Immediate oxidative burst onto the leaves after cutting the stem or flooding the roots of Nicotiana benthamiana

Plants may use a common defense system to respond to various abiotic and biotic stresses. Some hypotheses have suggested that there is a systemic signal that originates from the site of stress and that translocates to distant parts of the plant. We have detected an immediate oxidative burst onto the leaves after cutting the stem that lasted for 3 minutes and an immediate oxidative burst onto the leaves after flooding the roots of Nicotiana benthamiana that lasted for 20 minutes. Both of the two oxidative bursts were generated within 30 seconds. This strongly indicated that the systemic signal was not a transportable molecule from the site of stress and that it could be some form of electrical signalling.