Figure 3

The atrad21.1 atrad21.3 double mutant is more hypersensitive to DNA dsb damage than atrad21.1 . Both the atrad21.1 atrad21.3 double mutant and the atrad21.1 single mutant are hypersensitive to exposure to ionising radiation (150 Gy), being the former more hypersensitive than the latter; as observed in different experimental replicas. In contrast, the atrad21.3 single mutant reaches a development stage more similar to Col, even after exposure to 150 Gy of ionising radiation. The differences in development are highlighted in the blown up images (3× magnification) of seedlings after exposure to 150 Gy of ionising radiation. These illustrate the predominant double mutant seedlings’ phenotype; development arrest and senesce at an early developmental stage, namely in seedlings with none or one true leaf. These blown up images also show that atrad21.1 seedlings experience severe development delay, yet not as severe as in the double mutant (seedlings bear more true leaves than the double mutant). In both the single and double mutants, some plants manage to develop further, forming more true leaves. All seedlings were germinated from irradiated imbibed seeds exposed to 150 Gy of γ-rays (0.7532 Gy/minute +/− 0.003 Gy/minute; source: Cs137) and photographed 30 days after. 0 Gy - not exposed to ionising radiation. Col - wild-type Columbia-0 plants.