Subsurface aeration of tidal wetland soils: Root-system structure and aerenchyma connectivity in Spartina (Poaceae)

Root-aerenchyma in wetland plants facilitate transport of oxygen from aboveground sources (atmosphere and photosynthesis) to belowground roots rhizomes, where can leak out oxygenate the otherwise anoxic soils. In salt marshes, soil oxygenation capacity varies among different Spartina-taxa, but little is known about structural pattern connectivity root-aerenchyma that facilitates this gas transport. Both environmental conditions ploidy level play a role for root-system morphology. Root-system morphology polyploid Spartina-taxa was studied, quantifying root-tissue volume hexaploid Spartina alterniflora, maritima, × townsendii as well dodecaploid anglica habitats. Computed tomography (CT)-scan image analysis applied quantify aerenchyma, determine structure (ratio aerenchyma volumes) connectivity. On average, Spartina-roots accounted 12% (v/v) 1% pioneer marsh. About 90% all were associated with aerenchyma. structures S. differed showed clear responses habitat conditions, such flooding regime redox potential. The development large well-connected fragments specifically shown minor extend maritima. Aerenchyma alterniflora consisted only smaller fragments. Spartina-dominated tidal marsh soils show high atmosphere via root-aerenchyma. comes along