3.2 Plasmotype effects on the plasticity of life history vs circadian clock and ChlF traits in RHL
We also included a photosynthetic rhythmicity analysis to the RHL, similar to the one we previously conducted for the ASHER population, i.e., under optimal (OT) and high temperatures (HT) environments using SensyPAM platform (See Methods; (Bdolach et al. 2019)). We found that the amplitude was significantly higher under HT (0.03 ±0.01) compared to OT (0.015 ±0.006) (Figure 2a ), whereas for the period, significantly higher values under OT (24.9 ±2.6 h) compared to HT (23.3 ±1.9 h; Fig. 2b ) were observed. This clock plasticity is similar to the one described for the ASHER (Bdolach et al. , 2019) with acceleration of the rhythmicity under HT. Fv/Fm is significantly higher under HT (0.93 ±0.01) in comparison to OT (0.92 ±0.01; Figure 2c ) and significantly different for Fv/Fmlss (0.9 ±0.01 in OT vs. 0.91 ±0.01 in HT; Fig. 2d ). Mean values of NPQlss and Rfd per se (averaged over the time period of the measurement) were significantly different under OT in comparison to HT (NPQlss 0.66 ±0.1 vs. 0.43 ±0.08 and Rfd 1.6 ±0.2 vs. 1.18 ±0.18; Figure2e, f ). Overall, these results suggest that under HT, photosynthesis is more efficient than under OT.
For the clock traits in the RHL, we also found significant differences between the contributions of plasmotype and nucleotype to the variation of photosynthetic rhythm parameters (Table 1 ), but to a lesser extent than for fitness traits. Difference in contribution was higher when analyzing fitness traits, where the plasmotype’s PVE (34%) clearly topped the nucleotype’s PVE (22%), for period under HT. Similarly, variation in the thermal plasticity of photosynthetic rhythm’s amplitude value (measured as “delta amplitude”) between hybrids is better explained by plasmotype (32%) compared to nucleotype (24%) (Table1 ).