title: Developmental plasticity of glandular trichomes into somatic embryogenesis in Tilia amurensis.
abstract: OBJECTIVE
  In Tilia amurensis, two types of trichomes (hairy and glandular) develop from epidermal surfaces of cotyledons and hypocotyls of zygotic embryos soon after germination. Here, it is demonstrated that glandular trichome initials develop directly into somatic embryos when treated in vitro with 2,4-dichlorophenoxyacetic acid (2,4-D).
  
  
  METHODS
  Zygotic embryos of Tilia amurensis were cultured on Murashige and Skoog medium with 3 % sucrose and various concentrations (0, 2.2, 4.4 and 8.8 microm) of 2,4-D. Morphological development of trichomes and somatic embryos was analysed by scanning electron microscope and light microscope after histological sectioning.
  
  
  RESULTS
  In zygotic embryos cultured on medium with 4.4 microM 2,4-D, formation of hairy trichomes was completely suppressed but formation of glandular trichome initials increased. That some filamentous trichome initials developed directly into somatic embryos was confirmed by histological and scanning electron microscope observation. When explants with different stages of trichome initials (two-, four- and eight-celled filamentous and fully mature trichomes) were temporally pre-treated with 4.4 microM 2,4-D for 24 h and transferred into hormone-free medium, two-celled and four-celled filamentous trichome initials were the effective stage of trichomes for somatic embryo induction.
  
  
  CONCLUSIONS
  It is suggested that early developing filamentous trichome initials have developmental plasticity and that with 2,4-D treatment these trichome initials develop directly into somatic embryos.
authors.affiliation: Division of Forest Resources, College of Forest and Environmental Sciences, Kangwon National University, Chunchon 200-701, Korea.
authors.forename: T D
authors.initials: TD
authors.lastname: Kim
authors.forename: B S
authors.initials: BS
authors.lastname: Lee
authors.forename: T S
authors.initials: TS
authors.lastname: Kim
authors.forename: Y E
authors.initials: YE
authors.lastname: Choi
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid; D018548:Cotyledon / Q000254:growth & development*; D046508:Culture Techniques; D047108:Embryonic Development / Q000502:physiology*; D018546:Hypocotyl / Q000254:growth & development*; D019441:Plant Epidermis / Q000254:growth & development*; D032384:Tilia / Q000196:embryology / Q000254:growth & development*
chemical_list: D015084:2,4-Dichlorophenoxyacetic Acid