Would you please introduce some good papers or useful techniques in controlling hyperhyricity?
Hello Saba,
More specific answer could have been given if you indicated the species and methods of culture leading to hyperhydricity. In general, this condition can be overcome by better ventilation of culture vessel, manipulation of solidifying media (even the concentration), 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.
Good luck!
Ranjith
Hello Saba,
More specific answer could have been given if you indicated the species and methods of culture leading to hyperhydricity. In general, this condition can be overcome by better ventilation of culture vessel, manipulation of solidifying media (even the concentration), 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.
Good luck!
Ranjith
It depends on the crop species, but also of the culture conditions. In Vitis I had hyperhydricity when I reduced the concentration of agar ( 3 months) and when there is too much variation in temperature between the dark phase and light phase (> 7 - 8 ° C). Pathirana's comments are very successful.
Hello Saba,
I agree with Pathirana's, Weiland and Ahuja comments and add:
Hyperhydricity could be also connected with application of too high level of cytokinine (especially BA) and sugars, both could cause cummulation of starch in cells - similar way as obesity at people :). You can try slow down metabolism - it could help. Good luck! Helena
HYperhydricity is an indicator that the conditions in culture are not suited to growth of the propagule. Water is being retained rather than flowing through the plantlet. Modify the media or growth room conditions to move water through the plantlet.
adjust the pH to 5.8, and correctly use the amount of agar at the time of preparation.
hi saba.
i think this condition related to
1- medium pH: specially low pH (lower than 4.5)
2- extra of ammonium in medium
3- deficiency of agar
good luck
hey Saba,
covering the culture vessel with para or clling film also reduces vitrification.
Hello Saba,Try increasing sugar level
Try increasing sugar level upto 4% in multiplication stage and 5% in rooting stage. We have got good results doing that. Even survival in acclimatization increased. Some were 100%.The below reference indicates some reasons. However, they do not tell that sugar prevents it. But with my experience 4-5 % sugar levels work really well.
Flooding of the apoplast is a key factor in the development of hyperhydricity
Niels van den Dries, 1 Sergio Giannì, 2 Anna Czerednik, 3 Frans A. Krens, 1 and Geert-Jan M. de Klerk 1 ,*
Author information ► Copyright and License information ►
This article has been corrected. See J Exp Bot. 2015 February; 66(3): 1041
Beside lowering nitrate concentration. Reduce Ethylene accumulation in vessels by better vents /closures for good air circulation.
Hello Saba
I totally agree with Pathirana and other researchers. You can also use 1.8 mM to 3.6 mM of Potassium Silicate in your media along with other methods to overcome hyperhydricity.
Reduce ammonium nitrate content in medium
Or
Increase agar concentration to solidify
Hyperhydricity can also be controlled by bottom cooling, which allows water to condense on the medium, the use of cytokinin-meta-topolin (6-(3-Hydroxybenzylamino)purine), the combination of lower cytokinin and ammonium nitrate in the medium, use of nitrate or glutamine as the sole nitrogen source and decreasing the
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