Figure 1.

Illustration of sampling strategy during seed set of study species. Different color of square cells represents different populations/ecotypes for P. glauca and Arabidopsis, where a white square cell with a cross inside represents a corresponding population/ecotype that has not yet been fertilized or has already matured, thus no sampling possibilities in those stages (e.g., only three sampling timepoints for Pop1 of P. glauca). Populations of P. glauca are exposed to similar phenology during seed set in the seed orchard roughly within weeks of July through August, and ecotypes of Arabidopsis are cultivated in three growth chambers with the same growth conditions in periodic cycles to reap three biological replicates. A dashed line in the horizontal direction roughly divides seed development into two phases: morphogenesis (up) and maturation (down). Tick symbols (√) mark the sampling timepoints. An asterisk (^*) means that after the “mature” phase in Arabidopsis, another 5–8 days are needed to complete post-maturation and seed dormancy arrest. Plant images reprinted with permission of source: Google image.