Impacts of growth form and phylogenetic relatedness on seed germination: a large-scale analysis of a subtropical regional flora

Plant regeneration strategy plays a critical role in species survival and can be used as a proxy for the evolutionary response of species to climate change. However, information on the effects of key plant traits and phylogenetic relatedness on seed germination is limited at large regional scales that vary in climate. To test the hypotheses that phylogenetic niche conservatism plays a critical force in shaping seed ecophysiological traits across species, and also drives their response to climatic fluctuation, we conducted a controlled experiment on seed germination and determined the percentage and rate of germination for 249 species in subtropical China under two temperature regimes (i.e., daily 25ºC; daily alternating 25/15ºC for each 12 h). Germination was low with a skewed distribution (mean = 38.9% at 25ºC, and 43.3% at 25/15ºC). One fifth of the species had low (<10%) and slow (4–30d) germination, and only a few (8%) species had a high (>80%) and rapid (1.2–6.6d) germination...