From Zygotic to Somatic Embryogenesis: A Difficult Task for Pinus Sylvestris L. Biotechnological Propagation

Abstract

Abstract Data on the development of the Pinus sylvestris zygotic embryos collected from trees of different ages, growing in the territory of southern Karelia (the 1st order Petrozavodsk Seed Orchard, progeny trial in the Manga village, Petrozavodsk Park) are presented. It was found that fertilization and further formation of zygotic embryos occurred faster in trees that grew in the park, which is possibly due to the microclimatic conditions formed in the urban environment. The in vitro culturing of 1022 megagametophytes containing immature embryos on DCR nutrient medium has showed that explants collected from 40 years old clones of plus trees on the Petrozavodsk SO extruded (8.06 ± 1.33%) and formed callus (0.65 ± 0.32%) more actively, than explants from younger trees (10–20 years old) both from the park and the progeny trial. It was revealed that megagametophytes containing zygotic embryos at the stage of cleavage polyembryony were the most responsive explants for the somatic embryogenesis initiation. Nevertheless explants with zygotic embryos at globular and precotyledonary stages also formed callus. One of the reasons for the failure of P. sylvestris somatic embryogenesis initiation appeared to be the developmental pathology which led to absence of formed zygotic embryo within the megagametophyte.