Choy sum and spinach are widely consumed leafy greens in Asia, but they are sensitive to environmental stresses that can affect crop quality and yield.
This issue can be managed by a novel near-infrared (NIR) fluorescent nanosensor, which can monitor how plants grow without invasive or damaging procedures, helping to optimise both yield and quality for cities aiming to enhance food security amid space constraints.
The science
Researchers at Singapore-MIT Alliance for Research and Technology (SMART), MIT’s research enterprise in Singapore, used commonly consumed Asian vegetables as test crops to trial their new nanosensor.
“We selected choy sum and spinach as test crops because they are widely consumed leafy greens in Asia, particularly in Singapore, and are sensitive to environmental stresses like shade, heat and drought. This made them ideal for studying plant growth hormone dynamics,” said Dr Khong Duc Thinh, research scientist at SMART’s Disruptive & Sustainable Technologies for Agricultural Precision (DiSTAP) interdisciplinary research group (IRG).
The project is a collaboration between SMART, Massachusetts Institute of Technology (MIT), and Temasek Life Sciences Laboratory (TLL).
According to DiSTAP researchers, this is the world’s first near-infrared (NIR) fluorescent nanosensor that can detect indole-3-acetic acid (IAA) — a key plant growth hormone known as auxin, which controls how plants develop, grow, and respond to stress.
This can be done in real time across multiple plant species, and without damaging the plant.
Positive results
The nanosensor successfully detected elevated auxin levels in crops like choy sum and spinach when they were exposed to shade.
This indicates that the nanosensor can reliably pick up real-time hormonal changes associated with environmental stressors like low light.
“Our nanosensor’s success in detecting elevated auxin during shade avoidance in these crops demonstrates its robustness for scaling up application to other common leafy vegetables like kai lan, bok choy, lettuce, and other high-valued crops,” said Dr Khong. “Enabling early stress detection in common and high-valued leafy greens helps optimise growth conditions in space-limited urban farms, boosting yield.
He added that its non-invasive, species-agnostic design makes it adaptable for urban farms across Asia, where land constraints and food security are pressing issues.
Upcoming plans
DiSTAP is collaborating with urban farming partners in Singapore to explore pilot trials of the nanosensor on high-valued leafy greens such as kale and arugula.
Discussions with potential commercial partners are also ongoing.
These efforts focus on integrating the sensor into real-world farming settings to enhance crop yield through early stress detection.
The nanosensor’s growth hormone data can be integrated into farm management systems via advanced analytic platforms, feeding real-time hormone levels into existing digital tools that monitor environmental factors like light, humidity and irrigation.
“We envision our system would allow food producers to correlate plant hormone fluctuations with growth conditions by using Application Programming Interfaces (APIs) to synchronise data with platforms used in urban farms, enabling precise adjustments to irrigation or lighting for crops,” said Dr Khong.
The researchers are developing an artificial intelligence (AI) and machine learning (ML) platform to streamline and integrate data from the NIR nanosensor and Raman spectroscopy – a technique that uses light to analyse the chemical makeup of plant tissues without damaging them.
They will then translate the data into actionable recommendations.
“Farmers will then be able to adjust water or light conditions accordingly, even without scientific training,” said Dr Khong.
“We also endeavour to build and test the platform in Singapore’s urban farm pilot sites and validate its recommendations in collaboration with farmers to ensure real-world relevance and usability.”
