Seed cryopreservation without vitrification (PVS2) induces oxidative stimuli to promote endoreplication in red pitaya seedlings

Endoreplication is a process by which cells replicate their genomes without mitosis, resulting in an increase in nuclear DNA ploidy. This study is the first to report that oxidative stimuli from cryopreservation of seeds in liquid nitrogen induces endoreplication. We list evidence that the cryopreservation of red pitaya seeds (Hylocereus costaricensis) in liquid nitrogen for 30 and 60 days induced genome duplication stimuli via endoreplication. It was demonstrated that this conservation technique modulates the levels of hydrogen peroxide (H2O2) and antioxidant enzymes, triggering oxidative stimuli. The flow cytometry analysis of cladodes revealed different levels of ploidy between the tissues (mixoploidy) and that seedlings from the longest cryopreservation times of seeds showed higher percentages of octoploid nuclei when compared to the control treatment. The cryopreservation of seeds for 60 days also allowed increases of approximately 130 Oxidative signaling in seeds (induced by cryopreservation) triggers stimuli to promote endoreplication in pitaya seedlings, resulting increases in ploidy levels and in plant biomass.