Biosynthesis Of Heat Shock Proteins (HSPs) Of Germinating Rice (Oryza Sativa L.) Embryos And Seedlings In Relation To Resistance To Chilling Injury

Rice(Oryza sativa L. cv. Qiyinzhan) seeds and seedlings were chosen as materials in this thesis to study the induced expression of heat shock proteins at various heat shock temperature and at different length of heat shock time. Protein metabolism of rice embryos during imbibition and effect of heat shock on it were also investigated. Meanwhile, the relationship between the effect of heat shock on the resistance of rice seedlings to chilling injury and protein metabolism and peroxidation of cell membrance lipids were also studied.It was found that the synthesis of most normal proteins of rice seedlings were repressed at non-lethal high temperatures and heat shock proteins were induced. Induced synthesis of heat shock proteins were different at different heat shock temperature. Specific proteins were labelled when rice seedlings were exposed to ³⁵S-Met at different heat shock temperature. Synthesis of normal proteins were inhibited at 37℃ for 4 h, but only HSP64 kD was induced at this temperature. Synthesis of maximum HSPs occurred at 40 ℃ to 43 ℃ . The nine heat shock proteins, corresponded to molecular weights of 78, 70, 64, 60, 46, 38, 24, 17 and 16 kD, were induced at 40 ℃ and 43 ℃. But only 70 kD HSP synthesized at 47 ℃, other HSPs were inhibited at this temperature. Bip and Ubi of rice seedlings were constitutively expressed,Treatment of 40 ℃ and 43 ℃ for 4 h may enhance their synthesis.³⁵S-Met total uptake of rice seedlings at various period was different. The time of maximum ³⁵S-Met uptake was 0-4.5 hours. From 0 to 12 hours after heat shock at 43 ℃, about twenty HSPs were induced respectively, low...