Leaf wetness traits have often been used to describe ecophysiological and ecohydrological processes. However, the effect of droplet size when measuring these traits and their use as proxies for processes such as leaf water uptake have rarely been evaluated.
Matos and Rosado explored these missing links and found the water droplet volume does matter when measuring leaf wetness traits. Leaf wetness traits were not related to leaf water uptake. They concluded that the standardization of droplet volumes and the validation of leaf wetness traits are necessary before using them to infer ecophysiological processes.
Ilaíne S. Matos, Bruno H. P. Rosado, 2016, 'Retain or repel? Droplet volume does matter when measuring leaf wetness traits', Annals of Botany, vol. 117, no. 6, pp. 1045-1052 http://dx.doi.org/10.1093/aob/mcw025