Seasonal abscisic acid accumulation in stem cambial region of Pinus silvestris, and its contribution to the hypothesis of a late-wood control system in conifers
1980
Wodzicki, T.J. | Wodzicki, A.B. (University of Agriculture, Warsaw (Poland). Dept. of Plant Biology)
Gradual accumulation of natural inhibitor in tissues comprising the cambial zone and about 1 mm of the youngest phloem of the basal region of the Pinus silvestris stem during the season was detected by both extraction and diffusion methods followed by bioassays. The purified inhibitor was chromatographically identified as similar to abscisic acid. Taking into account earlier numerous results, the hypothesis is formulated that the seasonal accumulation of abscisic acid affects phenomena associated with auxin polar transport, so that autolytic breakdown of protoplasts, which terminates differentiation of tracheids in stem secondary xylem is delayed. This effect extends the maturation phase and results in formation of thick-walled tracheids, characteristic for the late-wood in conifers
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