https://www.nature.com/articles/s41598-025-17929-8

A team from the University of Tsukuba and the RIKEN Center for Sustainable Resource Science has found that spraying ethanol during tomato cultivation confers heat stress tolerance and improves sugar content and vitamin C content.

The cultivation environment consisted of harsh heat stress conditions in a summer greenhouse. Ethanol was sprayed regularly once a week during cultivation of the tomato phyA mutant. As a comparison, the plant growth regulator 4-CPA (4-chlorophenoxy acetic acid, a synthetic auxin), which is effective for heat stress tolerance, was also used.

Tomatoes sprayed with ethanol or 4-CPA showed increased plant height and stem thickness compared with untreated tomatoes and maintained overall healthy growth. Furthermore, sugar content (Brix) and vitamin C contents increased. Ethanol spraying had enhanced the expression of genes encoding heat shock proteins and antioxidant enzyme genes. The expression of genes involved in auxin and gibberellin synthesis was also promoted.