Hmm that is an interesting point. I wonder what the cutoff energy for photosynthesis is.The proper answer to this question depends on the energy of the radiation we are discussing. Yes, gamma (high frequency) radiation will harm it just as gamma's will harm us; the degree of harm a plant will experience as compared to a person I do not know.
I point out the energy of the radiation because if we are talking about lower energy (lower frequency) radiation in comparison to gamma, then the plant will undergo photosynthesis which is vital to it staying alive.
The answer to your question nuclear-boy, requires a yes/no type answer, and in both scenarios I have just provided, and any other way you want to look at the question ('does radiation affect plants?'), all answers are "yes".
Plants use light between 400-700 nm wavelength (or 1.7-3 eV), i.e. the same energy level that we see with our eyes. Gamma radiation is way shorter in wavelength (more energetic) with energies of keV to MeV.Hmm that is an interesting point. I wonder what the cutoff energy for photosynthesis is.