5. Translocations from ultraviolet. In a population from pollen treated with ultraviolet 9 decidedly off-type plants (in addition to marked deficiencies) were examined. Presumably all were deficient, though the deficiencies were not marked. The diakinesis configurations were as follows:
5 plants had 10 II; 2 with obvious deficiencies.
1 plant had 8 II and a ring of 4, a typical interchange complex.
1 plant had 7 II and an open complex of undetermined number.
2 plants had 9 II and a 3 chromosome open complex.
In each of these last two plants with a 3 chromosome complex a chromosome bridge was frequently seen at anaphase I, and segregations of 9-10, 10-10, and 9-11 were observed. The diakinesis configurations and anaphase segregations can be explained on the hypothesis that two chromosomes with terminal deficiencies have united to form a single chromosome with two adjacent centromeres, the terminal portions having been lost. This hypothesis depends on the assumption that such a chromosome could persist through the life of the plant.
Lillian Hollingshead Hill