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 ).