Activation of Chlororespiration Increases Chlorophyll Fluorescence Yield in Chlorella Adapted to Darkness at High Temperature

摘要

A tenfold increase in Chlororespiration during dark incubation of Chlorella perynoidosa Chick CALU-175 at high temperature doubled the initial chlorophyll fluorescence yield (F_0). The presence of iodac-etamide or unmetabolizable glucose analog 2-deoxy-D-glucose prevented increase in both Chlororespiration and F_0 yield. The rates of Chlororespiration and F_0 yield growth demonstrated a similar pattern of temperature dependence. Inhibition of electron transport between Q_A and plastoquinone with diuron prevented increase in F_0 during dark incubation of the cells at high temperature. Apparently, a pool of plastoquinone was restored in the chlororespiratory chain during the dark incubation at 37.5-41℃, and plastoquinone exchanged electrons with Q_A. This is the cause of Q_A reduction and subsequent increase in F_0 yield.