title: The effects of localized heating and disbudding on cambial reactivation and formation of earlywood vessels in seedlings of the deciduous ring-porous hardwood, Quercus serrata.
abstract: OBJECTIVE
  The networks of vessel elements play a vital role in the transport of water from roots to leaves, and the continuous formation of earlywood vessels is crucial for the growth of ring-porous hardwoods. The differentiation of earlywood vessels is controlled by external and internal factors. The present study was designed to identify the limiting factors in the induction of cambial reactivation and the differentiation of earlywood vessels, using localized heating and disbudding of dormant stems of seedlings of a deciduous ring-porous hardwood, Quercus serrata.
  
  
  METHODS
  Localized heating was achieved by wrapping an electric heating ribbon around stems. Disbudding involved removal of all buds. Three treatments were initiated on 1 February 2012, namely heating, disbudding and a combination of heating and disbudding, with untreated dormant stems as controls. Cambial reactivation and differentiation of vessel elements were monitored by light and polarized-light microscopy, and the growth of buds was followed.
  
  
  RESULTS
  Cambial reactivation and differentiation of vessel elements occurred sooner in heated seedlings than in non-heated seedlings before bud break. The combination of heating and disbudding of seedlings also resulted in earlier cambial reactivation and differentiation of first vessel elements than in non-heated seedlings. A few narrow vessel elements were formed during heating after disbudding, while many large earlywood vessel elements were formed in heated seedlings with buds.
  
  
  CONCLUSIONS
  The results suggested that, in seedlings of the deciduous ring-porous hardwood Quercus serrata, elevated temperature was a direct trigger for cambial reactivation and differentiation of first vessel elements. Bud growth was not essential for cambial reactivation and differentiation of first vessel elements, but might be important for the continuous formation of wide vessel elements.
authors.affiliation: Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Kayo
authors.initials: K
authors.lastname: Kudo
authors.forename: Eri
authors.initials: E
authors.lastname: Nabeshima
authors.forename: Shahanara
authors.initials: S
authors.lastname: Begum
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Yamagishi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nakaba
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Oribe
authors.forename: Koh
authors.initials: K
authors.lastname: Yasue
authors.forename: Ryo
authors.initials: R
authors.lastname: Funada
mesh_terms: D006358:Hot Temperature; D029963:Quercus / Q000254:growth & development*
keywords: Cambial activity; Quercus serrata; deciduous ring-porous hardwoods; disbudding; formation of earlywood vessel; localized heating; oak