GENOME SIZE PREDICTS FROST-RESISTANCE IN BRITISH HERBACEOUS PLANTS - IMPLICATIONS FOR RATES OF VEGETATION RESPONSE TO GLOBAL WARMING

1. Simulated late frost was applied to five herbaceous plant communiti es in Derbyshire, UK. The results establish a clear positive relations hip between the frost resistance of the above-ground biomass and indep endently published estimates of genome size. 2. Previous studies have established that in small genome species the dependence of growth upon current cell divisions dictates that development is delayed until war mer summer conditions. As a result of this, we suggest that selection pressures promoting frost tolerance will have been less pronounced in these species and that in temperate climates their potential responsiv eness to global warming could be curtailed by the continued occurrence of late-frost events.