However, leaf explants of Crepis novoana showed better response when placed with abaxial surface in contact with the media ( Corral et al., 2011). The influence of abaxial or adaxial orientation of leaf explants on plant regeneration in culture may result from cellular organization, degree of compactness, and structure and number of stomata which can influence uptake and transport of nutrients and growth regulators as well as degree of exposure to light.