The conduction of sap : II. Detection of vibrations produced by sap cavitation in Ricinus xylem.

An apparatus has been constructed for the detection of vibrations generated within plant tissue. This can detect vibrations due to water cavitation within fern sporangia. Using this detector 'clicks' have been obtained from Ricinus petioles and leaves in a condition when, from previous work, water cavitation might be expected.Evidence is provided to show: 1. That 'click' production is correlated with the water status of the plant tissue. 2. There are reasons for opposing the possibility that 'clicks' result from tissue fracture alone. 3. The 'clicks' may be detected in a wide range of plants. The implications of the apparent vulnerability of water conducting systems in plants are discussed.