Probing apoplastic ion relations in Vicia Faba as influenced by nutrition and gas exchange

Abstract

A novel and non-invasive method to probe the apoplastic space is presented. Ionselective microprobes are inserted through open stomata until contact with the apoplastic fluid is achieved. It is demonstrated how absolute values of H+-, K+-, Ca2+-, NH4+-, Cl--activities, and CO2 partial pressures, as well as continuous changes thereof can be reliably measured while superimposing physiological challenge. The technique also permits the use of intact plants, thus guaranteeing the acquisition of data from an undisturbed biological system. Details of microprobe fabrication are given.