Study of senescence in old cultures of the Bactris gasipaes Kunth in vitro

Abstract

The in vitro propagation is a technique that is used for the large-scale generation of stable genotypes that are free of disease. Satisfactory propagation has been obtained using Bactris gasipaes Kunth through the direct in vitro regeneration of adventitious buds and somatic embryos, which is likely because of the pluri—and totipotency of the preprocambial cells, which reduces the probability of genetic instability. The consequences of the prolonged period of in vitro cultivation of perennial species such as the peach palm are not clear, as well as the senescence process has only been investigated in species originating from callus structures. The senescence of peach palm clones established and cultivated in vitro for 8 years through direct morphogenic methods (in vitro regeneration of adventitious buds without callus formation) was investigated in the leaves, roots and stem bases using histological, histochemical and ultrastructural analyses, in addition to the TUNEL reaction, to detect programmed cell death. These data from old cultures (8 years cultured) were compared to similar data from plants of the same species that had been established and cultivated in vitro for 1 year (young cultures). These analyses demonstrated the existence of intensive programmed cell death in the various tissues of the old cultures. The in vitro cultivation of peach palm for long periods promoted generalized senescence and probable aging of clones.