Fig. 1: A time-series setup for stress kinetics in three 600-million-year-divergent streptophytes.

a Cladogram of Streptophyta; Phragmoplastophyta studied herein are highlighted in bold. b Summary of the stress experiment time grids and the respective investigations including RNAseq, metabolite profiling, photophysiology, and morphology. Me-specific metabolite profiling is indicated by black dots. For high light stress experiments, morphology was investigated at maximum stress (yellow dot) and maximum recovery. c Boxplots of relative quantum yield of PSII (Fq’/Fm’) during stress exposure and control, categorized by time scale from three independent biological replicates. d Boxplots of aggregated relative quantum yield of PSII (Fq’/Fm’) due to stress exposure and in control; data are aggregated based on the three biological replicates shown in c. e Scatterplots with Loess fit of relative quantum yield of PSII (Fq’/Fm’) during stress exposure and control in the first six hours of the experiment, absolute time scale. f Morphological observations before and after stress exposure with time points corresponding to b; arrowheads and zoom-ins mark notable observations that also went into the quantification. g Quantification of observed morphological effects; statistics was performed using a Kruskal–Wallis followed by a two-sided Dunn’s test for multiple comparisons. LDs, accumulated lipid droplets/small droplets; red/brown, overall color change of cell to a more red-brown shade; DPN, droplets accumulated around the nucleus. In all boxplots, horizontal lines within the boxes represent the median (Q₂); the box depicts the interquartile range (IQR) from the 25^th (Q₁) to the 75^th percentile (Q₃) while the whiskers extend to minimum or maximum values in the data determined by Q₁ – 1.5 × IQR to Q₃ + 1.5 × IQR (data points outside are defined as outliers). In d, a gray half-eye density plot next to the boxes visualizes the data distribution. Quantifications of morphological changes were done on three independent biological replicates per species and treatment; for each replicate, six to ten images where captured, wherein four to eight cells were evaluated. The P values of significant changes were: Me deformed chloroplasts, 0.00578 and 0.00279 in heat and high light versus 24 h; Me LDs, 0.00735 and 0.01280 in cold and high light versus t0; Zc deformed chloroplasts, 0.01466 for heat and HL versus 24 h; Zc LDs, 0.02386 for cold versus 24 h; Zc plasmolysis, 0.00422 and 0.02209 for heat and HL ersus 24 h; Zc red/brown, 0.00354 and 0.01166 for heat and HL versus 24 h; Zc DPN, 0.00884 for all stressors versus revovery. All P values can be found in the source data.