Ontogenetic Reaction Norms in Lobelia Siphilitica (Lobeliaceae): Response to Shading

摘要: Research on the genetics of development and reactions to environmental changes (phenotypic plasticity) is important understand evolution natural popu- lations, mostly because possible adaptive meaning some plastic responses, suggested role plasticity in maintaining genetic variation. In this paper, we present a study developmental norms reaction two populations Lobelia siphilitica (Lobeliaceae) three levels light availability. We investigated: (1) plas- ticity characters determining phenological timing end-of-season traits, (2) shape ontogenetic plant height number leaves (Time, Environment, Phenotype) space. found variation for bolting time, fruit production, final leaf number, rate stem elongation, production. detected height, leaves, rates growth rate. The reveal differences among genotypes both their average (i.e., across environments) ontogenies responses trajectories. other hand, show only significant Time by Treatment Genotype effect. ge- notypes can be due either or its duration. addition, same phenotype may produced different trajectories, e.g., rapid early short duration vs. slower longer response selection will depend degree separation control amount these aspects development. These results suggest that including data studies broadens considerably our understanding how phenotypes respond se- lection evolve.