Chromosome Pairing in X-irradiated Pteris longifolia L.

Abstract

Effects of X-irradiation on pairing of chromosomes in R₁ Pteris longifolia is reported. Selfed one leaf sporophytes have been irradiated to a dose ranging from 2 Kr to 10 Kr. Irregularities in pairing behaviour of chromosomes during meiosis associated with fragments have been observed in the irradiated plants. The observations have been discussed in the light of informations available from higher plants. The cause for such abnormalities are attributed more to the physiological disturbances in the cell than to the fragment of the chromosomes. Translocations have not been observed. This information has been obtained from irradiated sporophytes of selfed Pteris longifolia, the tetraploid sexual species of ferns for the first time.