BHARATHAN, G1, T GOLIBER2, J-J CHEN2*, and N SINHA2. 1Ecology & Evolution, SUNY, Stony Brook, NY; 2Plant Biology, UCDavis, Davis, CA. - Simple leaves, complex leaves: which way?
The consequences of variation in leaf form (simple, complex) has long
intrigued plant physiologists and ecologists. Here, phylogenetic
methods (using recent molecular phylogenies of angiosperms) are used
to examine patterns in the direction of change. These analyses
suggest, commensurate with paleobotanical studies, that the ancestral
angiosperm had simple leaves. However, contrary to the general
(implicit) assumption, there is an overall trend of a lower frequency
of transitions from simple to complex (‘gains’) than from complex to
simple (‘losses’). This finding has wide-ranging molecular
developmental, physiological and ecological implications that are
briefly discussed.
Key words: development, evolution, leaf