Effects of carbon dioxide enrichment and environmental factors on photosynthesis, growth and yield and their interaction in cucumber: a meta-analysis

Despite the ongoing increase in atmospheric carbon dioxide concentrations, these levels remain well below the optimal threshold for cucumber growth and development. In addressing the challenges posed by climate change to agricultural production, the use of carbon dioxide enrichment (eCO ₂ ) has become increasingly widespread in order to meet global demand for cucumbers. Nevertheless, the impact of eCO ₂ and environmental factors on cucumber growth remains to be elucidated. In this study, we conducted a meta-analysis of 73 research papers on eCO ₂ in cucumbers was conducted, and their photosynthesis, growth, and yield were analysed. In summary, under conditions of elevated CO ₂ levels, the net photosynthetic rate, biomass, and yield of cucumbers exhibited a marked increase of 56.31%, 27.75%, and 21.98%, respectively. Concurrently, stomatal conductance and transpiration rate exhibited a decline of 36.07% and 30.42%, respectively. In the context of the implementation of eCO ₂ at varying levels within a production environment, the prevailing recommendation pertains to the range of 800-1200 ppm. It is advised that this be integrated with elevated light intensity, augmented temperature, suitable humidity levels, and a sufficient supply of fertiliser to achieve a synergistic effect. The findings of this study contribute to enhancement of environmental control in the context of greenhouse cultivation of cucumber in response to climate change, as well as promoting the green and sustainable development of the cucumber industry.