Researchers at the University of Illinois at Urbana-Champaign have reported that it is possible to detect and predict heat damage in crops using the fluorescent light signature of their leaves under heat stress. This could support crop monitoring under the heat stress of climate change.
Higher temperatures affect the growth of plants and especially field crops, with temperatures above certain thresholds causing serious damage, including stunted growth, burning, failure to flower and failure to produce seeds.
This is a serious concern in agriculture as climate change causes extreme weather events, including annual heat waves.
The findings of this study suggest that this damage can be monitored at scale using the fluorescent light signature of crops.
The study measures sun-induced chlorophyll fluorescence (SIF) to track a plant’s photosynthetic health.
This type of fluorescence occurs when plants absorb sunlight (in the range of 400-700 nm) and radiate some of the photosynthetic energy in the near infrared range (in the range of 650-850) through the leaves.
“There is a link between sun-induced chlorophyll fluorescence and photosynthesis rate in plants; however, it was unclear whether SIF detection could measure physiological responses in heat-stressed plants, ”said lead author Hyungsuk Kimm, a graduate student.
“For example, when soybeans are exposed to high temperature stress, they show no marked changes in canopy structure, and conventional remote sensing signals do not provide clear consistent spectral signatures.
” The researchers examined the relationship between SIF and crop yield using a hyperspectral detection system to measure SIF over soybean crops in Illinois.
They used infrared lamps to gradually raise the temperature – up to six degrees above the ambient droplet temperature – while monitoring changes in chlorophyll fluorescence.
This experiment, the first of its kind, has shown a link between heat stress, SIF and grain quality, and clarifies how heat stress affects crop yield.
“We found that sun-induced fluorescence responds to increases in temperature and corresponds to fewer leaves of lower quality soybeans,” said study leader Professor Kaiyu Guan.
“We also found that heat stress greatly affects soybeans during their reproductive stages when the plants produce grain, ultimately affecting the size and amount of the resulting soybeans.” Professor Lisa Ainsworth, an expert in plant biology, added:
“The technique could help breeders identify more heat-resistant crops and help farmers select the best crops to grow in the US Corn Belt as the temperature rises, as predicted by much climate change. models. “