232 HIDEO KOIIUEO- 



uot accept G. ScffWAKz's results, though the water content' of his seeds wa9 

 not known. That is, in the writer's experiment, even in the air-dried seeds, 

 if their water content be about 14=%, they are aöected, and the impediment 

 in growth obviously appeared at 80 H and up. The 80 H-plants were stunted 

 so badly that only 15 grains of seeds were obtained from 3 plants, i. e., 

 only stout individuals developed so far that they bore fruit. But the 150 H- 

 seeds germinated and developed to seedlings, the radicle reaching 2-3 cm under 

 the groimd. Thus the writer verified Koeenicke's result. 



IV. Germination Experiments. 



They were performed ou the seeds of " Hyogo," a race of Vicia /aba 

 (1918-cix)p), in Experiments VIII and IX. 



As to the irradiation for these two experiments, the same care was tiiken 

 as in the case of othei«; the only dilfcrence being that the tube distance 

 was 15 cm. in this case. 



EXPERIMEXT YIII. 



In order to see if the presence of a seed coat affects the sensibility to 

 Röntgen rays and if there is acceleration of germination in steeped irradiated 

 seeds, this germination experiment was performed. The seed coat of a part 

 of these seeds was peeled so as to uncover the plumule and radicle, and then 

 these peeled and un]^)eeled seeds were exposed to the rays of 20 H, 40 H and 

 50 H at the same time. The tip of the radicle of peeled seeds became brown 

 by the iiTadiation. They were sown 2 and 4— homrs after irradiation in a 

 square pot, with washed sand, and divided into four compartmente. The 

 same nimiber of conti-ols, as 20 H-, 40 H- and 50 H- seeds, peeled and unpeeled, 

 were placed in these four sections of the pot. The writer us.^d two sets of 

 these pots, and placed them near a window on the south side of a con-idor. 

 One can keep environmental conditions faiily constant in sowing them in a 

 ix)t, but can not do so in the field. 



1. Absolutely dried seeds by "water-bath" have uo power of germination; the writer's 

 experiments of this kind by using the seeds of ]'kM fabii, Oryxi sativa and Phaseolus wlgaris 

 gave always negative results, so the seeds (trockene Samen) of Schwarz may not have been of 

 such nature, and, perhaps may not have contained Uss water than air-dried seeds. 



