Potassium Involvement in Stomatal Movements of Paphiopedilum

There are conflicting reports about whether guard cells of Paphiopedilumspp. accumulate K during stomatal opening. In this study X-raymicroprobe analysis and histochemical staining for K indicatedthat K accumulated in guard cells in leaves of Paphiopedilumspp. when stomata opened. Additionally, stomatal opening inepidermal strips of P. harrisseanum could only be induced inan MES buffered KC1 medium. Element analysis ofP. harrisseanumepidermis also indicated substantial levels of K, Na and Cawithin the tissue. We conclude that K is involved in the stomatal movements ofPaphiopedilum. Key words: K⁺ transport, Paphiopedilum, Stomatal movements