Updated project metadata. Plants adapt to the prevailing photoperiod by optimally adjusting growth and flowering to the availability of energy. When Arabidopsis thaliana plants are grown in long days individual leaf growth is favoured, whereas whole plant leaf area is decreased because of the rapid shift to floral stages and, consequently, the low number of total leaves. To understand the molecular profiles of adaptation to long-day conditions we profiled Arabidopsis leaf number six of plants grown in 16 hours of light at four developmental stages both at the end of the day and the end of the night and compared the profiles to those acquired in short day conditions.