Effects of Acute and Chronic Gamma Irradiations on In vitro Culture of Anubias congensis N.E. Brown

Abstract

Plantlets of Anubias congensis N.E. Brown cultured on MS medium were irradiated with gamma rays for both acute and chronic treatments of 0, 20, 40, 60, 80 and 100 Gy at a dose rate of 264 Gy/hr (acute) and 0, 14.34, 28.60, 31.24, 42.90, 51.16, 65.55, 82.42, 91.69, 105.99 and 120.30 Gy at a dose
rate of 0.71 Gy/hr (chronic). The calculated LD₅₀₍₆₀₎ for the acute irradiation was 32.12 Gy. It was not possible to calculate the LD₅₀₍₆₀₎ for the chronic irradiation because the survival rate was 100% for all treatments. Following acute gamma irradiation, the number of roots, number of shoots, number of leaves, length and width of leaves and length of roots in the M1V1 generation of A. congensis N.E. Brown plantlets were less than the control. With chronic gamma irradiation, there was no difference in most parameters with the exception of the 105.99 and 120.30 Gy treatments, in which the number of roots was greater than the control. Some abnormalities observed in the M1V1 generation exposed to acute irradiation that were genetically transferred to the M1V3 generation included narrow leaves, undulate leaf margins, and dwarfism with light green leaves. The mutation frequencies for these characters were 11.67, 26.67 and 6.67% for a dose of 20, 40 and 60 Gy, respectively. For the samples exposed to chronic irradiation, mutations observed in the M1V3 generation were dwarfism and albinism. The mutation frequencies were 1.67, 1.67, 3.33, 5.00, 11.67 and 10.00% at a treatment dose of 14.34, 28.60, 31.24, 91.69, 105.99 and 120.30 Gy, respectively. No mutation could be detected in the M1V3 generation irradiation with chronic gamma rays at 42.90, 51.16, 65.55 and 82.42 Gy. The potential mutants of A. congensis N.E. Brown in this research were the undulate leaf margins and dwarfism with light green leaves. All the mutation characters were maintained through tissue culture.