Vacuolar pH in radish cotyledonal mesophyll cells

摘要

The vacuolar pH in cotyledonal mesophyll cells from radish (Raphanus sativusL. var.sativus) seedlings was determined from vacuoles, isolated from protoplasts through osmotic shock, by means of measurement of vacuole extracts with a pH meter and the “methylamine method”, and gave mean pH values of 6.28 and 6.26, respectively. Direct in situ measurements of the vacuolar pH from intact leaf tissue were recorded with pH-sensitive microelectrodes and gave a mean value of 6.0. The results are discussed with respect to possible erroneous pH measurements and the vacuolar location of specific anabolic reacti