Cell reprogramming via direct somatic embryogenesis in an Atlantic Forest species vulnerable to extinction: Euterpe edulis stem segments induced with picloram

Key messageSomatic embryogenesis occurs directly and the polarity of the explants does not influence the number of somatic embryos generated. Euterpe edulis Martius, commonly known as jucara, has high economic value because its palm heart is considered a delicacy and its fruit, which is rich in antioxidants, is considered a super fruit. Because this endangered species can only be propagated via the seminiferous route, we aimed to analyze somatic embryogenesis of stem explants from E. edulis seedlings in response to their polarity and the type and concentration of growth regulators. Immature seeds were collected from a selected matrix in Pedra Menina (ES/MG, Brazil) and germinated in vitro. Six-month-old seedlings were segmented into four explants based on their polarity, and placed in culture medium supplemented with 50, 100, 150, 200, 250, 300, 450 or 600 mu M picloram (PIC). After induction, the explants were transferred to maturation medium supplemented with 1-naphthaleneacetic acid (0.53 mu M) and 2-isopentenyladenine (12.3 mu M) and two maturation times (30 and 60 days) were evaluated, subsequently, being transferred to MS medium without growth regulators, for embling conversion, and in substrate for acclimatization. After 60 days of induction, proembryos appeared asynchronously directly from the stem segments. The PIC concentrations of 150, 200 and 450 mu M resulted in more embryogenic centers in the apical growth region or stele, with a greater number of proembryos (12.75) at the 150 mu M concentration. Upon transfer to maturation medium, a large number of somatic embryos and masses were observed at both times. The polarity of the explants did not influence their embryogenic induction, and all four stem segments could be used for somatic embryogenesis following treatment with 150 mu M PIC. A large number of somatic embryos were generated during later stages of maturation. It is recommended to remove the explants from the maturation medium after 30 days to avoid oxidation. 20% of somatic embryos are converted into emblings and proceed to acclimatization.

Automated summary

Somatic embryogenesis of E. edulis stem explants is not affected by their polarity, and a concentration of 150 mu M PIC in the culture medium results in the highest number of embryos. After 30 days of maturation, the explants should be transferred to a different medium to avoid oxidation. Around 20% of somatic embryos successfully convert into plantlets and can be acclimatized.