Researchers have developed a new sensor that monitors a plant’s health for early nitrogen deficiency diagnosis. The portable Raman leaf sensor can be clipped on plants to monitor their health. (Image credit: Nature)


Believe it or not, plants do experience stress. They’re not worrying about bills to pay or political corruption. Rather, plants get stressed due to negative effects on their environment. This can cause them to get sick and put crops at risk. Researchers at Singapore-MIT Alliance for Research and Technology (SMART) and Temasek Life Sciences Laboratory (TLL) have designed a portable optical sensor that can determine whether a plant is under stress. The device can help framers and plant scientists keep track of plant health in field conditions.


To take on growing food insecurity, many framers turn to precision agriculture, which uses new sustainable technologies to increase crop yields and profitability while decreasing traditional growing inputs, like insecticides and fertilizer. But it often needs new technologies for rapid diagnosis of plant stresses before the onset of visible symptoms. This is where SMART’s new sensor comes in. The Raman leaf-clip monitors a plant’s health and allows for early diagnosis of nitrogen deficiency in plants, which can be linked to loss of yield and early leaf deterioration.


The leaf clip is equipped with an optical sensor, a fiber-based Raman probe assembly, that probes the leaf chemistry and reports its stress state. Results showed in vivo measurements using the Raman sensor under full-light growth conditions to be consistent with measurements taken with a benchtop Raman spectrometer on leaf sections. The work was developed in the Disruptive and Sustainable Technologies for Agricultural Precision (DiSTAP) Interdisciplinary Research Group (IRG) within SMART, MIT’s research enterprise in Singapore.


“We demonstrated that early diagnosis of nitrogen deficiency — a critical nutrient, and the most important component of fertilizers — in living plants is possible with the portable sensor,” said MIT professor of electrical engineering and computer science Rajeev Ram, co-lead author of the paper and principal investigator at DiSTAP.


Though the study focused on measuring nitrogen levels in plants, the team believes the device can be used to detect other plant stresses, like those caused by heat, drought, cold, along with saline and light stress. The sensor’s wide range of plant stressors, along with its simplicity and speed, makes it a helpful tool for farmers to ensure crop health. The team also thinks their findings can help farmers increase crop yield with minimal negative effects on the environment, including reducing nitrogen runoff, which can minimize pollution of aquatic ecosystems.


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