Responses of Arabidopsis leaves to prolonged osmotic stress are mediated by their developmental stage

Drought is an important environmental factor affecting plant growth and biomass production. Despite this importance, little is known on the molecular mechanisms regulating plant growth under water limiting conditions. The main goal of this work was to investigate, using a combination of growth and molecular profiling techniques, how Arabidopsis thaliana leaves adapt their growth to prolonged mild osmotic stress. Fully proliferating, expanding and mature leaves were harvested from plants grown on plates without (control) or with 25mM mannitol (osmotic stress) and compared to seedlings at stage 1.03. Total RNAs were extracted using Trizol method from vegetative part of seedlings at stage 1.03 and leaves that are fully proliferating, expanding or mature. All plants were grown in vitro on medium without (0mM) or with mannitol (25mM) in three independent biological experiments. Each sample was pooled from multiple plants and multiple plates in one experiment. RNA samples were submitted to ATH1 array hybridization.