Aim: High foliar silicon (henceforth Si) concentration protects plant tissues against herbivory but protection against several abiotic stressors has been proposed too, though the adaptive significance of these functions is still being debated. We aimed to explore the potential relationships between foliar Si content and chronic wind exposure across a large scale and multiple species, and analyze an overlooked alternative or complementary function of silicon in leaves: mechanical protection against wind.

Location: Mainland China.

Time period: From July to September during 2012–2014.

Major taxa studied: 282 vascular plant species in predominantly herbaceous communities.

Methods: We compiled a dataset for leaf silicon concentration [Si] across 27 sites and 153 herbaceous plots comprising the major climate zones of China. We hypothesized that evolutionary lineages that generally have high [Si] should show positive relationships between leaf [Si] and mean annual wind speed.

Results: Within major families with generally high [Si] (especially grasses, sedges and composites), leaf [Si] is consistently positively correlated with mean wind speed among species across China. For the seven widespread monocot species with high leaf [Si], including the globally widely distributed common reed (Phragmites australis), intraspecific variation in leaf [Si] follows the same consistent positive correlation with mean wind speed.

Main conclusions: Our findings suggest high leaf [Si] is likely to have widespread adaptive value for wind exposure of leaves, at least in several very widespread families and species of herbaceous plants. Damage from wind is a danger for plants in many ecosystems, and hence these findings are of global significance and indicate further research into large scale variation of leaf Si and mechanical traits in relation to wind exposure will likely be illuminating.