Effect Of Light On Synthesis Of Anthocyanin And Quality Of Tuber In Purple Potato

In order to study the effect of light on synthesis of anthocyanin and quality of tu ber in purple potato.In this research, "Black Beauty", "Kawa Aya No.1" and "Rongziy u 5" were used as experiment materials,with the treatment of altitude regions(Beichuan, Youxian and Wenjiang District).The light hours (2 hours and 4 hours,2 hours was t he average light hour in Chengdu plain in autumn and was used as the variable and t he illumination time of 2h was from 12:00 to 14:00 while that of 4h was from 11:00 to 15:00) and light intensity (3000 lx、6000 lx、9000 lx as weak light, medium lig ht and strong light, respectively), and the growth characteristics,anthocyanin containme nt,anthocyanin accumulation,phenylalanine containment, phenylalanine ammonialyase acti vity (PAL), chalcone isomerase activity (CHI), dihydroflavonol 4-reductase activity (DF R) and flavonoid glucosy transferase activity (UFGT) in purple potato tuber were be e xamined, to study the effect of light on anthocyanin containment, regulation of related enzyme activity and tuber quality.The mainly results as follows:(1) Effect of different altitude regions on anthocyanin containment in purple potato. Color changes of tuber in purple potato harvested in different altitude regions show the same law. The color in Beichuan was the deepest, followed by the potato color in Wenjiang, and the color in Youxian was the shallowest. "Rongziyu5" as an example,the anthocyanin containment of tuber harvested in Beichuan was 3.37 mg/100 g, which is respectively higher 24.96% than the result from Youxian, and 17.26% than it in Wenjiang.(2) Effect of light on synthesis of anthocyanin in purple potato. under the condition of 2h, the anthocyanin containment of purple potato tuber at maturity stage in treatment of strong light, medium light and weak light was 3.10 mg/100g,2.95 mg/100g and 2.83 mg/100g while under the condition of 4h, that was 3.26 mg/100g、3.05 mg/100g、2.74 mg/100g, respectively. The anthocyanin containment, anthocyanin accumulation, phenylalanine containment, activity of PAL, CHI, DFR and UFGT in treatment of strong light and medium light were increased in various degrees than that in treatment of weak light in different light hours.(3) Relationship between anthocyanin containment and related enzyme activities, the anthocyanin containment were positively correlated with PAL,DFR,CHI,UFGT activity. The correlation between anthocyanin content and CHI activity reached a very significant level. The correlation between anthocyanin content and DFR activity reached a significant level.Correlation coefficient from high to low in order for CHI> DFR> UFGT> PAL, The relationship between anthocyanin synthesis was most closely related to CHI activity in purple potato tuber.(4) Effects of light on the growth and quality of purple potato. The contents of soluble sugar of tubers in purple potato harvested from three different altitude regions from high to low in order for Beichuan> Youxian> Wenjiang, The dry matter content and starch content of tuber in "Black Beauty" and "Kawa Aya No.1" purple potato varities harvested in Beichuan were more than that in wenjiang. Increase the light intensity during the whole growth period, the tuber number, stem fresh(dry) weight, leaf fresh(dry) weight, starch containment, soluble sugar containment will be increased.Through the research, it is suggested that light is the main factors which affect the anthocyanin content of tuber in same purple potato varieties. Increasing the intensity could improve anthocyanin content, key enzyme activity of anthocyanin biosynthesis. It could be that light as a signal molecule regulating the key enzyme activity of anthocyanin synthesis to influence anthocyanin content in tuber, the specific regulation mechanism needs to be further studied. The development of this experiment provides a theoretical basis for further study on the mechanism of anthocyanin biosynthesis of tubers in purple potato, and provides a reference for the rational selection of production areas in the practice of purple potato production.