Effects of sand deposition on the interaction between Ammophila arenaria, plant-parasitic nematodes, and pathogenic fungi

Abstract

Arnrnophila arenaria is a dominant sand-fixing plant species of the European coastal foredunes. It remains vigorous under regular burial conditions on seaward slopes, but starts to degenerate when sand accumulation diminishes. Several hypotheses have been put forward to explain this degeneration. In this study, we test the hypothesis that upward growth of plants following sand burial enables them to escape harmful soil organisms. Plants in a degenerating field stand of A. arenaria and potted plants grown in sterilized sand (outdoor pot experiment) were buried with sterilized or nonsterilized sand. Burial in both sterilized and nonsterilized sand resulted in stem elongation, increased numbers of living shoots, and increased shoot and root biomass. However, when plants were grown in and buried with sterilized sand, the numbers of shoots were significanlty higher than those buried with nonsterilized sand. The new root zone of buried plants was colonized by pathogenic soil organisms (nematodes and fungi) during the same growing season. It is concluded that by upward growth through pathogen-free sand, the plants benefit, at least temporarily, from escaping its pathogens and parasites.Rdsumd : L'Arnrnophila arenaria est une espkce de plante dominante capable de fixer les sables des dunes c8tikres frontales en europe. Elle demeure vigoureuse sous des conditions rCgulikres d'ensablement sur les pentes opposCes a la mer, mais commence 21 dtgCnCrer lorsque l'accumulation de sable diminue. Plusieurs hypothkses ont Ct C mises de I'avant pour expliquer cette dCgCnCrescence. Dans cette ttude, les auteurs Cvaluent l'hypothtse selon laquelle la croissance dressCe des plantes, suivant le recouvrement par le sable, rendrait ces plantes capables d'Cchapper aux organismes nuisibles du sol. Des plantes situCes dans une station en dtgtnCrescence de I'A. arenaria et des plantes produites en pot dans du sable stCrilisC (expCrience en pots a I'extCrieur) ont Ct C enterrCes avec du sable stCrilisC et du sable non-stCrilist. Dans les deux cas, l'enterrement avec du sable stCrilisC ou non-stCrilisC conduit a 1'Clongation des tiges, a I'augmentation du nombre des tiges vivantes ainsi que l'augmentation des biomasses des tiges et des racines. Cependant, lorsque les plantes poussent dans le sable stCrilisC et sont enterrCes avec du sable stCrilisC, les nombres de tiges sont significativement plus grands que chez les plantes enterrCes avec du sable non-stCrile. La nouvelle zone racinaire des plantes enterrCes est colonisCe avec des organismes tdaphiques pathogknes (nimatodes et champignons) au cours de la m&me saison de croissance. Les auteurs concluent qu'au moyen de la croissance dressCe a travers le sable sans pathogkne, la plante ont profitC, du moins temporairement, de I'Cloignement de ses pathogknes et parasites.

Development of a negative plant–soil feedback in the expansion zone of the clonal grass Ammophila arenaria following root formation and nematode colonization

“…Plants in the field must therefore be able to overcome the proposed negative feedback. The mass of shoots and below‐ground stems (rhizomes) were not determined, but previous studies have demonstrated a mass gain in these plant organs over the growing season (De Rooij‐Van der Goes et al . 1995b).…”

Vegetation and sedimentation on coastal foredunes

“…Conversely, the amount of deposition also affects the vitality of marram grass (De Rooij-Van Der Goes et al, 1995;Disraeli, 1984;Konlechner et al, 2013;Maun, 1998;Van der Putten and Peters, 1997). Marram grass requires a certain amount of burial for optimal growth.…”

Ecological effects of the non-native Pinus nigra on sand dune communities

“…In foredunes, both understory cover and light intensity were lower in P. nigra stands than in Populous deltoides stands (Figs. Alternatively, increased intensity of pathogens and decreased sand burial may limit the growth of the foredune grasses in stabilized sand in pine stands relative to the more dynamic Populus deltoides stands (de Rooij-van der Goes et al 1995 The wetpanne habitat provided an opportunity to compare the effects of the introduced pine with those of a native pine on abiotic and biotic components of the wetpanne. 5a), but species richness and solum thickness did not differ ( Fig.…”