Studies On The Component And Spectra Characterization Of Thylakoid Membrane And The Transcription Of Photosynthesis Related Genes The Cotyledon Of Oilseed Rapes During Dark-induced Senescence

Photosynthesis is the unique function of the green plants. The photosynthetic apparatus is composed of various complexes. To analyze the effect of light on the development, structure, composition and function of the chloroplast, we carried out a comparative study on cotyledon and thylakoid membranes between dark-induced and its normal oilseed rape during cotyledon development. The results showed that in the dark induced cotyledon, Chl and Car content decreased consistently. The same change pattern was also appeared in the major light harvesting protein LHCII trimer. Chl (Chl a and Chl b) was lower in thylakoid membranes from the dark induced type in the same time point than those from its normal type. Furthermore, the chlorophyll fluorescence spectra indicated, on contrary to that in normal type, the capacity of harvesting light and being excited were lower in the dark induced type. In addition, composition of proteins on cotyledon thylakoid membranes also changed in the dark induced type, suggesting by significant difference in protein fluorescence, and SDS-PAGE between these two kinds of thylakoid membranes. In the dark induced type, the transcription of genes, such as rbcL, rbcS were lower than those in normal type, especially the rbcS. Above all, the cotyledon of oilseed rapes began to senesce when put them in dark for 1 day. Lower content and the spectra peaks of thylakoid membranes and the mRNAs refers to photosynthesis were made by dark induction.