The light intensity, as measured Nvith a foot-candle meter (Weston illumination meter Model 756, Daystrom Incorporated), was approximately 1300 ft-c at the plant level during the main light period.

A statistical analysis of the slopes of the regression lines show that the slope of the regression lines in constant dark compared to constant dark + sucrose and of 2 different runs in constant light of 1300 ft-c are not significantly different.