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

Abstract

Euterpe edulis Martius, commonly known as juçara, 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 µM picloram (PIC). After induction, the explants were transferred to maturation medium supplemented with 1-naphthaleneacetic acid (0.53 µM) and 2-isopentenyladenine (12.3 µM) and two maturation times (30 and 60 days) were evaluated. After 60 days of induction, proembryos appeared asynchronously directly from the stem segments. 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 µM 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.