Protocol to Test the Effect of Sorbitol in vitro on Hybrid Larch (Larix x eurolepis Henry) Emblings This protocol presents a method to test the effect of sorbitol in vitro on hybrid larch plants derived from somatic embryogenesis. We have tested four different media variants, one control variant without sorbitol and three variants of decreasing water potential corresponding to sorbitol concentrations in the culture medium of 4%, 10%, and 20%. We cultured two hybrid larch clones on these media during 35 days and assessed their vitality and weight growth after this time.