Filter strip as a method of choice for apoplastic fluid extraction from maize roots

•Apoplastic washing fluid and fluid extracted by filter paper strips were compared.•Cytoplasmic markers and antioxidative components of the extracts were analyzed.•Filter strips method enables small amounts of concentrated and uncontaminated fluid.•This is an advanced method that avoids cytoplasmic contamination and dilution.•Filter strips facilitate precise analysis of metabolites in root apoplastic fluid.