Answer :
Based on the situation, the perception following two weeks is that the plantlet kept in daylight makes due as it can orchestrate its own particular food.The plantlet in the oxygen chamber passes on as it doesn't get carbon dioxide and can't integrate its own nourishment.
Plantlet need carbon dioxide and sunlight to complete the process of photosynthesis. While both have a source of light they are not getting every source needed to make their own food. Since the plantlet in the chamber is not getting carbon dioxide it may not grow as fast as the one kept outside of it.