When the sugar concentration in the medium of Spathiphyllum is increased from 3 to 6% , higher concentrations of sucrose and starch are found in the leaves at the end of the in vitro period. During the first week after transfer to the greenhouse, the sucrose reserves are consumed by the plants to overcome the initial stress period (Fig 1).

In rose large deposits of starch (similar to those of greenhouse grown plants) were found in the chloroplasts of stage 3a shootlets developed in a culture medium with 5% sucrose. The dimension of the starch granules increased with increasing sugar concentration of the culture medium (Fig 2). It is assumed that this starch was used as a nutrient reserve by the in vitro shootlets, and so favoured rooting and growth during acclimatization in the greenhouse.