Figure 8
Product of the rate of cell volume increase and the duration of interdivision phase measured under different illumination conditions. A: LL conditions. Light intensities are as indicated (PAR values are in m-2 s-1). B: LD conditions. Light intensities are as indicated (PAR values are in m-2 s-1). C: LDL conditions. PAR was 200 μmol m-2 s-1 in all cases. Various light exposure patterns were used, the duration of the dark periods ranged from 0.8 to 4.0 hours (filled circles), and 9.0 hours (three open triangles). If the value of T LD is adjusted by subtracting the time cells spent in the dark (T D ), the product of μ L T LL , which is equal to μL(T LDL - T D ), becomes approximately equal to 1.4 (three filled triangles) where T LL is the sum of first and second light period duration. D: L1L2 conditions. The intensities of light exposure were lowered (from 200 to 100, 200 to 20, 200 to 2, and 100 to 10 μmol m-2 s-1) at various times. For all ratios V(T L1 )/V(0) < 2, the product of μ L1 T L1L2 increased far beyond 1.5 (two filled triangles). If we substitute μ L1 T L1L2 with μ L T L1 + μ L2 T L2 , the value becomes near to 1.5 (two open triangles) where μ L2 is the rate of the volume increase during the second light period and T L2 is the duration of the second light period.