Experiments were carried out using tomato (Solanum lycopersicum cv. Taiankichijitsu, Nanto Seed Co. Ltd., Nara, Japan) cultivated in a sunlight-type plant factory. Individual plants are usually cultivated for a year; in this experiment, tomato seedlings were grown by Berg Earth Co. Ltd. (Ehime, Japan) and transplanted into rockwool cubes. We sampled the fifth leaves every 2 h for 2 days, starting at 14:00 on 2 June 2015 and ending at 10:00 on 4 June 2015. We sliced leaf segments and stored them at 0 degree with RNA-later solution (Qiagen, Valencia, CA, USA), an aqueous nontoxic tissue storage reagent that rapidly permeates tissue to stabilize and protect the integrity of RNA.