SANCHEZ-GALLEN, IRENE & JAVIER F. ALVAREZ-SANCHEZ.
Universidad Nacional Autonoma de Mexico ; Mexico,DF.
Seedling establishment is a crucial step in plants life history
and is determined by several environmental conditions, such as resources availability
and biotic associations. The main goal of this study was to evaluate the role
of AM fungi on seedling growth and survivorship of tropical tree species under
different microenvironmental conditions. We designed a multifactorial
experiment with seedlings of Stemmadenia donnell-smithii, Poulsenia
armata and Nectandra ambigens (pioneer and nomad tree species,
respectively). Three factors with two levels (presence and absence) were
applied: mycorrhizae, light and nutrients. Data were analyzed by ANOVA's tests.
Light was the factor that explained most of all significant differences between
treatments in Stemmadenia and Poulsenia. Stemmadenia 's
mycorrhizal responsiveness was negative and for some variables, mycorrhizae
presence implied a great ecological cost. Poulsenia presented low
mycorrhizal responsiveness values. Also, for Nectandra, light was the
main factor that explicated significant differences, but in the last months,
interaction between light and mycorrhization was the relevant one. Mycorrhizal
responsiveness did not show any pattern. Survivorship was very low for shadow
treatments except for Nectandra. Mycorrhizae role on tropical natural
plant communities is still obscure probably, its presence is more related to
improve competition plant abilities, pathogens resistance, leaves survivorship
than to typical growth variables. Also, it is important to look at interactions
among factors instead of considering them as isolated variables.
Poster PRESENTATION