Figure 2.

RNA-blot analyses of the L/D cycling expression pattern for six Hsp70s, PDI, cab, and rbcS in spinach leaf tissue. The expression of hsc70-1 (A; cytosol), hsc70-3 (B; cytosol), hsc70-12 (C; cytosol), hsc70-2 (D; ER), hsc70-9 (E; chloroplast), hsc70-10 (F; mitochondria), PDI (G; ER), cab (H; chloroplast), and rbcS (I; chloroplast) genes in response to one (a), two (b), or three (c) L/D cycles in a single 24-h period is shown. Plants were grown at 20°C in a controlled environment cabinet and entrained with a 12-h/12-h L/D photoperiod (1 cycle, “a” column) or were transferred to a 6-h/6-h L/D photoperiod (2 cycles, “b” column) or to a 4-h/4-h L/D photoperiod (3 cycles, “c” column). Each cycling experiment was repeated two or three times with similar results. One representative autoradiogram is shown here. Time is expressed on a 24-h basis. White and black bars and unshaded and shaded areas indicate light and dark phases, respectively. The plots are the ratio of autoradiographic band density/rRNA gel band density, to normalize loading differences.