Discussion
Plants of Abutilon theophrasti can germinate over a wide range of period in growth seasons. Germination timing can influence the strength and direction of selection on plant performance and response in growth and reproductive traits later in the life cycle (Donohue et al., 2005; Mercer et al., 2011; Weinig, 2000). Germinating earlier generally results in higher fecundity, but selection on survival may favour early, intermediate, or late germination (Donohue et al., 2010; Kalisz, 1986; Verdu´ & Traveset, 2005), and thereby selection on germination timing may be conflicting (Akiyama & Ågren, 2014). It suggested there is an optimal germination time for plants (Gremer et al., 2020; ten Brink et al., 2020). This was supported by our results that the optimal germination time for A. theophrasti was late spring, earlier or later germination had adverse effects on plant performance to different extents. In spite of this, individuals with advanced or delayed germination can still adopt different strategies in coping with subsequent environmental conditions via plasticity in biomass allocation and morphological traits.