Challenges and insights in the acclimatization step of micropropagated woody plants

Abstract Acclimatization is the last step of plants in vitro propagation while it comes to alter the environment conditions from tailor for plant requirements, sterile laboratory to external ex vitro conditions. Consequently, during acclimatization it may reach to plants mortality due to abiotic and biotic stresses occurring in external environment (high temperature, light intensity, low air relative humidity and the presence of microorganisms and pathogens in soil). Micropropagated plants develop alter organs on morphological, anatomical or biochemical levels which must be correct during acclimatization to improve adaptation of plants to ex vitro conditions. Therefore, there is a need to create acclimatization protocols to improve the effectiveness of this vegetative propagation method. So far there were formulated facilities as pre-acclimation, in vitro acclimatization, water cultures, CO 2 enrichment, application of biostimulators and plant growth regulators. In following research we focused on describing previous achievements about the changes occurring in woody plants by micropropagation and summary of achievements in acclimatization of micropropagated woody plants. This article summary the current state of knowledge on acclimatization for various range of woody species by anatomical, physiological and biochemical levels. There are described ways to increase the survival of acclimatized plants and minimize acclimatization stress it also collects substances used so far to enhance plant growth during acclimatization.