Applications of radioisotopes and radiations in tracing, radiography, food preservation, sterilization, eradication of insects and pests, medical diagnosis, and therapy hold tremendous promise, particularly for societal welfare. However, in the case of a nuclear disaster or the event of extreme radiation pollution due to anthropogenic activities, the direct and indirect effects of radionuclide and radiation transfer in the soil–plant–air ecosystem. This mishappening affects every component of the food chain. Furthermore, it also becomes significant because we frequently forget the fact that radiations released by any radioisotope interact with matter and can modify its biochemical, biophysical, and biological features, although they cannot be seen or felt. In this regard, the interaction of ionizing radiation with plants and the resulting biological consequences is poorly understood, with existing data being scarce, fragmented, and inconclusive. At the plant level, changes can be observed at the morphological, biochemical, physiological, and/or biophysical levels, with the amount of the change being highly dependent on the exposure dosage, soil, farm management, and other environmental factors. Therefore, the current chapter aims to compile the existing research on how radiation influences plant morphology, molecular biology, physiology, and diversity.