Effects of Photoperiod on the Content of Flavonoid Carotenoids and Expression of Synthesis Related Genes in Embryogenic Callus of Longan

[Objective]To study the effects of different photoperiods on the accumulation of flavonoids and carotenoids,on cellular enzyme activities and flavonoids and carotenoid synthesis related genes in embryogenic callus of Dimocarpus longan. [Method]Using loose embryogenic callus of D. longan as material,five kinds of photoperiod treatment on the accumulation of flavonoids and carotenoids in longan embryogenic callus were studied. Photocycle processing was as follows:full light 24 h/0 h L/D,long light18 h/6 h L/D,semi-light 12 h/12 h L/D,short-light 6 h/18 h L/D,total darkness 0 h/24 h L/D.The effects of different photoperiod processing on cytoprotective enzymes changes and expression of genes involved in the synthesis of flavonoids and carotenoids were studied also. [Result]The content and yield of flavonoids in embryogenic calli of longan were the highest in short-light treatment,and the hightest carotenoid was treated with 24 h/0 h L/D.The expression trends of SOD,POD and H2 O2 were consistent result under different photoperiod treatments.The PRO content was only higher in the highest period than in the dark period of the control group.The PAL content was highest at in short light,which was consistent with the highest accumulation of flavonoids at 6 h/18 h L/D. The flavonoid synthesis genes CHI and CHS under the photoperiod treatment were "M" expression patterns,and DFR and F3 H were inverted "V" expression patterns.But the four gene expression patterns used for carotenoid synthesis vary. [Conclusion]This study showed that photoperiod regulates the accumulation of flavonoids and carotenoids accumulated and the expression of its synthesis-related genes in the embryo-genic callus of D. longan.