Vegetative
Soil warming significantly increased early vegetative growth for some germination strategies (Table 1). Soil warming significantly increased the number of leaves and the leaf increment (leaf number per day) in the immediate and postponed-deep germination strategies, but not the staggered or postponed strategy (Fig. 2a and b). Leaf size decreased under warmer conditions only in the immediate germination strategy, while for other strategies leaf number between ambient and warmer soil was constant. SLA differed across strategies and warming increased SLA regardless of the germination strategies (Table 1).
The effect of warming and germination strategies on vegetative growth diminished at the transition from vegetative to reproductive stage when many individuals had just started to flower. Rosette size indicated by the canopy area and leaf number were not affected by warming and germination strategy (Table 1). Interestingly, at the transition to reproductive stage, warming was associated with a reduction instead of an increase in leaf increment regardless of germination strategy – contrary to the response shown during the early vegetative state (Fig. 2, Table 1). Thereby, despite the positive effect of warming on vegetative at the early stage, final aboveground biomass of plants growing under warming treatment was significantly lower than that of ambient plants (Fig. 1, Table 1).