Plant sentience and the case for ethical veganism

Does the possibility of plant sentience pose a problem for ethical veganism? It has not yet been demonstrated that plants are sentient (i.e., they can feel). Moreover, even if it were could feel, would also have to be feel affectively “valenced” feelings ethically significant, such as pain and fear, rather than just neutral sensations darker/lighter, or wetter/drier. Finally, valenced feelings, veganism likely still option, on principle causing least harm.