GENOME SIZE, SEED SIZE AND GERMINATION TEMPERATURE IN HERBACEOUS ANGIOSPERMS

In a sample of 131 herbaceous flowering plants, nuclear DNA content is positively correlated with seed size and negatively correlated with minimum germination temperature. This tendency for large seeds to have high DNA contents and to germinate at low temperatures is at least partly because germination and growth at low temperatures (less-than-or-equal-to 5-degrees-C) take place largely by cell expansion. High nuclear DNA contents and large seed size co-occur in species in which both growth and germination take place at low temperatures. Large seed size but much lower DNA contents are found in species which germinate at low temperatures but grow at higher ones.