16 



14 



12 



I 10 

 o 



8 h 



6 



4 



2 





 UNEXPOSED 250 750 2000 8000r 



450 - 



\- 400 - 

 3 350 



Q. 



(T 300 



UJ 



^ 250 



C/) 



S 200 1- 



V) 



o 

 6 



150 - 

 100 - 



1 — r 



± 



J L 



50 



UNEXPOSED 250 



Jl 



750 



2000 8000 r 



FIGURE 7. The change in the number of seeds 

 depending on the X-ray dosage used. 



FIGURE 6. Number of ears and weight of seeds 

 per plant in controls and in irradiated rye. 



or diseased, while in plants receiving 250 r, 

 only 63. 7 out of 446. 5 seeds, 35. 5%, were 

 diseased. This indicates an increase not only 

 in quantity of yield, but also in quality. If we 

 add to this what we know about the increase of 

 weight of seeds, then the full significance of the 

 proper use of X rays to agriculture becomes 

 evident. 



Turning our attention now to the total weight 

 of the seeds, we see that 250 r triples the 

 weight, that exposures of 500 and 750 r keep it 

 on the same level, and that only beginning with 

 1000 r does the weight begin to regress (with 

 4000 and 8000 r it is nearly half that of the con- 

 trols). Thus, a dose of 8000 r has a strongly 

 depressing effect on the number of ears and the 

 weight and number of seeds; in addition, it in- 

 creases the number of underdeveloped and 

 diseased seeds (Fig. 6). 



Looking over the data for every individual 

 plant for each of the doses, we find great indi- 

 vidual variations. Thus, the number of ears 

 can vary from 2 to 24; the number of normal 

 seeds, from 17 to 930; the total weight for any 

 one plant, from 1. 06 to 36. 26 grams. This 

 great variability is characteristic not only of 

 rye, but of all other plants which are subjected 

 to the action of X rays, as can be seen from 

 the literature. If we turn to variability in num- 

 ber of ears, the first thing that strikes our 

 attention is the large number of secondary stems 

 on irradiated plants, which did not have time to 

 come to maturity. These secondary stems, in 

 turn, increase the number of underdeveloped 



seeds and thus lower the total seed weight for 

 a single plant. ^ If we are unable to answer 

 definitively at this time the question of why 

 irradiated plants have so many secondary stems 

 that do not reach maturity, we can at least con- 

 jecture. Apparently, X rays, by stimulating 

 development in plants, open up possibilities 

 which in normal plants are latent. However, 

 these possibilities never reach full development 

 because something is missing from the environ- 

 ment, and this results in the incomplete devel- 

 opment of all stems and ears. What is missing 

 (nourishing elements in the soil, or light, or 

 heat, or all of these) we cannot tell at this time. 



From our preliminary data it is quite obvious 

 that X rays act as stimulants to the development 

 of rye. If we compare all the curves by which 

 growth, development, and yield of irradiated 

 plants are reflected, we see that they coincide. 

 The initial height of the plants, diameter of 

 rootlets, number of stems, number and weight 

 of the seeds — all act in a similar manner under 

 irradiation. Radiations of 250 r send the curves 

 up steeply; 500 and 700 r continue this tendency, 

 but with doses of 1000 r the curves begin to 

 drop. 



At this point it seems appropriate to point 

 out once more the necessity of carrying through 

 experiments with irradiation of seeds or sprouts 

 until the plants mature; otherwise, it is possi- 

 ble to obtain an incorrect impression of the 

 effect of X rays. If we had carried our experi- 

 ments only up to the point where plants were 

 beginning to bush out, we might have come to 



* Translator's note: The word "total" may be incor- 

 rect; the author probably meant "average" weight. 



20 



