The hyperhydricity, formerly called vitrification, is considered a physiological, biochemistry and morfologic disorder due to abnormal accumulation of water inside the cells and tissues. Plants grown in vitro are undoubtedly under continuous stress condition which results in metabolic changes characteristic of oxidative stress. Anatomically plants or shoots affected often become swollen, with pale green, translucent sheets, glass-like, low relative number of cells / cell area and hipolignification. Physiological changes occur in major metabolic pathways including photosynthesis, respiration and transpiration resulting in reduced efficiency of these metabolic pathways. Morphological, physiological and biochemical disorders are triggered by physical factors related to the environment of cultivation vessels and consistency of the culture medium or by chemical factors such as culture medium components, especially the growth regulators in high concentrations. The hyperhydricity occurs at various levels of severity, reaching result in irreversible loss of morphogenic capacity and the establishment of a state of neoplastic cells, however, in most cases hyperhydricity is considered reversible. This review focuses on the current knowledge about the phenomenon of hyperhydricity addressing morphological, physiological, biochemical, and reversibility of the process.
translucent shoots; culture condition; physiological disorders; in vitro culture problems; vitrification
