RADIUM AND PLANT SEEDS

Evening Star, Issue 20428, 8 March 1930, Page 28

RADIUM AND PLANT SEEDS

1 1 the ell'oct of the application of radium to tlio human body is stilt in the empirical stage, ‘it is safe to state that even less is known of its effect on plant iiii-Mt points winch emerge from the exploratory work that has boon clone so far in both fields is a realisation of the difference in the reaction of individuals to identical emanations (savs the ‘ Gardener’s Chronicle.’ London). ' A radium application that may stimulate the tissues of one person’s body may have a destructive effect on those of another person; and it is the same with the or plants. In fact, one of the investigator’s difficulties is the determination of the correct dosage for the end in view. The point is well illustrated in the course of the investigations in progress at the University of California on the clfect of radium on the seeds of tobacco plants. In the course of the experiments, some two hundred and fifty of these seeds were attached to the inside of a gelatine capsule of the type employed by medical men in the administration of drugs, and the capsule was placed in a glass tube, which, in turn, was covered by a leaden tube whereof the walls were sufficiently thick to blanket the rays of radio-active needles * winch were packed round its outer diameter, except the gamma rays. These ate the high velocity rays used by practititioners in the treatment of malignant growths in the body, and they have the power to cause vital changes in the tissues and cell protoplasm, both lor better and worse. Except where the dosage was excessive enough to kill the embryo, the main elfcct of the rays was a pronounced retardation of the subsequent germination of treated seeds; this was so marked that the seeds in the control plot showed almost complete germination before more than a few of the treated seeds exhibited any sign of life.

intimately, however, germination IH'oeeoclerl normally in the ease of the irradiated seeds, and then there was nothin*,; to distinguish the mature plants in either batch Irom each other. If the treatment is withheld from the seeds until germination has nomine need the effect of even u relatively light dosage is very marked, not only in the complete destruction of many embryos, hut in the distortion ol the tissues of those which, survive. But that is not the end of this interesting series of experiments, for later generations of irradiated plants may show changes ill the size, shape, and colour of both flowers and leaves; moreover, it seems that some of these changes may persist without modification, so that future generations inherit them. If this interestingdiscovery should he confirmed beyond the region of doubt, it opens up a vista of undreamed of possibilities in the evolution of new plant forms. In the case of the seeds of the tobacco plants which formed the subject of the experiments, the colour of the .seedlings of red-flowered plants was found to vary from light pink to pink and on to dark red and purple. The tube of the llowcr, too, varied, and in some cases was longer than that of the parent, and the petals were- sometimes broader» the leaves were subject to alteration in shape and texture, and the whole plant might he changed. In one hatch of seedlings from irradiated seeds, there might, he giants and dwarfs, plants of long-branched habit ami plants of columnar growth. These changes are brought about in the first instance by the absorption of the rays at the points of growth ol the embryo or the seedling, and apco the technique of the administration of the rays is understood, it may bo that the scientists will have it in his power to produce a definite and lore-known alteration in a plant. As yet and, perhaps, happily, we are a long way from that cufmiiialion, but that does not detract from the interest and value of the researches Dr Goodspecd and his coworkers. have in hand at the Stanford University.