The process of absorbing stagnant carbon dioxide molecules in the air and using saturated plant vacoules to emulate synthesis in complete darkness. In theory, you wouldn't produce as much glucose from this as photosynthesis does. As a comparison, think of aerobic and anaerobic respiration for example. Anaerobic doesn't produce as much ATP as aerobic respiration does, and can lead to lactic acid built up as a result. If evolution has shown us anything its that organisms can adapt to their environments a. k.a. survival of the fittest. I would believe after exposure to complete darkness for millions of years, plants would be able to grasp adaption or, they would all die out. Chemo Synthesis is an example of organic adaption, which was only discovered about 10 or more years ago.
Shadow Synthesis Theory explains how plants have had to use Shadow Synthesis in the past to make glucose when the dinosaurs when extinct, which could explain why plants still exist today.(flawed)