Effect of different intervals of x-ray split doses on shoot production of in vitro derived explants of Gerbera jamesonii Bolus

Full text: Linearity between rising x-ray doses and mutation rate is limited by the simultaneously increasing radiation damage; induced chromosome aberrations eliminate valuable factor mutations. The application of fractionated doses provides the opportunity for repair of a distinct portion of damage. The dose of 30 Gy was fractionated into two identical parts. The periods for repair were 0.5 to 48 hs. The absolute and cumulative number of post-irradiation regenerated axillary shoots on 4 subsequent dates of cutoff were used as parameters to estimate radiosensitivity. From an economical point of view the interval of 4 hs between two dose fractions may be recommended for practice. (author)