MECHANISM OF PROTECTIVE ACTION OF PLASMOLYSING SUCROSE SOLUTIONS DURING FREEZING OF WHEAT CELL-SUSPENSION

The protective action of plasmolyzing solutions of sucrose in the proc ess of freezing/thawing of cells of wheat suspension culture (Triticum timopheevi Zhuk.) was determined from escape of ions into the medium and chang in the ability of cells to reduce tetrazolium chloride. Both methods indicate that sucrose solutions protect cell suspension durin g freezing, but exert almost no protective action during thawing. It m ay be hypothesized on this basis that injuries to cells occur for the most part during freezing. Since the first of the methods used to dete rmine viability mainly estimates the extent of damage to the plasmalem ma, while the second appraises damage to mitochondria, it follows from the obtained results that sucrose protects different structures of pr otoplasts at the same time. Based on weak deformations of the plasmale mma and tonoplast, a possible mechanism of the protective action exert ed by sucrose solution during freezing of cells of wheat suspension cu lture is discussed in the work.