Fig. 2

Plant positions in the labeling chamber. a The positions of 15 plants (P1–P15) and the light intensity (in µmol photon m⁻² s⁻¹) distribution measured in and around each plant position without the glass cover of the labeling chamber. The light intensity thus measured was ranging between 204 (P15) and 279 (P7) µmol photon m⁻² s⁻¹ among the 15 positions, with the mean intensity of 238 µmol photon m⁻² s⁻¹. b A picture of the closed labeling chamber with 15 Arabidopsis plants placed under LED lamps in a controlled climate chamber. The bottom of the plant cups (see Additional file 1: Fig. S1 for description of the plant cup) was touching the water in a shallow basin attached to the lower surface of the chamber body. The basin can be filled and drained through watering tubes (seen in the front) without opening the chamber