Abstract: The effects of NaC1, PEG and exogenous ABA on the expression of the heat shock protein-Hpc60 from pea ( Pisum sativum L. ) were investigated. The results showed that PEG elevated the quantity of this heat-shock protein, much similar to heat-shock stress. Although NaC1 was able to reduce water potential at the same extent with or even higher than PEG, but it did not increase the level of this protein. This phenomenon was closely correlated with the variations of cytoplasmic ion levels. The authors postulated that NaC1 treatment caused the influx of Na + , thus disrupted the ion homeostasis, whereas PEG treatment did not. So a rather stable Na+/K+ ratio was sustained in the plant cell treated with PEG, which might be prerequisite for the induction of Hpc60. In addition, exogenous ABA was employed in the authors' experiment which showed no influence on the synthesis of this heat-shock protein.

Key words: Pea, Heat-shock protein, PEG, NaC1