ABIOTIC STRESS EVOKED BY CRYOGENIC TREATMENT AND ITS IMPACT ON SECONDARY METABOLITE SYNTHESIS IN MEDICINAL PLANTS: HYPERICUM SPP. AS AN EXAMPLE

摘要

Prior to, during and post cryopreservation plant cells undergo a series of abiotic stresess as a consequence of explants isolation, precryogenic, cryogenic and postcryogenic treatments. These stresses comprise a break of integrity of a plant and correlation relationships within a plant, wounding caused by mechanical damage, decreasing of the temperature followed by dehydration and oxidative stress as a consequence of an increased production of reactive oxygen species. All these factors should be taken into account in postcryogenic assessments of plants regenerated from cryopreserved cells. In cryopreservation of medicinal plants abiotic stress may have a beneficial influence as an elicitor of secondary metabolite synthesis. In the present study some of these aspects are demonstrated on an example of medicinal plant species, Hypericum perforatum L. (Hypericaceae) as a model for the genus Hypericum which contains some unique secondary metabolites especially hypericins and hyperforins with anticancer and other pharmacodynamic activities.