What might happen at the cellular level of the plant if there was no water available for photosynthesis?

when water levels are low due to water stress, photosynthesis can slow or even stop, causing internal food supplies vital to other processes to diminish or disappear -- yellowing may also occur if photosynthesis stops completely.

Explanation:

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.