Annual transcriptome dynamics of Japanese cedar (Cryptomeria japonica) and effects of photoperiod and temperature on dormancy induction

To investigate the mechanism of annual rhythms in Japanese cedar, annual time series samples were collected from the cuttings planted in natural condition. Also, to investigate the effects of photoperiod and temperature during transition to dormancy, the samples of cuttings grown in the controlled-environmental chamber were analyzed by a microarray. Annual time series samples were collected at 8:00 at 12 intervals covering a year (Jun 24, Aug 5, Sep 30, Oct 30, Nov 26, Dec 24, 2013, Jan 30, Feb 21, Mar 11, Apr 9, May 9, Jun 18, 2014) from cuttings of a Japanese cedar clone (Goudai-1) planted in 1999 at the Forest Tree Breeding Center, Forestry and Forest Products Research Institute (Hitachi, Ibaraki, Japan) (Season; 24 samples). To investigate the effects of photoperiod, the potted cuttings were transferred to short day (SD; 8 hours of light and 16 hours of dark at 25 °C) and long day conditions (LD; 16 hours of light and 8 hours of dark at 25 °C), and the samples was collected from two cuttings at 0, 7, 21, 35, 49 and 70 days after transfer (experiment 1; 22 samples). Also, to investigate the effect of temperature, the cuttings were transferred to high (25 °C) and low (15 °C) temperature in long day conditions, and the samples were collected from two cuttings at 0, 7, 21, 42, 63 and 90 days after transfer (experiment 2; 22 samples).