CHANGING PLANT LIFE

Hawke's Bay Tribune, Volume XVIII, Issue 47, 7 February 1928, Page 9

CHANGING PLANT LIFE

X-RAY EXPERIMENTS. VARIATION PRODUCED. If the X-ray has produced important variations in the characteristics of plants and insects and if these variations arc transmitted by heredity io the next generation, may not the Xray on the human organism produce equally important variations that may likewise bo transmitted to posterity as hereditary characteristics? This question was propounded tu Profes aor Thomas H. GootUpeed, of the University of California botany department, who, with Professor A. R. Olson, has been conducting a long series of experiments on the effect of X-ray-ing the sex cells of plants. Some of the results of these experiments have recently been announced in the Wess, and their ultimate importance may prove to bo very great, not only for plant physiology, but for human beings. Speaking to a << San Francisco Chronicle” representative. Professor Goodspeed says that so far tnere are no known results from observations conducted on human beings to favour the idea that variations can be produced by the application of X-rays to human sex cells similar to those produced in experiments with plants. “We want to kecj off the subject ofhuman beings in this work.” he said. “Not being a zoologist, 1 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 accumulation of natural variations over a long period of time. APPEARANCE OF PLANTS MODIFIED. “The tobacco plant was chosen as a subject for cxperimen ation chielly because it grows well in Berkeley and mat.lies fairly rapidly. By using the greenhouse, we are able to get two generations a year. There are many sharply di&unct species, the flowe-is arc large and easy to work with, and the ceil anatomy of tiie various species is \aluable for experiments m variations of heredity and evolution. “Over 1000 plants have been grown from X-rayed sox cells and among these there arc over 200 whose exceinal appearance is remarkably modified. in some of the plants only one characteristic has been changed, such as the flower shape or colour the leaf size etc. Other plants showed changes in every conceivable plant character istic. Aggregations of plants never before seen by anyone have been produced that had originally come from perfectly stable types. “The results were not always an improvement; sometimes they were the reverse. The important point i? that change has been produced. One thousand plants have been grown which represent perhaps a fair sample of the effects ot X-rays on sex cells. Bui in order to prove whether the progressive or regressive effects are more striking, wc shall have to grow 10.00. ‘•{Some plants showed improvement other were throw backs. Many planU did not seem to be changed at all, bui wc may expect to find marked changes in the next generation in which re suits often appear. Jn the regressive types we found that the X-rays had vitally affected the structure, quantity, and arrangement of cell tissue. On examination under the miscroscope, some of the nuclei of cells containing hereditary material were found to lie highly abnormal. Other plants in the improved types had normal nuclei. “No law has been worked out, to pre-determine the results of such experiments but we know that a means has been found to produce variations at will. The method is all-important, an l thv* , «! is no limit to the Held for future txperimentation. n