Exogenously applied 24-epi brassinolide reduces lignification and alters cell wall carbohydrate biosynthesis in the secondary xylem of Liriodendron tulipifera

Hyunjung Jin, Jihye Do, Soo Jeong Shin, Joon Weon Choi, Young Im Choi, Wook Kim, Mi Kwon

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)


The roles of brassinosteroids (BRs) in vasculature development have been implicated based on an analysis of Arabidopsis BR mutants and suspension cells of Zinnia elegans. However, the effects of BRs in vascular development of a woody species have not been demonstrated. In this study, 24-epi brassinolide (BL) was applied to the vascular cambium of a vertical stem of a 2-year-old Liriodendron, and the resulting chemical and anatomical phenotypes were characterized to uncover the roles of BRs in secondary xylem formation of a woody species. The growth in xylary cells was clearly promoted when treated with BL. Statistical analysis indicated that the length of both types of xylary cells (fiber and vessel elements) increased significantly after BL application. Histochemical analysis demonstrated that BL-induced growth promotion involved the acceleration of cell division and cell elongation. Histochemical and expression analysis of several lignin biosynthetic genes indicated that most genes in the phenylpropanoid pathway were significantly down-regulated in BL-treated stems compared to that in control stems. Chemical analysis of secondary xylem demonstrated that BL treatment induced significant modification in the cell wall carbohydrates, including biosynthesis of hemicellulose and cellulose. Lignocellulose crystallinity decreased significantly, and the hemicellulose composition changed with significant increases in galactan and arabinan. Thus, BL has regulatory roles in the biosynthesis and modification of secondary cell wall components and cell wall assembly during secondary xylem development in woody plants.

Original languageEnglish
Pages (from-to)40-51
Number of pages12
Publication statusPublished - 2014 May

Bibliographical note

Funding Information:
We thank Dr. Insik Kim and Youngwook Kim at the Korea Forest Research Institute for providing Liriodendron seedlings for these experiments, and Dr. Ryo Funada at Tokyo University of Agriculture and Technology for providing a detailed hormone treatment protocol for tree stems. This study was supported by a Korea Research Foundation Grant ( 2012R1A1A3001418 ) funded by the Korean Government (MOEHRD, Basic Research Promotion Fund) and with financial support of ‘ Forest Science & Technology Projects ( S111212L18010 ) Grant provided by the Korea Forest Service .


  • Arabinan
  • Brassinolide (BL)
  • Cell wall
  • Cellulose
  • Crystallinity
  • Galactan
  • Hemicellulose
  • Lignin
  • Liriodendron tulipifera
  • Magnoliaceae
  • Pectin
  • Secondary xylem
  • Yellow poplar

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Plant Science
  • Horticulture


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