Ultrasound device measures the impact of drought on plants

A new device developed by a team of Lithuanian and Spanish researchers allows detection of the alteration produced by drought on certain key parameters of the plant’s physiological state

by Matteo Cavallito

 

Drought generates biochemical and physiological changes in plants, reducing nutrient levels and damaging the ecosystem. These phenomena, experts say, also have repercussions on human health and the vulnerability of livelihoods, but their impact is often difficult to assess. Existing methods, in fact, can be detrimental to the plant and in many cases take a long time before returning results. Researchers at Kaunas University of Technology (KTU) in Lithuania, however, now believe they have found a solution.

Not just for vineyards

This is reported by Linas Svilainis, professor and co-author of a new device that, he explains in a note released by the Lithuanian university, promises to solve the problems of impact and duration associated with traditional plant status monitoring systems. Developed in collaboration with the Spanish National Research Council (CSIC) and the Agro-Food Research and Technology Centre of Aragon (CITA), the instrument uses non-contact ultrasound on an uncut leaf to assess its characteristics.

The initial idea was to develop a control system for vine plants which, the researchers explain, are particularly vulnerable to drought due to their shallow roots that limit their ability to extract water from the soil.

Lack of water supply, moreover, can affect the sugar and acidity levels of the grapes, negatively impacting the quality and taste of the wine. In the course of time, the researchers found that the device they created was also adaptable to other plants. “The device developed by our team can extract mechanical properties from ultrasound measurements, allowing plant scientists to analyze the physiological state of plants,” explains Svilainis.

The role of ultrasound

The instrument, in particular, measures aspects such as resonance frequency, thickness, density and attenuation of the plant. According to the authors, these measurements are correlated with key parameters of the plant’s physiological state. Including potential and water content, which obviously highlight drought stress.

In addition, it is possible to record in real time key elements such as instantaneous temperature changes that typically escape traditional thermometers (the latter being too slow to detect them).

“Instead of, for example, threading a pressure sensor into a plant trunk, we use a non-invasive, non-contact technology,” explains Svilainis. “In addition, it is light, convenient, and results are obtained immediately. Using other devices, the leaves have to be cut and taken to the laboratory, which takes time, but here we can get the results right in the field”.

A new drought monitoring device

The device, the note explains, has been granted a Lithuanian patent and its authors have applied for the same at the relevant European Office. Designed for large leaves (more than 3 cm in diameter), the device can be further developed in the future to extend its application to other plants. In this way it will contribute to the monitoring of a phenomenon that is becoming increasingly common across the continent.

Since 2018, the European Environment Agency (EEA) explained last year, more than 50 per cent of European soil has been affected by extreme drought conditions.

“Long-term climate projections indicate that southern and central Europe will become even drier and hotter throughout the 21st century with devastating consequences for the agriculture sector,” the EEA wrote on the occasion. “Total economic losses across all economic sectors linked to droughts are expected to rise by the end of this century from the current EUR9 billion per year to EUR 25 billion per year at 1.5 degree Celcius (°C) of global warming, EUR 31 billion per year at 2°C of warming and EUR 45 billion a 3°C warming based on scientific scenarios.”