An explanatory model of temperature influence on flowering through whole-plant accumulation of in .

We assessed mechanistic temperature influence on flowering by incorporating temperature-responsive flowering mechanisms across developmental age into an existing model. Temperature influences the leaf production rate as well as expression of (), a photoperiodic flowering regulator that is expressed in leaves. The Framework Model incorporated temperature influence on leaf growth but ignored the consequences of leaf growth on and direct temperature influence of expression. We measured production in differently aged leaves and modified the model, adding mechanistic temperature influence on transcription, and causing whole-plant to accumulate with leaf growth. Our simulations suggest that in long days, the developmental stage (leaf number) at which the reproductive transition occurs is influenced by day length and temperature through , while temperature influences the rate of leaf production and the time (in days) the transition occurs. Further, we demonstrate that is mainly produced in the first 10 leaves in the Columbia (Col-0) accession, and that accumulation alone cannot explain flowering in conditions in which flowering is delayed. Our simulations supported our hypotheses that: (i) temperature regulation of , accumulated with leaf growth, is a component of thermal time, and (ii) incorporating mechanistic temperature regulation of can improve model predictions when temperatures change over time.