Does competition stress decrease allelopathic potential?

Annabelle Rivoal (1) , Catherine Fernandez (1) , Stephane Greff (1) , Nicolas Montès (1) , Bruno Vila (1)

1 IMEP - Institut Méditerranéen d'Ecologie et de Paléoécologie

In natural communities, plants compete in different ways, among them chemical interactions in the form of allelopathy. Whereas the effects of abiotic stresses (temperature, light, nutrients, etc.) on the production of allelochemicals are well known, only few studies deal with the impact of the stress induced by competition. When they do so, these studies are done under experimental conditions. The aim of this study is to evaluate the effect of intra-specific competition on the production of allelochemicals and biomass of Pinus halepensis Mill. in a natural forest using three levels of density. Phenolics and aliphatic acids were extracted from pine needles, analysed and quantified by GC-MS. Trunks, branches, needles and necromass were measured. We observed an increase in alle-lochemical content at low or medium level of competition and a decrease at high competition level. Moreover trees in competition allocate proportionally more biomass to the trunk and less to foliage and branches. This study provides evidence of substantial changes in allocation between the primary and the secondary metabolism.

Mots clés: Pinus halepensis; Competition; Stress; Allelopathy; Phenolics; Biomass; Allocation

Domaines: Biodiversité et Ecologie; Botanique

Annabelle Rivoal, Catherine Fernandez, Stephane Greff, Nicolas Montès, Bruno Vila. Does competition stress decrease allelopathic potential?. Biochemical Systematics and Ecology, 2011, 39 (4-6), pp.401-407. ⟨10.1016/j.bse.2011.05.017⟩. ⟨hal-01764833⟩