Soluble and Insoluble Protein Patterns during Induction of Freezing Tolerance in Black Locust Seedlings

Protein metabolism plays a major role in the development of freezing tolerance in plants. Soluble and insoluble protein concentrations were followed during induction of freezing tolerance in black locust (Robinia pseudoacacia L.) stem tissues. Soluble proteins were fractionated using two-dimensional polyacrylamide gel electrophoresis and examined for the presence of glycoprotein fractions. Soluble protein concentration remained relatively constant during early stages of induction of freezing tolerance but increased significantly during later stages, while insoluble protein concentration remained relatively constant throughout induction. A new soluble protein component appeared during later stages of induction and was identified as a glycoprotein. Some glycoproteins are known to have a high water-binding capacity, which could play a role in intracellular resistance to ice formation during development of freezing tolerance.