Fig. 1: Barley shows HS memory.

a Treatment scheme for HS assays. HS treatments were performed on 7-day-old Golden Promise plants by exposing them to 44 °C for 3 h. Plants were primed 1 h before HS by exposure to 38 °C for 2 h to test acquired thermotolerance (aTT) or 2 or 3 d before HS by exposure to an ACC treatment (38 °C for 2 h, 23 °C for 1 h and 44 °C for 1 h) to test HS memory (maTT). After HS, plants were transferred to soil and phenotyped 21 d later. b, c Dry weight (b) and survival (c) analysis show that priming induces tolerance to normally lethal HS. Boxplots (b) show median and quartile ranges with whiskers extending to 1.5 of the interquartile range of the data. Numbers below the box plots indicate the number of analyzed plants over 3 independent replicates. Data in c are mean ± SD from 3 independent experiments. Different letters indicate statistically significant differences (p < 0.05, Welch two-sided t-test (b), Fisher's exact test (c)). Source data are provided as a Source Data file.