Chemical differentiation between leaves of seedlings and spatially close adult trees from the tropical rainforest species Nectandra ambigens (Lauraceae): an alternative test of the Janzen-Connell model

Citation
Me. Sanchez-hidalgo et al., Chemical differentiation between leaves of seedlings and spatially close adult trees from the tropical rainforest species Nectandra ambigens (Lauraceae): an alternative test of the Janzen-Connell model, FUNCT ECOL, 13(5), 1999, pp. 725-732
Citations number
30
Categorie Soggetti
Environment/Ecology
Journal title
FUNCTIONAL ECOLOGY
ISSN journal
02698463 → ACNP
Volume
13
Issue
5
Year of publication
1999
Pages
725 - 732
Database
ISI
SICI code
0269-8463(199910)13:5<725:CDBLOS>2.0.ZU;2-K
Abstract
1. We tested the hypothesis of Langenheim and Stubblebine that differences in chemical composition between maternal trees and the seedlings under them arise from differential mortality; only seedlings different from the mothe r survive. Such mortality could explain at least some of the cases where se edlings accumulate under adult conspecifics, contrary to the extreme form o f the Janzen-Connell hypothesis. 2, We investigated Nectandra ambigens (Lauraceae), an upper-canopy tree at Los Tuxtlas tropical rain forest, Mexico, whose seedlings survive under the canopy of conspecific trees. We analysed chromatographic profiles of leaf terpenoids of 15 groups, each formed by an adult tree and its surrounding s eedlings. 3. We predicted that seedlings chemically similar to the adult would be abs ent under the tree canopy and that they would be present outside that canop y. We also predicted that younger seedlings would be more similar to the ad ult than the older ones. 4. Chemical similarity analyses showed that most seedlings were significant ly different from their closest adult and thus supported the Langenheim and Stubblebine hypothesis. However, we did not find chemical differentiation among seedlings regarding their age or their position inside or outside the tree canopy.