Fig. 1

The timing of procedures leading up to the measurement of rates of meiotic recombination (MR, in seeds) or somatic mutations (SMs, in seedlings) in this study. One of the parents of the analysed seeds/seedlings was stressed by shifting wild type plants (Columbia/C24) grown at 22 °C to either 12 °C or 32 °C for one hour at either 36 (or 41) days after sowing (DAS). 36 h later, at 38 (or 43) DAS, we selected some of the flowers that were at Floral Stage 12, and emasculated them. This meant that these flowers were at Stage 11 when the stress was applied (and thus undergoing male and female gametophyte development). 48 h after emasculation, at 40 (or 45) DAS, when the emasculated flowers were now at Stage 14 we (i) pollinated the emasculated flowers with pollen collected from non-emasculated Stage 14 flowers that were on unstressed detector line plants that had been raised, for 40 (or 45) DAS at 22 °C; or (ii) collected pollen from the non-emasculated flowers of Stage 14, stressed, wild type flowers, and used this to pollinate Stage 14 flowers that were on unstressed, detector line plants that had been raised, for 40 (or 45) DAS at 22 °C. In all cases, seeds were collected 16 (for SMs) or 20 (for MR) days after pollination, and either used for analysing rates of MR directly, or planted and grown for a further 21 d, after which the seedlings were analysed for rates of SMs. Coloured threads were used to identify plants of different ages, plants grown at different temperatures, and to differentiate between emasculated, non-emasculated and crossed flowers. The timing of stages is based on data presented in the literature [52, 55, 59]