Submitter here: Leaving aside the question of whether or not this constitutes learning, which may be as good a word as any, I posted this in hopes the HN collective mind would offer other explanations for the observed results, perhaps even shedding light (no pun intended) on the mechanism. As stated in TFA, our findings raise some obvious questions about the underlying physiological/molecular mechanisms by which plants can integrate environmental and internal cues and coordinate complex patterns of information during associative learning, so that a more effective, even adaptive, behavioural response can be expressed.