Thank you Gokul I have switched to microagar instead of phytagel I will try normal conc of 8g/l if I have troubles I will increase to 10. Do you agree?

Ciao Pasquale,

We did not have such a problem with transformed tomato plants (Published in: Brummell et al. Biofortification of Tomato Fruit with the Anticancer Compound Methylselenocysteine Using a Selenocysteine Methyltransferase from a Selenium Hyperaccumulator, J Agric. and Food Chemistry, 2011 59: 10987-20994) and we used agar as the solidifying agent. Other precautions you can take include: better ventilation of culture vessel, more frequent subculture and adding anti hyperhydricity agents such as EM2, gelling agents conyaining pectin or certain polysaccharides extracted from seaweeds. If you are using rich media, try lowering the concentration of major salts (e.g.half MS macro), try replacing ammonium with nitrate. I have noticed that water condensation on culture vessel also contributes to this condition, so vessels that allow better ventilation will help. If your rack gets heated at the bottom (often this happens when there is another set of lights below), you should raise the culture vessel, not allowing it to touch the surface by using a wire mesh for example. If you can maintain the bottom of vessel colder than top, water will condense on the agar, thus reducing hyperhydricity. By the way, science community now use the term hyperhydricity as against vitrification as the latter is now more and more used in cryopreservation, to supercool cytoplasm without ice crystal formation.

Grazie,

Ranjith

Thank you very much Gokul!Your suggestion is clear and competent. Any suggestion for stimulate rooting?