Movement of Injected Dyes in Gymnosperm Stems in Relation to Tracheid Alignment

The path of upward movement of acid fuchsin dye was traced in pole-size stems of Japanese larch ( Larix leptolepis Murr.), European larch ( Larix decidua Mill.), Lawson cypress ( Chamaecyparis lawsoniana (A. Murr. Parl.)), Sitka spruce (Picea sitchensis (Bong. Carr.)), Norway spruce ( Picea abies (L.) Karst.), and Scots pine ( Pinus sylvestris L.). In all of these species a marked, preponderantly clockwise spiral pattern of dye ascent was observed. In general the upward movement of the dye followed tracheid alignment, except at the sapwood-heartwood boundary. The characteristic patterns of dye movement indicated that spiral grain was much commoner than was straight grain among the pole-size gymnosperms investigated. Large differences in spiral grain were found among species, among trees within species, in different annual rings within trees, and at different stem heights. Patterns of dye uptake were influenced somewhat by the method of injection. Dye injections through tubes driven into the stem were found more suitable for determining tracheid arrangement than were injections through individual roots immersed in dye. Factors influencing spiral grain development and applications of the dye injection technique to spiral grain determination are discussed.