Data from: Silicon mediates geographic variation of herbivory-related traits in a widespread plant invader

Silicon, the Earth’s second most abundant element, affects plant defenses
across large geographic scales, which is an interesting yet mostly
unexplored issue for non-native species. We investigated silicon-mediated
variation in defensive/nutritional traits and palatability to generalist
herbivores in 16 geographic populations of the invasive grass Spartina
alterniflora collected from native and introduced ranges. We found that
silicon supplementation generally increased leaf silicon content, which
then enhanced plant physical/chemical defenses and reduced nutrition,
ultimately impeding the growth of generalists. Yet, the pathways of
silicon accumulation affecting generalists differed between plant
provenances: enhancing quantitative and qualitative chemical defenses in
native populations, but improving quantitative chemical and structural
defenses in introduced ones. This suggests a silicon-mediated shift in
Spartina’s defense strategy following introduction. Our findings provide
insights into how non-native plants utilize silicon to enhance defenses,
emphasizing the importance of metalloid defenses in invasion success.