Photosynthesis is the unique function of higher plants , green algae and cyanobacteria , which is the greatest turnover powered by light energy on our planet . psii functions as a water / plastoquinone oxidoreductase in the thylakoid membrane of chloroplasts and cyanobacteria , comprising one of the light reaction centers for photosynthesis 光系统( ps )是绿色植物光合膜上存在的两个光反应中心之一,具有利用太阳光的能量来裂解水、释放分子氧并还原质体醌的功能。