. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 7-RAY EFFECTS ON TUBULARIA 195 Exposures ranged from 10,000 R to 350,000 R requiring to minutes of irradiation. The temperature during irradiation ranged from 10° C to 23° C. This was dependent upon the time required to accumulate a particular radiation exposure. •For exposures greater than 75,000 R, iced sea water varying from 10° C to 18° C was used and changed during the irradiation procedure. Earlier observations showed that a temperature rise above 23° C during irradiation killed the organism. Stems were observ
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 7-RAY EFFECTS ON TUBULARIA 195 Exposures ranged from 10,000 R to 350,000 R requiring to minutes of irradiation. The temperature during irradiation ranged from 10° C to 23° C. This was dependent upon the time required to accumulate a particular radiation exposure. •For exposures greater than 75,000 R, iced sea water varying from 10° C to 18° C was used and changed during the irradiation procedure. Earlier observations showed that a temperature rise above 23° C during irradiation killed the organism. Stems were observed under a dissecting microscope at different time periods post-irradiation. Seven stages of regeneration were defined. These were: pink, striated, double striated, pinched, bundle, emerging and emerged (Fig. 1). At SEVEN REGENERATION STAGES. PINK STRIATED DOUBLE PINCHED BUNDLE EMERGING EMERGED STRIATED FIGURE 1. A diagrammatic representation of seven recognizable stages in Tubularia regeneration. each observation time a count was made of stems in each category. Stems under- going no regeneration were also counted. Unirradiated stems fully regenerated complete hydranths within 36 to 48 hours after cutting. All stems died when kept more than five days in this particular laboratory situation. RESULTS Time of irradiation Pilot experiments were performed to establish an optimum irradiation pro- cedure. Preliminary experiments showed that stems of Tubularia will undergo complete regeneration at a radiation exposure of 10,000 R, but at a slower rate when compared with unirradiated stems. Experiments were performed to determine the most effective time to irradiate the organism. Groups of 10 stems were cut within the same time interval and exposed to 10,000 R at 2, 6, 12 and 18 hours after cutting. Comparisons were made of the number of stems from each group in the emerged stage of regeneration at these times. No stems, controls or irradiated, had reached the emerged stage 24 ho
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
