Decreased morphogenetic potential in peach palm stem-like cells in long-term in vitro conditions

Peach palm (Bactris gasipaes Kunth) has been micropropagated from pre-procambial cells that provide stem-like cell niches, (i.e., pre-procambial cells), multipotent, pluripotent and totipotent for direct vascularization, adventitious buds and somatic embryogenesis, respectively. The direct induction of adventitious buds and somatic embryogenesis reduces the frequency of mutations when compared to indirect morphogenesis. Long-term in vitro cultivation of perennial species such as peach palm cause the clones to age and deteriorate; however, the consequences for morphogenesis potential are not fully clear. The morphogenic potential of peach palm clones established and in vitro cultivated for 8 years (regeneration of adventitious buds without callus formation) was investigated in leaves, roots and stem bases using histological and histochemical analyses. Data from long-term cultures (8-years-old) was compared to data from short-term cultures (1-year-old). Morphogenic pathways monitoring for direct induction of somatic embryos and adventitious buds revealed a strong morphogenic reduction potential in the pre-procambial cells, parenchyma cells in the proximal region of stem bases, and external cells of leaf sheaths. Initial cells of shoot apical meristems and pre-procambial cells commit cell reprogramming to the undifferentiated state and subsequent acquisition of cellular competence. These results are applicable in the micropropagation of peach palm, with consideration to obtaining clones and their long-term in vitro culture.