Summary: This review discusses the use of agronomic management practices to enhance crop stress resilience to climate stress through the modulation of natural plant growth regulatory pathways. The use of biostimulants or plant hormones to improve crop resilience is subject to strict regulatory oversight if changes in the regulation of plant growth are implied. Climate change is a major threat to crop potential and is characterized by both long‐term shifts in temperature and precipitation patterns as well as increased occurrence of extreme weather events, posing an immediate threat to agriculture. Breeding and exogenous inputs have been used to enhance cropping system resilience, although these management practices are either too slow or constrained by cost and availability, to address rapidly emerging climate challenges. Exogenous biostimulants, microbials and plant hormones have shown great promise as novel mechanisms to optimize natural plant resilience, resulting in immediate but non‐permanent improvements in plant responses to climate‐induced stresses, representing a powerful but underexplored approach to enhance crop productivity under climate stress. The use of these exogenous inputs is, however, constrained by outdated and scientifically unsound regulations that consider any such modification as pesticidal in nature. The failure to modernize regulatory frameworks for the use of biostimulants in agriculture will constrain the development of safe effective tools and deprive growers of means to respond to climate change. Here, we discuss the scientific rationale for eliminating the regulatory barriers governing biostimulants or products that modulate plant regulatory networks and propose a framework for enabling legislation to strengthen cropping system resilience.

Five molecules at the energy-chemistry nexus, their position in the planetary boundary framework and Anthropocene-spurred interdisciplinary connections between chemistry, social sciences, and humanities to help define sustainability-driven research.

Zinc oxide (ZnO) is an attractive semiconductor material for photocatalytic applications, owing to its opto-electronic properties. Its performances are, however, strongly affected by the surface and opto-electronic properties (i.e., surface composition, facets and defects), in turn related to the synthesis conditions. The knowledge on how these properties can be tuned and how they are reflected on the photocatalytic performances (activity and stability) is thus essential to achieve an active and stable material. In this work, we studied how the annealing temperature (400 °C vs. 600 °C) and the addition of a promoter (titanium dioxide, TiO₂) can affect the physico-chemical properties of ZnO materials, in particular surface and opto-electronic ones, prepared through a wet-chemistry method. Then, we explored the application of ZnO as a photocatalyst in CO₂ photoreduction, an appealing light-to-fuel conversion process, with the aim to understand how the above-mentioned properties can affect the photocatalytic activity and selectivity. We eventually assessed the capability of ZnO to act as both photocatalyst and CO₂ adsorber, thus allowing the exploitation of diluted CO₂ sources as a carbon source.

Increasing the photocatalytic efficiency of earth-abundant wide-bandgap semiconductors is of high interest for the development of cheap but effective light-driven chemical conversion processes. In this study, the coupling of ZnO and TiO₂ with low contents of the rare-earth Ce species aimed to assess the photo-catalytic performance of the two semiconductors (SC). Structural and optical characterizations were performed to estimate the effect of the different interactions between Zn²⁺, Ti⁴⁺ and Ce⁴⁺ ions, and how the photo-responsive behaviour of Ce-Ti and Ce-Zn composites was affected. Therefore, photo-catalytic tests were performed for all Ce-modified SC to assess both their photo-oxidative and photo-reductive properties. Amongst all the tested materials, only Zn-based samples resulted in being suitable for the photo-oxidation of the methylene blue (MB) organic pollutant in a synthetic-dependent fashion.