Cambial development and tracheid length of dwarf pines (Pinus densiflora and P. thunbergii)

Abstract

From a comparison of cambial cells and their derivatives between naturally occurring dwarf trees and normal ones, it was concluded that tracheids in the annual rings of dwarf trees are shorter, narrower and fewer than those of normal trees. The frequency of anticlinal division and loss of cambial initials is low during differentiation of xylem cells from cambial initials in dwarf pines. The length and intrusive growth of fusiform initials are slightly less than those of normal trees. Thus, it is concluded that the shortening of tracheids in dwarf trees is doe to the fact that cambial initials are themselves shortened arid that intrusive growth during differentiation of xylem mother cells has occurred.