“…At present, the causes of physiological disorders associated with hyperhydration remain undiscovered, but, as confirmed by our observations, some authors point out that the concentration of carbohydrate and gelling agents, pH variations and water content in the medium can be possible factors that contribute to this process (Yao et al, 1996;Ueno et al, 1998). In spite of agar being considered an inert substance which would apparently exert no osmotic effect over the system (Kyte, 1987), a high concentration of agar in the medium leaves less water available for explants through the increase of the matrix potential (Pierik, 1990), thus reducing the hyperhydration risk of explants (Bhojwani and Razdan, 1996).…”