High pH-values and secretion of ions on leaf surfaces: A characteristic of the phylloplane of Malvaceae

Summary All of 19 different species of Malvaceae have high pH-values, pH 9.5 or higher, on one or both surfaces of mature leaves. This is due to the secretion of magnesium and potassium carbonate and bicarbonate. The unusual pH and ionic composition may be important for parasites and pathogens living in the phylloplane of Malvaceae.