Spin-trapping ESR method was used to study a novel NO formation pathway in higher plant chloroplasts with Fe 3+ （MGD）2 as a NO trap. The oxygen evolution complex （OEC） of the chloroplasts was treated with TEMED,and the electron donor DPC was provided to recover the electron transfer chain. Under anaerobic conditions,NO -2 was reduced by strongly illuminating chloroplast to form NO. However,when kept in dark or when illuminated without DPC,no NO signal could be detected in the reaction system. The results show that the formation of NO is closely related with the light-induced electron transfer in higher plant chloroplasts. [WT5HZ]
