LAUSR

The development of methods for long-term storage of microalgae remains an important and complex problem, the solution of which is impossible without studying the processes occurring during dehydration and rehydration of vegetative cells. The study presents the results from the investigation of changes in the dimensional characteristics of cells and trichomes of spirulina Arthrospira (Spirulina) platensis (Nordstedt) Gomont after dehydration and during reactivation (in dynamics) as well as processes occurring in them during reactivation. Methods close to natural dehydration were selected. Morphometric measurements of cells and trichomes of spirulina in their native state and during dehydration and rehydration were performed. Dehydration of A. platensis was accompanied by statistically significant changes in the morphometric characteristics of cells. For all methods of dehydration (in a thermostat at 30 and 60°C and on silica gel in a desiccator at a room temperature of 20°C) a decrease in their size, as well as elongation and flattening, were noted. The thickness and volume of trichomes after dehydration were reduced by two times. All processes occurring during reactivation were traced in dynamics, from the moment of moistening to the appearance of young threads. A relatively rapid flooding of the dried cells and a gradual restoration of their morphometric characteristics was noted. Among the reactivating trichomes, those in which the separation into viable and irreversibly areas damaged was clearly visible were found. Differential staining of trichomes with methylene blue revealed cells with strong plasmolysis inside externally intact threads. Morphometric parameters of the spirulina cell were restored within 24 h. This fact indicates that, in dehydrated cultures after rehydration, a number of complex biochemical processes occur, due to which the initial physiological state of the cells is restored.