Oh yeah. This is a favorite. Also, remember that plants prefer
classical music to rock music, and that you have to be careful which
plants you put by your crystals so their vibration frequencies don't
interfere with each other. And above all, don't interact with your
plant when you're feeling down or angry, because your bad ju-ju will
infect it.

The short answer is that we cannot measure "feelings" in plants, so
science cannot answer the question of whether they have them. They
certainly don't have them in the same way that we do.

Your coworker's claim is more one about an understanding (or
misunderstanding) of science than about plants.

I wouldn't argue with the person, but if you must, I suggest that you
ask what he or she means by "feelings" and their presence can be defined
in plants in an observable fashion. Here are some possibilities...

1. If to have feelings requires nervous systems like ours, then plants
definitely don't have them. We can see that.