The bottles were illuminated from two sides by a total of four 40-W fullspectrum fluorescent bulbs Duro-test Vitalite Lighting, Inc.,
Philadelphia operated on a 16 h:8 h light:dark cycle. When on,
the bulbs provided an average illuminance that totaled 4,300 lx at
the two faces of each bottle Lutron LX-101 m, which is equivalent to about 12 W/m2
of photosynthetically active radiationLiCor 2008.