In a recent paper (1) the author has shown that seeds subjected to various doses of x-rays show peculiarities at certain stages of the growth which are not necessarily maintained throughout the period of growth, and cannot be used as a criterion for the determination of the best dosage for yield at maturity.In order to obtain some information concerning the effects of x-rays on seeds, by examination of mature plants from x-ray treated seeds, experiments were made, on seeds of radishes, lettuce, and beans. The x-ray tube was operated at about 100,000 volts and 5 milliamperes. The rays were filtered through 1 mm. of aluminum, and the seeds were placed at a distance of 30 cm. from the target. They were subjected to the radiation for various lengths of time. The growth of the seeds was recorded every week, and showed phenomena similar to those exhibited by corn in the paper mentioned above and in agreement with the work of JOHNSON (2) and will not be discussed here.According to SHULL and MITCHELL (3) the effects due to the x-rays are more pronounced when the seeds are subjected to the radiation in sprouted condition. In order to test this hypothesis two sets of experiments were conducted; one set of seeds was exposed to x-rays when dry, while the other set was exposed when the seeds were sprouted. For the latter set the seeds were allowed to remain in trays on sterilized cotton padding saturated with distilled water until definite sprouts appeared and then subjected to x-ray treatment. The results of the treatment are shown in table I.The results show that the x-ray treatment did not produce significant changes in the case of radishes. The improvements in weight of the plants from treated seeds as compared with those from untreated is not very large, and may therefore be attributed to accident. Moreover there is no significant difference between the weight per pod of the seeds exposed when sprouted and those exposed when dry. The increase on the average is only about 10 per cent. which cannot be considered to be very important.In the case of beans, plants from seeds treated dry have shown no significant changes over the untreated. However, plants from the irradiated sprouted seeds have shown increases of some 25 per cent. over the controls, which is probably too large to be considered accidental.The results were more interesting in the case of lettuce. While the increase in weight was not significant in the case of most of the plants produced from seeds treated in the dry state, the five-minute dose produced an increase in growth of about 60 per cent. over the controls. Because of this large increase, the experiments were repeated a year later. The results indicated 209 www.plantphysiol.org on May 9, 2018 -Published by Downloaded from
A detailed hematological delineation of this new entity is in progress. Physicochemical investigations to further characterize the new hemoglobin component are also in progress. The assistance of the Hematology Clinic of the Children's Hospital of Detroit in many different aspects of these studies is gratefully acknowledged.
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