Data from: Shifts in woody plant defense syndromes during leaf development

1. Herbivores target young leaves in forests worldwide. How this strong
and predictable selection pressure has shaped plant defense syndromes
remains unclear. Specifically, whether young leaf herbivory has led to
general global patterns of shifting leaf defences during lead development
(i.e. ontogenetic trajectories) remains unknown but likely. 2. Using
meta-analysis, we have synthesized developmental shifts in chemical,
physical, and indirect defence traits, as well as leaf nutrient content,
during leaf expansion and maturation across 124 woody plant species. Leaf
traits were compared for immature young leaves versus mature leaves within
studies, and these developmental shifts were then compared across studies
to characterize general patterns. 3. Traits shifted strongly during leaf
maturation, giving rise to discrete defence syndromes, with young leaves
having significantly greater nutrient and secondary chemistry
concentrations but reduced toughness and indirect defence traits than
mature leaves. These patterns corroborate a growing consensus on the
importance of ontogeny in plant defences, illustrating ontogenetic
trajectories at the scale of leaves. 4. Trait developmental shifts were
stronger in species with synchronous than asynchronous leaf flushing, but
whether this reflects variation across biomes remains unclear. 5. Future
research on under-studied traits, such as alkaloids, cyanogenesis, leaf
phosphorus content, and indirect defence traits, and in a more
biogeographic context will provide additional insights into the generality
of shifts in defence syndromes during leaf development.