[Synthesis of heat shock proteins in developing maize embryo]

Labeling of protein in developing maize embryo with (35)S-Met showed that, the protein synthesis rate in heat shock (42 degrees C) was similar to that in the control (25 degrees C). Heat shock inhibited protein synthesis at 16 DAP, whereas it stimulated protein synthesis at 22 and 34 DAP. The pattern of SDS-PAGE showed that, a new set of heat shock proteins were induced after heat shock. At 16 DAP, heat shock induced 3 kinds of HSPs with molecular weight 86.4, 80.0 and 73.2 kD. And at 22 DAP, 7 kinds HSPs were induced with molecular weight 86.4, 80.0, 73.2, 24.4, 18.2, 16.8 and 13.6 kD. After 22 DAP, except 3 kinds of protein with molecular weight 73.2, 24.4 and 18.2 kD were induced turnover synthesis, other 4 kinds were increased by heat shock. The pattern of 2D-PAGE further suggested that, heat shock induced more than 20 kinds of HSPs at 22 and 28 DAP, especially the smHSP of 20-30 kD were more than 10 kinds. Western blot indicated that, BiP (HSP70) and PDI (HSP60) kept a high expression level during the embryo development, and failed to respond to heat shock.