CHANGING PLANT LIFE

Evening Star, Issue 19796, 21 February 1928, Page 3

CHANGING PLANT LIFE

X-RAY EXPERIMENTS VARIATIONS PRODUCED If the X-ray has produced important variations in the characteristics ot plants and insects, and if these variations are transmitted by heredity to the next generation, may not the X-ray on the human organism produce equally important .variations that may likewise bo transmitted to posterity as hereditary characteristics H This question was propounded to Professor Thomas H. Goodspeed, of the University of California botany department, who, with Professor A. R. Okon, has been conducting a long scries of experiments on the effect of X-raying the sex cells of plants. Some of the results of these expriments have recently been announed in the Press, and their ultimate importance may prove to be very great, not only for ’plant physiology, but for human beings. ■ Speaking to a ‘ San Francisco Chronicle representative, Professor Goodspeed says that so far there are no known results from observations conducted on human beings to favor the idea that variations can be produced by the application of X-rays to human sex cells similar to those produced in ex-, periments with plants. ... “We want to keep off subject of human beings in this work,” he said. “ Not being a zoologist, I have no opinion on the subject. Biologists in general have been for a long time extremely anxious to find some method of producing variations in organic characteristics at will. We know that variations are produced in Nature, and a part of what we call evolution is simply an accumulate i of natural variations over a long period of time. “The tobacco plant was chosen ns a subject for experimentation chiefly because it grows well in Berkeley and matures fairly rapidly. By using the greenhouse we are able to get two generations a year. There arc many sharply distinct species, the flowers are largo and easy to work with, and the celt anatomy of Ike various species is valuable for experiments in variations of hciedity and evolution. “Over 1,000 plants have been grown from X-rayed sex cells, and among these there are over 200 whose external appearance is remarkably modified. In some of the plants only one characteristic has been changed, such as the flower shape or color, the leaf size, etc. Other plants showed changes in every conceivable plant characteristic. Aggregations of plants never before seen by anyone have been produced that had originally come from perfectly stable types. “ The results wore not always an improvement: sometimes they‘were the reverse. The important point is that change has been produced One thousand plants have been grown, which represent perhaps a fair sample of the effecls of X-rays on sex cells. But in order to prove whether the progressive or regressive effects are more striking wo shall have to grow 10.000. “Some plants showed improvement, others were throw hacks. Many plaids did not seem to be chan"®! at all, but.we may expect to find marked changes in the next generation, in which results often appear. In the regressive types we found that the X-rays had vitally affected the • structure, quantity, and arrangement of cell tissue. On examination under the microscope some of the nuclei of cells containing hereditary material were found to be highly abnormal. Other plants in the improved types had normal nuclei. “No law has been worked out to predetermine the. results of such experiments, but we know that a means has been found to produce variations at will. The meihod is all-important, and I here is no limit to the field for future experimentation.”