Fig. 8.

Determination of free proline content and analysis of AtproDH1 and AtproDH2 expression in Arabidopsis. Free proline content at different stages treatment for (A) basal thermotolerance (BT) and (B) acquired thermotolerance after short-time recovery (ATSR) using 5-d-old seedlings. H, heat stress; R, recovery. Data are means (±SD) of three independent experiments. Significant differences compared with 22 °C were determined using Student’s t-test (*P<0.05). (C–F) Fold-changes in the expression levels of AtproDH1 and AtproDH2 were detected at different stages of the BT treatment (C, D) and the ATSR treatment (E, F) using qPCR with 5-d-old seedlings. Data are means (±SD) of three biological replicates. Significant differences between the wild-type and transgenic plants were determined using Student’s t-test (*P<0.05, **P<0.01).