Histological observation of changes in leaf structure during successive micropropagation stages in Aralia elata and Phellodendron amurense

Abstract

The micropropagation protocols for Aralia elata and Phellodendron amurense were established. The survival rates in the acclimatization process between the two species were found to be greatly different. To find the reasons for this difference, the morphological and histological changes in the leaf during successive micropropagation stages in in vitro-derived plantlets of A. elata and P. amurense were compared. Significant differences in mesophyll development in differentiation as well as vascular system development were found during the root induction stages. Such different leaf structures may be responsible for the survival rate through the acclimatization process. These results suggested that changes in leaf structure from in vitro to ex vitro plants are important for histological development, rendering them appropriate for in vitro hardening, which begins at the root elongation stage.