Environ Exp Biol (2017) 15: 37–46

Micromorphological response towards altered environmental conditions in subsequent stages of in vitro propagation of Morinda coreia

Abstract

The foliar micromorphological alterations from in vitro to field environments of micropropagated plantlets of Morinda coreia Buch. and Ham. were compared as developmental changes across the culture conditions. There were gradual developmental responses in stomatal structures, vascular tissues (venation) and raphides towards the field environment. The leaves under in vitro environment were thin with poorly developed leaf characteristics; these were impaired through ex vitro rooting prior to field transplantation. In vitro leaves had lower vein islet density (8.6 ± 0.16) and vein terminations (0.0) and raphide density (8.0 ± 0.19) as compared to rooted and acclimatized leaves. The physiological and structural adaptations in terms of stomata development lead to effective regulation of transpiration. Improved vein density for proper translocation of nutrients was achieved during gradual acclimation. Development of crystals, raphides and trichomes in the field environment suggested improvement in defense mechanisms. The gradual changes in foliar micromorphological structures during subsequent stages were responsible for adaptability, leading to improved survival success of in vitro regenerated plantlets of M. coreia during their field trials.