A portable optical sensor that can monitor whether a plant is under stress has been developed by a group of Singapore-based researchers. 

The device offers farmers and plant scientists a new tool for early diagnosis and real-time monitoring of plant health in field conditions.

It can detect levels of plant stress phenotypes such as drought, heat and cold stress, saline stress, and light stress. The wide range of plant stressors that can be detected by these leaf-clip probes and transmit data rapidly to farmers and scientists. 

Known as the Raman sensor clip, the design came from researchers from the Disruptive & Sustainable Technologies for Agricultural Precision (DiSTAP) that’s part of the Interdisciplinary Research Group (IRG) of the Singapore-MIT Alliance for Research and Technology (SMART), along with Temasek Life Sciences Laboratory (TLL). 

The portable Raman system was designed in collaboration with local company Technospex Pte Ltd. The leaf-clip Raman sensor is made of a 3D printed clip that is built around a fiber-based Raman probe assembly.

Raman is known as a light scattering technique where a molecule scatters incident light from a high intensity laser light source. This technique will then be translated to plants. 

In a paper titled “Portable Raman leaf-clip sensor for rapid detection of plant stress” published in the prestigious journal Scientific Reports, SMART DiSTAP and TLL scientists elaborated on the design and build of the leaf clip which was then tested to see how it allows the optical sensor to probe the leaf chemistry and establish the stress state.

The team believes their findings and design on the clip can help farmers maximise crop yield, while preserving the environment, and mitigating harmful effects on aquatic ecosystems by reducing nitrogen runoff and infiltration into the water.

“Extension of this work to a wider variety of crops may contribute globally to improved crop yields, greater climate resiliency, and mitigation of environmental pollution through reduced fertilizer use,” said co-lead principal investigator at DiSTAP, deputy chairman at TLL and co-lead author of the study, Nam-Hai Chua. 

The research was carried out by SMART and supported by the National Research Foundation (NRF) Singapore under its Campus for Research Excellence And Technological Enterprise (CREATE) programme.