Root structure and biomass partitioning in tilted plants from twisted- and straight-6 stemmed populations of Pinus pinaster Ait.

Garrido, Fermín; San Martín, Roberto; Lario, Francisco José; Sierra-de-Grado, Rosario (2015) - Root structure and biomass partitioning in tilted plants from twisted- and straight-6 stemmed populations of Pinus pinaster Ait. - Trees

Pinus pinaster Ait. has a tendency to exhibit stem flexuosity that negatively affects the quality of its wood 13 and its productivity. There is a wide geographical variability in this trait, and there is evidence of genetic 14 control. We hypothesized that root structure and biomass allocation adjustments in response to a given 15 mechanical stress might differ among populations of P. pinaster and might be related to the typical 16 straightness of the stems of a given population. We analyzed root structure and biomass allocation in a 17 provenance test in which plants were artificially tilted at 45º and naturally exposed to wind. Ten 18 provenances were tested: five with typically straight-stemmed plants and five with twisted-stemmed 19 plants. The wind affected the taper and the development of thickenings in the windward second-order 20 roots, although the winds experienced were generally light. The straight-stemmed populations exhibited 21 greater variability in the studied traits than the twisted-stemmed populations. This variability may reflect 22 higher root responsiveness as well as various strategies to address mechanical stresses. Three possible 23 additional distinguishing characteristics of various straight-stemmed populations are proposed: a) greater 24 allocation of biomass to the stem compared with the branches, b) development of a thick, cylindrical taproot and tapered lateral roots and c) strengthening of second-order roots with local thickening in the 26 sectors of the root under tension.

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SI

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Artículos

Volumen: 

29, 3, pp 759-774