MAPPI: a new system to observe communication in plants

How do leaves, stems and roots of an adult plant communicate when facing environmental stress?

This question is addressed by MAPPI (MAcro Plant Projection Imaging), a new optical imaging system developed by a team of researchers from the University of Milan and a team of the Politecnico di Milano leaded by Andrea Bassi. The study has been published in Science Advances.

MAPPI makes it possible to observe in real time the internal communication of an entire plant as it responds to stimuli such as injury, flooding, burning or other environmental stresses. Thanks to a dual perpendicular view, the system allows the simultaneous visualisation of leaves, stems and roots, overcoming the limitations of traditional tools designed for small laboratory-grown plants.

One of MAPPI’s distinctive features is its ability to study plants of a size comparable to those grown in greenhouses, which until now have been difficult to analyse using conventional imaging techniques. The system is modular, open source and low cost, making it easily replicable in a wide range of research settings.

By exploiting fluorescence, MAPPI enables real-time monitoring of key signals involved in plant internal communication, such as changes in calcium ion concentration and glutamate accumulation, revealing a bidirectional signalling network between leaves and roots that is more complex than previously assumed.

The system is also designed to be expanded with additional sensors, allowing the simultaneous monitoring of multiple molecular signals. MAPPI therefore represents a significant advancement in the study of adult plant physiology, with important implications for the future of agriculture in the context of climate change.