Allelopathic potential in the laurel forest of Tenerife, Canary Islands

Abstract: Laboratory and field experiments were conducted in order to assess the allelopathic potential of a laurel forest of Tenerife, Canary Islands. Decomposing litter and leaching from leaves or other plant parts can have inhibitory effects on seed germination and seedling growth. Two native species to the laurel forest were selected to test for allelopathic effects, Laurus azorica and Persea indica, since results from former studies have shown toxicity against other organisms. The target species were two annual bioassay species, Lepidium sativum L. (cress) and Lactuca sativa L. (lettuce). Both leaves from L. azorica and fruits of P. indica were shown to negatively affect germination and seedling development in Petri dishes as well as in sowing experiments. Samples from the forest floor were also influencing seedling growth of the bioassay species, although somewhat contradictory, in the laboratory experiments. From the field experiments another factor possibly influencing seedling survival was detected, the slug Plutonia lamarcki. These two factors, allelopathy and slug predation, could together have great influence in shaping structure and composition of this forest type.