Oxygen is not produced during photosynthesis by
Cycas
Nostoc
Green sulphur bacteria
Chara
Explanation:
Green sulphur bacteria do not use $H_{2}O$ as source of proton, therefore they do not evolve $O_{2}$.
Green sulphur bacteria do not use $H_{2}O$ as source of proton, therefore they do not evolve $O_{2}$.