Results
After size effects were removed, germination time, sampling time and their interaction had significant effects on most traits (Table 2). Total mass increased over time (LSD, p < 0.05) for all germination treatments (GT) except for those germinated in late spring (GT2), which had no difference in total mass between the second and third samplings (Fig. 1). Individuals that germinated in spring (GT1) experienced a long growth period (110 days) to reach 6.10 g of final total mass, whereas those germinated in late spring (GT2) and summer (GT3) grew rapidly, reaching 8.08g and 4.93g of total mass within 70 days, which was higher (p < 0.001) or did not differ from that of spring germinants. GT2 germinants had the greatest total mass of all at the second stage (p < 0.001), even greater than the final total mass of GT1 germinants (p = 0.001). The individuals germinated in late summer (GH4) had the lowest total mass (2.41 g) of all at the final harvest (p < 0.001), only reaching 29.8% of the final total mass of GT2 ones.
Across all harvests, earlier germinants (GT1 and GT2) had higher stem mass and allocation, root mass and allocation, with greater stem length, stem diameter and main root diameter, while germinants of GT2 and GT3 had higher reproductive mass and allocation, with more-parallel and larger leaves, and GT4 germinants had the higher leaf (petiole and lamina) mass and allocation, compared to other germinants (p< 0.05); meanwhile, mail root length and lateral root length were less affected by germination timing, especially at the last two stages (Fig. 2, 3). Individuals of GT2 had the highest petiole length and lamina size of all (p < 0.05), GT3 germinants had the greatest petiole angle of all (p < 0.01), and GT4 germinants had the most leaves of all (p < 0.05; Fig. 3).
For all GT treatments, as plants grew, stem mass, reproductive mass and all morphological traits except for leaf number and lateral root number tended to increase in most cases (p < 0.05), petiole mass allocation and lamina mass allocation tended to decrease (p< 0.05) and lamina mass decreased from the second to the third harvest (p < 0.001; Fig. 2, 3), and stem mass allocation decreased over time for individuals of GT3 only (p< 0.05; Fig. 2). Because of the changes in these traits over time, their responses to germination timing also varied with different stages (Fig. 2, 3). For example, differences between different GT treatments became less significant in root allocation, petiole length, main root length and lateral root length as plant grew larger. GT2 germiants had the highest reproductive mass and allocation at the second stage, but the highest ones became GT3 germinants at the third stage. GT1 germinants had more leaves than others at the first stage, while GT3 and/or GT4 had more leaves than others at the second and third stages. GT1 and GT2 germinants had higher lateral root length at the first stage, but such advantages of them disappeared over time, they instead had a greater number of lateral roots, compared to other germinants.