. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. RHYTHM OF LUMINESCENCE 447 LJ O Z LiJ O (f) LL) 380 FOOT CANDLES FOOT CANDLES 120 FOOT CANDLES 200 FOOT CANDLES 45 FOOT CANDLES DARK CONTROL. 0 50 60 70 TIME -HOURS FIGURE 6. This illustrates phase shifting in a rhythmic culture by a single 2%-hour exposure to light, and the effect of intensity upon the magnitude of the phase shift. Prior to the time shown on the graph, all cultures were in LD conditions, and "two hours" on the time axis was the end of the last 12-hour light period. All cultures were put in the dar
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. RHYTHM OF LUMINESCENCE 447 LJ O Z LiJ O (f) LL) 380 FOOT CANDLES FOOT CANDLES 120 FOOT CANDLES 200 FOOT CANDLES 45 FOOT CANDLES DARK CONTROL. 0 50 60 70 TIME -HOURS FIGURE 6. This illustrates phase shifting in a rhythmic culture by a single 2%-hour exposure to light, and the effect of intensity upon the magnitude of the phase shift. Prior to the time shown on the graph, all cultures were in LD conditions, and "two hours" on the time axis was the end of the last 12-hour light period. All cultures were put in the dark at that time and the control was left in the dark thereafter. The remaining cells were exposed to a 2%-hour illumination beginning 6 hours after the light-to-dark transition (indicated by the rectangle on the time axis). Following this 2%-hour illumination they were returned to darkness for the remaining time. The intensities used are shown in the figure. A 21/L>-hour exposure to 1400 foot-candles (not plotted) was found to be no more effective than the ex- posure to 660 foot-candles (Fig. 7). Temperature during experiment, 21° C. The effect of varying the light intensity was determined in experiments such as the one shown in Figure 6. The amount of phase shift was found to increase with increasing light intensities, up to a "saturation" value of about 800 foot- candles. This relationship is illustrated in Figure 7, and the stability of the re- setting is shown by plotting on the same graph the phase shift measured at each of the subsequent cycles. Several experiments of this sort have been carried out and the same type of relationship has been observed. The quantitative values ob- tained in separate experiments were somewhat different, however, and the reason for this variation has not been Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
