ABSTRACT
Four ecotypes of A. thaliana (L.) (Ct-1, Pf-0, Old-1 and Per-1) from low to high latitudes were grown under different light (300 mmol photon m-2s-1 and 150 mmol photon m-2s-1) and temperature (22 and 14 ºC) conditions to investigate their effects on phenotypic plasticity and ecotypic variations in plant growth and first flowering time. The results suggest that in A. thaliana low temperature decreases both phenotypic plasticity and ecotypic variations in first flowering time and total dry matter at final harvest under different light intensities. Relative growth rate is the most stable parameter of A. thaliana that is hardly affected by ecotype (no effect), light (no effect) or temperature (small effect) and this may one of the reason why A. thaliana is widely distributed on earth as a result of adaptations to different environments.