Effects of kinetin and succinic acid seed dressing on the ultrastructure of chloroplasts and chlorophyll fluorescence parameters in aging process of maize

In order to investigate the effects of kinetin (KT) and succinic acid (SUA) on the chloroplasts ultrastructure and function, the ultrastructure of chloroplasts and chlorophyll (Chl) fluorescence characteristics were studied for two genotypes with KT and SUA seed dressing under pot experiment. The results showed that KT and SUA inhibited the production of osmioplilic granules in order to maintain the structure of granum thylakoid integrity, which resulted in the increase of the chlorophyll and car content, the ratio of Chl a/b. KT and SUA also promoted the Fv/Fm and PSII values by 7.8% and 6.2%, 10.2% and 2.7% at the 1/2 leaf yellow stage of Zhengdan 958 and Yudan 2002, but reduced the qN and qP values. Compared with Yudan 2002, normal senescence variety Zhengdan 958 was more excellent on the chloroplasts ultrastructure, chlorophyll content and fluorescence characteristics.