Document: TJE-3-33-29

Root system topology and diameter distribution of species from habitats differing in inundation frequency.

BOUMA, T.J.* ¹, K.L.NIELSEN ², J.VAN HAL ¹ and B.KOUTSTAAL ¹

Netherlands Institute of Ecology, The Netherlands ¹
Danish Institute of Agricultural Sciences, Denmark ²

Abstract:
We studied trade-offs in root growth strategies on seven halophytic species that dominate contrasting elevations in the salt marsh. We expected that: 1) Dicots from the low marsh have herringbone-like roots versus more complex branched roots for dicots from higher elevations; 2) all grasses have herringbone roots, regardless of their elevation; and 3) the root diameter increases with link magnitude, especially for herringbone-shaped roots. With increasing elevation, the lengths of individual laterals of the Chenopodiaceae tended to increase, their branch density significantly, so that the relative length of the main root decreased. Although root branching became indeed somewhat more complex for species from higher elevations, all root systems remained close to herringbone structured. The Gramineae, too, showed a tendency to increased length of individual laterals with increasing elevation. Root topology was not related to the elevation and did not indicate a perfect herringbone structure for all grass species studied. Roots of 1st-order laterals were approximately 1/3 of the diameter of the main root; 2nd-order laterals were approximately 1/2 the diameter of the 1st-order laterals. These ratios warrant a good transport capacity between different orders of roots, and illustrate the value of the developmental segment ordering system.

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This abstract is being presented at: 3:30 PM in session:
ROOT PROCESSES