Original article

Journal of Wood Science

, Volume 58, Issue 5, pp 437-445

First online:

Accumulation of constitutive diterpenoids in the rhytidome and secondary phloem of the branch bark of Larix gmelinii var. japonica

  • Kazuto SekiAffiliated withForest Products Research Institute, Hokkaido Research Organization Email author 
  • , Ken OrihashiAffiliated withForest Products Research Institute, Hokkaido Research Organization
  • , Mayumi SatoAffiliated withForest Products Research Institute, Hokkaido Research Organization
  • , Masanori KishinoAffiliated withForest Products Research Institute, Hokkaido Research Organization
  • , Naoto SaitoAffiliated withForest Products Research Institute, Hokkaido Research Organization

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

The quantitative compositions of the major constitutive diterpenoids in the rhytidome and secondary phloem of the branch bark of Kuril larch (Larix gmelinii var. japonica) were investigated. The eight major diterpenoids were isolated from a diethyl ether extract of the branch bark of L. gmelinii var. japonica and identified as 13-epimanool (1), larixol (2), larixyl acetate (3), 13-epitorulosyl acetate (4), abietic acid (5), neoabietic acid (6), dehydroabietic acid (7), and isopimaric acid (8). The amount of each diterpenoid was subsequently quantified in both the rhytidome and secondary phloem. All of the diterpenoids were present in both bark tissues, but the amounts were significantly higher in the rhytidome than in the secondary phloem. Developed fusiform resin cavities containing oleoresins were commonly observed in dead secondary phloem captured into the rhytidome of a bark transverse section. The accumulation and distribution of these constitutive diterpenoids in the bark tissues can probably be attributed to terpenoid biosynthesis in the living secondary phloem and the rhytidome formation process. From the viewpoint of constitutive chemical defense in conifers, it is suggested that the tree body may be more effectively defended against natural enemies by the higher amount of diterpenoid amount in the outermost and dead bark tissue, the rhytidome, where the potentially poisonous and easily oxidizable diterpenoids can be safely and stably maintained.

Keywords

Constitutive terpenoids Rhytidome Secondary phloem Larix gmelinii var. japonica Plant chemical defense