Abstract: Oxygen-eyolving PSII particles were prepared from soybean chloroplasts wiht detergent Triton X-100. The oxygen evolution activities rea-ched 208 umol O2 mg-lchl. hr-1. PSI-dependent O2 uptake and fluorescence emission peak F735 which contributed to PSI were decreased obviously. Light- induced P700 signal was hardly detected and we can't isolate any chlorophyll- protein complex band belonging to PSI using SDS-PAGE. The DCIP photore- duction activity was high. The Chl a/b ratio of the particles was about 1.9. The results cited above show that the soybean particles were enriched in PSlI and oxygen-evolving system and its PSI content is neglectable. Some photosynthetic characteristics of similar particles from spinaeh and castorbean chloroplasts were also showed.

Key words: characteristics, oxygen-evolving, photosystem