The photoreceptors, i.e., rods and cones, are specialized neurons located in the retina. These cells convert sunlight into electrochemical signals which are interpreted by the central nervous system. The cGMP-gated channels that are expressed in photoreceptor plasma membranes have a major role in this process by regulating the flow of sodium (Na+) and calcium (Ca2+) ions in the outer side of the membrane via changes to cyclic guanosine monophosphate (cGMP) levels which are induced by light. In the dark, high cGMP levels maintain channels in an open state, thereby allowing the passage of Na+ and Ca2+ ions to flow into the outer segment of photoreceptors in order to maintain them in a depolarized state.
It might not be a good idea as nitrogen may be needed by plants in several cellular processes and eliminating nitrogen uptake might severely impair these functions if there are no alternatives to these pathways
