Our results suggested that the fully developed leaves of in vitro seedlings showed better regeneration capacity than the undeveloped ones, which is consistent with the findings of Lane et al. (1998), Rout (2002) and Mahalakshmi et al. (2006), whereas Perez-Tornero et al. (2000) and Gu and Zhang (2005) presented the opposite conclusion, implying that influence of explant age may be dependent upon other factors that are not deciphered as yet.