Difference in ultraweak photon emissions between sulfonylurea-resistant and sulfonylurea-susceptible biotypes of Scirpus juncoides following the application of a sulfonylurea herbicide

We examined the ultraweak photon emissions from a paddy weed, Scirpus juncoides, to assess the availability of photon emissions for the identification of weed biotypes resistant to sulfonylurea herbicides. The emission intensity from the plant organs increased when treated with a sulfonylurea herbicide in a concentration‐dependent manner. The increment in emissions was higher in the sulfonylurea‐resistant biotypes than in the sulfonylurea‐susceptible biotypes. The difference between the biotypes was greater in the culms than in the roots and remained so through the vegetative growth stage to the flowering stage. This difference was independent of the seed source or mutations in the acetolactate synthase genes of the resistant biotypes. These results suggest that the determination of ultraweak photon emissions can be a useful method for identifying the sulfonylurea‐resistant biotypes of S. juncoides.