Electrical signals in avocado trees: responses to light and water availability conditions.

Plant responses to environmental changes are associated with electrical excitability and signaling; automatic and continuous measurements of electrical potential differences (DeltaEP) between plant tissues can be effectively used to study information transport mechanisms and physiological responses that result from external stimuli on plants. The generation and conduction of electrochemical impulses within plant different tissues and organs, resulting from abiotic and biotic changes in environmental conditions is reported. In this work, electrical potential differences are monitored continuously using Ag/AgCl microelectrodes, inserted 5 mm deep into sapwood at two positions in the trunks of several Avocado trees. Electrodes are referenced to a non polarisable Ag/AgCl microelectrode installed 20 cm deep in the soil. Systematic patterns of DeltaEP during absolute darkness, day-night cycles and different conditions of soil water availability are discussed as alternative tools to assess early plant stress conditions.