Cytohistological Studies on the Callus Genesis and Meristematic Nodule Formation of Paeonia×lemoinei ‘Golden era’ Histology and Development Analysis of Meristematic Nodules from Cultured Pulsatilla koreana Morphological and Histological Examination of Meristematic Nodules from#br# Adventitious Root of Pulsatilla koreana Morphological and Histological Examination of Meristematic Nodules from#br# Adventitious Root of Pulsatilla koreana Meristematic Nodule: a Valuable Developmental Pathway for Plant Regeneration