Green Conversations: Harnessing Plant Communication to control growth light intensity.

Controlled Environment Agriculture (CEA) delivers increased crop production per unit land, contributing to resilient food systems amidst challenges of climate change, population growth and urbanization. However, high energy costs associated with lighting impose substantial barriers to the widespread adoption of CEA. While light is indispensable for growth, critically its utilization by crops throughout the photoperiod remains sub-optimal, reducing photosynthetic efficiency and wasting energy. Here we have developed and demonstrated a novel real-time plant bio-feedback system that enables crops to directly communicate optimal lighting requirements. Continuous non- invasive monitoring of photochemistry elicited decreased demand for light by basil at the end of the photoperiod. Our innovative approach increased yield by 10% and reduced energy consumption per unit fresh mass by 18%, delivering a 201gCO2 gFW-1 reduction in carbon footprint. Application of this technique at scale can revolutionise resource management of CEA, reinvigorating the productivity, profitability and sustainability of this food industry. Author ContributionsJS & TL: designed the experiments; JS, PD and PK: performed all physiology experiments and data acquisition and carried out data analyses. TL, JS, PD and TH wrote the MS and all authors commented on the MS. One-sentence summaryChlorophyll fluorescence measurements of photosynthetic efficiency can be used to control growth light intensity in real time, optimising crop performance and energy use.