Germination and seedling growth characteristics of heterotypic seeds from Polygonum aviculare

Polygonum aviculare, an annual herbaceous plant of Polygonaceae, is a potential lawn greening resource. P. aviculare produces two types of seeds: smaller black seeds in summer and larger brown seeds in autumn. To explore whether there were differences in the size and biomass allocation patterns of seedlings from heteromorphic seeds, we studied the germination and seedling growth characteristics of the two kinds of seeds by field pot culture and laboratory experiments. The results showed: (1) the germination percentage of fresh harvested brown seeds was significantly greater than that of black seeds (P < 0.05); (2) seedlings arising from brown seeds had a significantly greater height than those from black seeds (P < 0.05), while seedlings arising from brown seeds had more rapid root elongation and biomass accumulation, and larger cotyledons than seedlings from black seeds; and (3) at the last measurement at the four-leaf stage on May 12, the root/shoot ratios of seedlings from brown and black seeds were 0.07 and 0.29, respectively, and the root/shoot ratios of seedlings arising from black seeds were significantly greater than those from brown seeds (P < 0.05). The differences between seedlings of heteromorphic seeds provide flexible ecological adaptation strategies, which ensures the successful reproduction of the population to the maximum extent.