Hi Rachel,

Thanks for your fascinating question! Unfortunately, I do not have any direct answer for you, only indirect information that may or may not apply to kale at the growth stage you are referring to. My (unreliable) guess would be that the process of senescence and nutrient reallocation away from leaves would indeed have begun during flowering for a bolting plant like kale. But I would also guess that one could go by loss of chlorophyll content (relative yellowing) to be a rough guide as to how much senescence has progressed. Senescence researchers would have much more to say about this! A quick note on flowering ‘hormones’ – while gibberellins do promote flowering in many plants, the mobile molecule that is most associated with controlling the switch to flowering is actually a protein (AKA a polypeptide macromolecule). The gene that encodes this protein was aptly named Flowering Time and the protein is often called FT for short.