The Role of Phytohormones in the Induction of Somatic Embryogenesis in <i>Pinus sibirica</i> and <i>Larix sibirica</i>

Abstract

The contents of auxin (indole-3-acetic acid, IAA), cytokinins, and abscisic acid (ABA) were determined in explants (megagametophyte and embryo), proliferating embryonal-suspensor mass (ESM), and non-embryogenic callus of Pinus sibirica and Larix sibirica. Furthermore, the localization of hormones in the cells was studied with immunohistochemical analysis. It was shown that the formation of embryogenic cultures in both species is associated with the content of phytohormones and their localization in cells. In L. sibirica the content of IAA in ESM was about 100 times higher than in non-embryogenic calli. At the same time, a low ABA content was characteristic of embryogenic cultures. Non-embryogenic callus contains an increased content of cytokinins and ABA. The transition of somatic cells to the path of embryogenic development is characterized by elongation of cells, their asymmetric division, and localization of IAA at one of the ends of elongated cells. Nonembryogenic callus consisted of isodiametric, actively dividing cells.

Effects of plant growth regulators and sucrose on proliferation and quality of embryogenic tissue in Picea pungens

“…Plant growth regulators (PGRs) play an important role in different species during the entire process of somatic embryogenesis 25 – 28 , such as ET induction ( Phoenix dactylifera ), ET proliferation ( Pinus sibirica and Larix sibirica ) and SE development/maturation ( Medicago sativa ) 24 , 29 , 30 . Therefore, it is crucial to gain insight into the potential effects of exogenously-applied PGRs on somatic embryogenesis.…”

Collectible Cell Lines of Larix sibirica Obtained by Somatic Embryogenesis and Their Ability to Regenerate

“…Initiation of an embryogenic culture (EC) in Larix sibirica begins with polarization, elongation of somatic cells, and localization of IAA at one end of an elongated cell [16]. Elongated cells divide asymmetrically to form a small embryonic cell (the initials) and an elongated tube cell.…”

“…A globule of a somatic embryo is formed from the embryonic cell. From the basal cells of the globule, suspensor tube cells are formed [16]. Globular embryos always have a clear polarization: the globule occupies the apical end, and the suspensor adjoins the basal part of the globule.…”

“…Currently, somatic embryogenesis is intensively investigated. Certain factual data have been accumulated on the study of morphological, physiological-biochemical, histological, and molecular genetic features of somatic embryo formation in gymnosperms [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. The use of somatic embryogenesis technology in combination with genomic selection and cryopreservation is the basis for multi-variety plantation reforestation (Multi-Varietal Forestry program, MVF) [23,24], aimed at growing economically valuable genetically tested clones and elite genotypes [23,25].…”

Pinus Sylvestris L. Mature Seeds Megamethophytes Cultured in Vitro. Influence of the Genotype and the Growth Regulators Content in Nutrient Medium on the Initiation of Callus Formation

“…It can also be assumed that the ability to form callus depends on the endogenous growth regulators content in explants (Vasil 1988). However, at the moment, there is not enough information on the mutual effect of endogenous and exogenous concentrations of growth stimulators on the initiation of somatic embryogenesis in conifers (Hmara 2015, Tretyakova et al 2021.…”