The mechanisms for the foliar absorption of nutrients are poorly understood, and it has been suggested that leaf properties could potentially have impact upon the foliar absorption of nutrients.
Using methyl jasmonate (MeJA) to alter leaf properties, Cui et al. utilize traditional analytical approaches in addition to synchrotron-based X-ray fluorescence microscopy to investigate the absorption of foliar-applied Zn, Mn, and Fe in sunflower (Helianthus annuus), tomato (Solanum lycopersicum), and soybean (Glycine max). They find that the combined thickness of cuticle and epidermal cell wall plays an important role in influencing the absorption of foliar-applied nutrients.
Li, C., Wang, P., Menzies, N. W., Lombi, E., & Kopittke, P. M. (2017). Effects of changes in leaf properties mediated by methyl jasmonate (MeJA) on foliar absorption of Zn, Mn and Fe. Annals of Botany, 120(3), 405–415. https://doi.org/10.1093/aob/mcx063