The light intensity regimes included 134, 32, 8, 0.87, 0.09,
0.01 lmol m-2 s-1 and dark, with 22 C constant temperature.
Seeds were handled under a dim green safety light for dark treatment, and black boxes were used to provide completely dark environments.
For the other light treatment, seeds were placed under a photosynthetic photon fluxed intensity of 134 l mol m-2 s-1 (measured at the top of the Petri dish) and inspected daily.
The light intensity (measured using a light sensor at the bottom of different layers of paper) was adjusted by wrapping the outside of plastic petri-dish with layers of thin white papers.