It is no problem at all having plants in a tank that is being cycled using ammonia. The plants will use some of the ammonia as plant food because it is their favorite form in which to take in nitrogen. Most plants would rather have ammonia than nitrates. That means the ammonia will slowly go down even if you have no bacterial action yet. It is not a problem, you just top it back off once a day and your cycle will go on as if the plants were not there. If you later have confusing readings, just be sure to mention that you have the plants so we can take that into account while analyzing whatever problems you may have.
