Photoeffects Of Anthocyanin Synthesis In Suspended Roselle (Hibiscus Sabdariffa L.) Cells

Light irradiation is one of the most important external factors that regulate anthocyanin synthesis in Roselle (Hibiscus sabdariffa L.)cells.In Roselle suspension culture,light irradiation controlled the anthocyanin yields ,but had no significant influences on cell growth, pH change ,or sugar consumption.Roselle cells did not produce anthocyanin when cultured in darkness, the anthocyanin content in cells was dropping due to the dilution by cell growth and the total anthocyanin content in result culture equaled to that of the beginning which was brought in by cultivation. That meant that anthocyanin in Roselle cell growing in darkness was not distroyed .With the irradiation intensifying, both anthocyanin synthesis rate and yield were enhanced, however with the light intensity beyond 31.0w/m~2 , the output of anthocyanin increased insignificantly. 50ml of Roselle cells culture under 31.0w/m~2for 18days gave out 21.6mg of anthocyanin, and the pigment content in cell was 30.17mg/gWdc . Through the spectrum of visible light, blue light displayed the most significant enhancement on anthocyanin synthesis in Roselle cells, the red was least. Other monochromic lights with their wavelengths approaching that of the blue showed more positive effects. The cell anthocyanin content and the total anthocyannin output in result culture under blue light were 21.31 w/gwdc and 8.97mg, and those under the red were 1.92mg/gwdc and 0.84mg,respectly.Addition of riboflavin or β -caratene into culture didnot enhance anthocyanin synthesis by Roselle cell. KI as riboflavin activating state inhabitor reduced anthocyanin yield.Addition of Norflurazon, the inhabitor of carateniods synthesis, did not affect anthocyanin synthesis in Roselle cell. All those indicated that it was internal-produced riboflavin, not caratenoids.that might be the light receptor which was responsible for light absorbance and mediation involving in anthocyanin synthesis.Although Roselle cell cultured in darkness did not produce anthocyanin, the cell still had the potenty. The lagged irradiation was capable of inducing anthocyanin production in Roselle cell which was precultured in darkness. The output of anthocyanin in Roselle cell suspension that cultured in darkness for not longer than 8days and in the lagged irradiation for not shorter than 8days, was comparable with that under continous irradiation from beginning. Addition of fresh media or L-Phe enhanced the induction of anthocyanin production by light irradiation,from which a 2-stage culture of Roselle cell for anthocyanin production was suggested.Light irradiation also regulated Roselle cell PAL and total flavones synthesis,...