Comparative leaf anatomy of long pepper (Piper hispidinervum C. DC.) and spiked pepper (Piper aduncum L.) cultured in vitro, ex vitro and in vivo

Piper hispidinervum and Piper aduncum contain the secondary metabolites safrole and dilapiol, and there is commercial interest in their essential oils. The study aimed to compare anatomical aspects related to physiological responses of leaves from P. hispidinervum and P. aduncum propagated in vitro, in vivo and during acclimatization. Paradermal sections and cross-sections of leaves from in vitro, ex vitro and in vivo culture, were obtained for the measurement of anatomical structures using a light microscope. The thickness of the epidermis and hypodermis of P. hispidinervum and P. aduncum underwent changes in the transition from in vitro to ex vitro. Mesophyll tissues and stomatal pore opening of both species were inluenced by the environment in vitro. Different cultivation environments promote the plasticity of the cellular structures of the leaf blade and underlie the success of micropropagation of both species.