Titre du document / Document title

Cassowary frugivory, seed defleshing and fruit fly infestation influence the transition from seed to seedling in the rare Australian rainforest tree,Ryparosa sp. nov. 1 (Achariaceae)

Auteur(s) / Author(s)

WEBHER Bruce L. ; WOODROW Ian E. ;

Résumé / Abstract

The rare Australian rainforest tree Ryparosa sp. nov. 1 aff. javanica (sensu Webber & Curtis, BW-017; Achariaceae) has large fleshy fruits that undergo a distinctive colour change during ripening. Fruit seem highly suitedto frugivore interactions with large ground-dwelling avian or marsupial frugivores, a role primarily filled by the endangered cassowary. We found that fruits had chemical defence traits that closely paralleled morphological ripening signals. Young fruit seeds had amongst the highest concentrations of plant tissue cyanogens ever recorded (some in excess of 12 mg g_-1 dw), yet the flesh of ripe fruits had negligible cyanogen defence. A seed treatment trial found that cassowary gut passage significantly improved germination from 4% to 92%, and we were not able to replicate this result with simulated treatments. While high levels of fruit fly larval infestation accounted for reduced seed viability, this predation was apparently reduced by cassowary gut passage. Post-germination seedling traits such as haustorial cryptocotylar cotyledons and epigeal germination may increase the chance of survival for establishing seedlings. We conclude that the range of traits seen in Ryparosa recruitment is particularly suited to interactions with frugivores and survival in a rainforest ecosystem.

Revue / Journal Title

Functional plant biology   ISSN 1445-4408 

Source / Source

2004, vol. 31, n^o5, pp. 505-516 [12 page(s) (article)]

Langue / Language

Anglais

Editeur / Publisher

Commonwealth Scientific and Industrial Research Organization, Collingwood, AUSTRALIE  (2002) (Revue)

Localisation / Location

INIST-CNRS, Cote INIST : 16620, 35400011061109.0110