promoting the bio-pump phytoextraction efficiency by 63.6% and 73.8%, respectively. Gibberellin also greatly promoted Cd translocation, leaf excretion, and phytoextraction, but did not significantly impact Cd root uptake. Our results indicate that salicylic acid and ethylene could be recommended to promote bio-pump phytoextraction efficiency in F. arundinacea. Gibberellin might be used for a short-term promotion of the leaf Cd excretion. [Display omitted] • Phytohormones performed different impacts on bio-pump phytoextraction. • Salicylic acid promoted bio-pump phytoextraction efficiency by 63.6%. • Ethylene promoted bio-pump phytoextraction efficiency by 73.8%. • Gibberellin promoted leaf Cd excretion but had no impact on root uptake. • Auxin inhibited bio-pump phytoextraction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Urban food waste—green infrastructure nexus is feasible. • Food waste digestate significantly promoted green roof plant growth and functions. • Food waste digestate is better than digestate biochar in green roof promotion. • 20% performed better than 10% both in digestate and digestate biochar. Waste—Green Infrastructure Nexus is crucial to mitigate carbon emissions in waste disposal and promote eco-functions of green infrastructure in a circular bio-economy. Our purpose is to verify the feasibility of the nexus via "food waste anaerobic digestion — digestate/digestate biochar — green roof promotion". The results found that food waste digestate and digestate biochar significantly promoted green roof plant growth, evapotranspiration, rainwater retention, runoff reduction, and prevention of nutrient leaching. Digestate treatments were better than digestate biochar for the green roof promotion. The promotion ranked consistently with 20 % digestate > 10 % digestate > 20 % digestate biochar > 10 % digestate biochar > control in stolon growth, leaf emergence, branching of Paspalum vaginatum , green roof establishment, rainwater retention, runoff reduction, and the leaching of nitrogen, phosphorus, potassium. This study demonstrated that food waste could be regenerated to promote urban green infrastructure to form a circular bio-economy by the Waste—Green Infrastructure Nexus. [ABSTRACT FROM AUTHOR]