280 



UADIATION BIOLOGY 



are prohalily more than 10 times as effective as wave length 207 m^ and 

 probably more than 100 times as efTective as wave length 802 in/i. in terms 

 of ('(|ual int(Misity at the surface of the sperm inicleus. 



Tablk 7-7. Tnio Fbequency of Endosperm Deficiencies in Maize as a 



Function ok Wave Length at Two Different Doses 



(Stadlor and Tber, 1942.) 



In the comparison of wave-length effects in Sphaerocarpns, complication 

 from internal filtration is at a minimum, for the spermatozoid irradiated 

 consists almost entirely of nuclear material. Knapp ei al. (1939) com- 

 pared the effectiveness of six wave lengths in inducing genetic alterations 

 in Sphacrocarpus donncllii. The spermatozoids were irradiated in water 

 suspension, and the sporogonia produced by fertilization of untreated 



Table 7-8. The Frequency of Induced Mutations in Sphaerocarptis as a 



Function of Wave Length, Dosage 2 X 10' ergs/mm* 



(From Knapp ei al., 1939.) 



female gametophytes were tested by analysis of the spore tetrads. 

 Mendelizing mutations were identified by the production of two normal 

 and two mutant plants; lethal "mutations" (i.e., all genetic alterations 

 w'ith haplo-lethal efTect), by the production of only two instead of four 

 plants by the spore tetrad. By the tetrad analysis of 50 to 75 sporogonia 

 representing each treatment, it was possible to show sharp differences in 



