We are interested in molecular mechanisms underlying plant’s responses to environment and developmental processes regulated by them. Plants have evolved plastic developmental programs with both genetic and epigenetic basis to adapt their sessile mode of life to changing environment. Using an angiosperm, Arabidopsis thaliana and a liverwort, Marchantia polymorpha as model systems, we have been investigating growth phase transition in response to environmental signals such as day length, sexual reproduction processes from germline specification to gametogenesis, and evolution of regulatory systems. By studying two representative model species from phylogenetically distant clades, we aim to elucidate general principles of environmental response and development in land plants.