IMPACT OF OSMOTIC POTENTIAL ON IN VITRO CULTURES OF APPLE

Reducing the concentration of nutrient salts and sugar in the media has been helpful for rooting apple shoots in tissue culture.
This change decreases nutrient and energy supply and reduces the osmolality of the media.
In order to study the relative importance of the osmotic effect, in vitro cultured apple shoots of two genotypes, the cultivar ‘Gala’ and the clonal rootstock ‘Mark’, were transferred to a range of media varying in osmolality by adding different amounts of mannitol.
Shoot growth and formation of roots were recorded on a weekly basis.
Measurements of osmotic potential of the media and different parts of the shoots were taken with a vapor pressure osmometer once a week.
Under the conditions of the present study the genotype was the most important factor for rooting.
With both genotypes, the highest percentage of root formation was observed in the basal medium, which also had the highest osmolality, and nutrient and energy supply.
Reductions in any of these factors resulted in improved shoot growth.

I International Symposium on In Vitro Culture and Horticultural Breeding

C. Lankes, R. H. Zimmerman

https://doi.org/10.17660/ActaHortic.1990.280.67