EDTA-Facilitated Collection of Phloem Exudates for Chemical Analyses

Phloem exudates can be collected using several methods, including the ethylenediaminetetraacetic acid (EDTA)-facilitated method. Plant parts, such as leaves or inflorescences, are cut, and the cut edges are immediately placed into EDTA solution, which prevents plugging of sieve tubes. After this first inoculation, plant parts are transferred to water, into which phloem exudates are collected for a few hours. Inoculation and collection take place in the dark at high relative humidity. The samples can subsequently be used for different chemical analyses of RNA, proteins and various primary and specialized metabolites. This method can be applied to a wide range of plant species and plant parts as well as in various physiological and ecological research contexts.