Electrochemical mapping of indole-3-acetic acid and salicylic acid in whole pea seedlings under normal conditions and salinity

•Electrochemical detection for visual analysis of IAA and SA in plants based on paper-based analytical devices.•A multichannel electrochemical station was used to improve the detection throughput.•Contents of IAA and SA in pea seedlings could be obtained and presented with the form of heat maps.•Levels of IAA and SA in Pea seedlings under normal conditions and salinity could be differentiated.